ThePresident's Commission On

THE
ACCIDENT
AT TMI
John G. Kemeny, Chairman
President, Dartmouth College

Bruce Babbitt
Governor of Arizona
Patrick E. Haggerty
Honorary Chairman andGeneral Director
Texas Instruments Incorporated
Carolyn Lewis
Associate Professor
Graduate School of Journalism
Columbia University
Paul A. Marks
Vice President for Health Sciencesand Frode Jensen Professor
Columbia University
Cora B. Marrett
Professor of Sociology andAfro-American Studies
University of Wisconsin-Madison
Lloyd McBride
President
United Steelworkers of America

Harry C. McPherson
PartnerVerner, Liipfert,
Bernhard, and McPherson
Russell W. Peterson
President
National Audubon Society
Thomas H. Pigford
Professor and Chairman
Department of Nuclear
Engineering
University of California at
Berkeley
Theodore B. Taylor
Visiting Lecturer
Department of Mechanicaland Aerospace Engineering
Princeton University
Anne D. TrunkResident
Middletown, Pennsylvania

Stanley M. Gorinson, Chief Counsel
Kevin P. Kane, Deputy Chief Counsel
Associate Chief Counsel
Charles A. Harvey, Jr.
Stan M. Helfman
Winthrop A. Rockwell
Vincent L. Johnson, Director of Technical Staff
Task Force Heads
Russell R. Dynes
Jacob I. Fabrikant
Leonard Jaffe
David M. Rubin
Francis T. Hoban, Director of Administration
Barbara Jorgenson, Public Information Director
Patrick Young, Senior Writer
Consultants to the Chairman
Harold Bruff
Bruce T. Lundin
Jonathan Moore

PREFACETHE CHARGE TO THE COMMISSIONOn March 28, 1979, the United States experienced the worst accident
in the history of commercial nuclear power generation. Two weeks later,
the President of the United States established a Presidential Commission.
The President charged the 12-member Commission as follows:"The purpose of the Commission is to conduct a comprehensive study
and investigation of the recent accident involving the nuclear power
facility on Three Mile Island in Pennsylvania. The Commission's study
and investigation shall include:(a) a technical assessment of the events and their causes;
this assessment shall include, but shall not be limited to, anevaluation of the actual and potential impact of the events on
the public health and safety and on the health and safety ofworkers;(b)

an analysis of the role of the managing utility;(c) an assessment of the emergency preparedness and responseof the Nuclear Regulatory Commission and other federal, state,
and local authorities;(d) an evaluation of the Nuclear Regulatory Commission's
licensing, inspection, operation, and enforcement procedures
as applied to this facility;(e) an assessment of how the public's right to information
concerning the events at TMI was served and of the steps whichshould be taken during similar emergencies to provide thepublic with accurate, comprehensible, and timely information;and(f)appropriate recommendations based upon the Commission's
findings."

1

PREFACE
THE ACCIDENT
At 4:00 a.m. on March 28, 1979, a serious accident occurred at theThree Mile Island 2 nuclear power plant near Middletown, Pennsylvania.
The accident was initiated by mechanical malfunctions in the plant andmade much worse by a combination of human errors in responding to it.
(For details see "Account of the Accident" within this volume.) During
the next 4 days, the extent and gravity of the accident was unclear to
the managers of the plant, to federal and state officials, and to theWhat is quite clear is that its impact, nationally andgeneral public.
internationally, has raised serious concerns about the safety of nuclear
This Commission was established in response to those concerns.
power.
WHAT WE DID
The investigation of the Commission was carried out by our able andWe also had the help of a number of consultants andhard-working staff.
It is primarily due to the work of thecommissioned several studies.
staff that we accomplished the following.
We examined with great care the sequence of events that occurred
during the accident, to determine what happened and why. We haveattempted to evaluate the significance of various equipment failures aswell as the importance of actions (or failures of actions) on the partsof individuals and organizations.
We analyzed the various radiation releases and came up with thebest possible estimates of the health effects of the accident. In
addition, we looked more broadly into how well the health and safety of
the workers was protected during normal operating conditions, and how
well their health and safety and that of the general public would havebeen protected in the case of a more serious accident.
We conducted an in-depth examination of the role played by theWe examined possible problems ofutility and its principal suppliers.
organization, procedures, and practices that might have contributed toSince the major cause of the accident was due tothe accident.
inappropriate actions by those who were operating the plant andsupervising that operation, we looked very carefully at the training
programs that prepare operators and the procedures under which they
operate.
As requested by the President, we examined the emergency plans thatwere in place at the time of the accident. We also probed the responses
to the accident by the utility, by state and local governmental agencies
in Pennsylvania, and by a variety of federal agencies. We looked for
deficiencies in the plans and in their execution in order to be able to
make recommendations for improvements for any future accident. In thisprocess we had in mind how well the response would have worked if thedanger to public health had been significantly greater.
We examined the coverage of the accident by the news media. This
was a complex process in which we had to separate out whether errors inmedia accounts were due to ignorance or confusion on the part of theofficial sources, to the way they communicated this information to the2

PREFACE
media, or to mistakes committed by the reporters themselves. We examined
what sources were most influential on the people who needed immediate
information, and how well the public was served by the abundant coverage
We also attempted to evaluate whether the coveragethat was provided.
tended to exaggerate the seriousness of the accident either byselectively using alarming quotes more than reassuring ones, or throughpurposeful sensationalism.
Finally, we spent a great deal of time on the agency that had amajor role in all of the above: the Nuclear Regulatory Commission. The
President gave us a very broad charge concerning this agency. We
therefore tried to understand its complex structure and how well it
functions, its role in licensing and rulemaking, how well it carries out
its mission through its inspection and enforcement program, the role itplays in monitoring the training of operators, and its participation in
the response to the emergency, including the part it played in providing
information to the public.
We took more than 150 formal depositions and interviewed a
At our public hearings we
significantly larger number of individuals.
heard testimony under oath from a wide variety of witnesses. We collectedvoluminous material that will fill about 300 feet of shelf-space in a
All of this material will be placed into the National Archives.
library.
The most important information extracted from this in each of the areas
will appear in a series of "Staff Reports to the Commission."
Based on all of this information, the Commission arrived at anumber of major findings and conclusions. In turn, these findings led
the Commission to a series of recommendations responsive to the
President's charge.
At the beginning of this volume will be found an overview of ourinvestigation, followed by those findings and recommendations which
commanded a significant consensus among the members of the Commission.
Each recommendation was approved by a majority of Commissioners.
WHAT WE DID NOT DO
It is just as important for the reader to understand what theCommission did not do.
Our investigation centered on one accident at one nuclear power
plant in the United States. While acting under the President's charge,
we had to look at a large number of issues affecting many different
organizations; there are vast related issues which were outside ourcharge, and which we could not possibly have examined in a 6-monthinvestigation.
We did not examine the entire nuclear industry. (Although, throughour investigation of the Nuclear Regulatory Commission, we have at least
some idea of the standards being applied to it across the board.) We
have not looked at the military applications of nuclear energy. We did
not consider nuclear weapons proliferation. We have not dealt with thequestion of the disposal of radioactive waste or the dangers of theaccumulation of waste fuel within nuclear power plants adjacent to the3

PREFACE
We made no attempt to examine the entire fuelcontainment buildings.
cycle, starting with the mining of uranium. And, of course, we made no
examination of the many other sources of radiation, both natural andman-made, that affect all of us.
We have not attempted to evaluate the relative risks involved in
We are aware of a number of studies thatalternate sources of energy.
try to do this. We are also aware that some of these studies are
subjects of continuing controversy.
We did not attempt to reach a conclusion as to whether, as a matterof public policy, the development of commercial nuclear power should becontinued or should not be continued. That would require a much broader
investigation, involving economic, environmental, and political
We are aware that there are 72 operating reactors inconsiderations.
the United States with a capacity of 52,000 megawatts of electric
An additional 92 plants have received construction permits andenergy.
are in various stages of construction. If these are completed, they
will roughly triple the present nuclear capacity to generateThis would be a significant fraction of the total U.S.
electricity.
electrical generating capacity of some 600,000 megawatts. In addition,
there are about 200 nuclear power plants in other countries throughout
the world.
Therefore, the improvement of the safety of existing and planned
nuclear power plants is a crucial issue. It is this issue that ourreport addresses, those changes that can and must be made as a result of
the accident -- the legacy of Three Mile Island.

4

OVERVIEWOVERALL CONCLUSION

In announcing the formation of the Commission, the President of theUnited States said that the Commission "will make recommendations toenable us to prevent any future nuclear accidents." After a 6-monthinvestigation of all factors surrounding the accident and contributing
to it, the Commission has concluded that:
To prevent nuclear accidents as serious as Three Mile
Island, fundamental changes will be necessary in the organization,
procedures, and practices -- and above all -- in the attitudes of
the Nuclear Regulatory Commission and, to the extent that theinstitutions we investigated are typical, of the nuclear industry.
We do notThis conclusion speaks of necessary fundamental changes.
claim that our proposed recommendations are sufficient to assure thesafety of nuclear power.
Given the nature of its Presidential mandate, its time limitations,and the complexity of both energy and comparative "risk-assessment"
issues, this Commission has not undertaken to examine how safe is "safeenough" or the broader question of nuclear versus other forms of energy.
The Commission's findings with respect to the accident and theregulation of the nuclear industry -- particularly the current andpotential state of public safety in the presence of nuclear power -have, we believe, implications that bear on the broad question ofenergy.
But the ultimate resolution of the question involves the kindof economic, environmental, and foreign policy considerations that can
only be evaluated through the political process.
Our findings do not, standing alone, require the conclusion that
nuclear power is inherently too dangerous to permit it to continue andexpand as a form of power generation. Neither do they suggest that thenation should move forward aggressively to develop additional commercial
They simply state that if the country wishes, for larger
nuclear power.
reasons, to confront the risks that are inherently associated with7

OVERVIEW
nuclear power, fundamental changes are necessary if those risks are to
be kept within tolerable limits.
We are very much aware that many other investigations into theaccident are under way. There are several investigations by Congress,
the NRC self-investigation, and a number of studies by the industry.
Some will examine individual issues in much greater depth than we wereable to do. And, no doubt, additional insights will emerge out of these
It is our hope that the results of our efforts
various investigations.
may aid and accelerate the progress of the ongoing investigations, andhelp to bring about the required changes promptly.
ATTITUDES AND PRACTICES
Our investigation started out with an examination of the accident
at Three Mile Island (TMI). This necessarily led us to look into therole played by the utility and its principal suppliers. With ourin-depth investigation of the Nuclear Regulatory Commission (NRC), we
gained a broader insight into the attitudes and practices that prevailin portions of the industry. However, we did not examine the industry
in its totality.
Popular discussions of nuclear power plants tend to concentrate onquestions of equipment safety. Equipment can and should be improved to
add further safety to nuclear power plants, and some of our recommendations deal with this subject. But as the evidence accumulated, it
became clear that the fundamental problems are people-related problems
and not equipment problems.
When we say that the basic problems are people-related, we do notmean to limit this term to shortcomings of individual humanbeings -- although those do exist. We mean more generally that ourinvestigation has revealed problems with the "system" that manufactures,operates, and regulates nuclear power plants. There are structuralproblems in the various organizations, there are deficiencies in various
processes, and there is a lack of communication among key individuals
and groups.
We are convinced that if the only problems were equipment problems,
this Presidential Commission would never have been created. The
equipment was sufficiently good that, except for human failures, themajor accident at Three Mile Island would have been a minor incident.
But, wherever we looked, we found problems with the human beings who
operate the plant, with the management that runs the key organization,
and with the agency that is charged with assuring the safety of nuclear
power plants.
In the testimony we received, one word occurred over and overagain.
That word is "mindset." At one of our public hearings,
Roger Mattson, director of NRC's Division of Systems Safety, used thatword five times within a span of 10 minutes. For example: "I think[ the] mindset [was] that the operator was a force for good, that if you
discounted him, it was a measure of conservatism." In other words, they8

OVERVIEW
concentrated on equipment, assuming that the presence of operators could
only improve the situation -- they would not be part of the problem.
After many years of operation of nuclear power plants, with noevidence that any member of the general public has been hurt, the belief
that nuclear power plants are sufficiently safe grew into a conviction.
One must recognize this to understand why many key steps that could have
prevented the accident at Three Mile Island were not taken. The
Commission is convinced that this attitude must be changed to one thatsays nuclear power is by its very nature potentially dangerous, and,
therefore, one must continually question whether the safeguards alreadyin place are sufficient to prevent major accidents. A comprehensive
system is required in which equipment and human beings are treated withequal importance.
We note a preoccupation with regulations. It is, of course, theresponsibility of the Nuclear Regulatory Commission to issue regulations
to assure the safety of nuclear power plants. However, we are convincedthat regulations alone cannot assure safety. Indeed, once regulations
become as voluminous and complex as those regulations now in place, they
can serve as a negative factor in nuclear safety. The regulations are
so complex that immense efforts are required by the utility, by its
suppliers, and by the NRC to assure that regulations are complied with.
The satisfication of regulatory requirements is equated with safety.
This Commission believes that it is an absorbing concern with safetythat will bring about safety -- not just the meeting of narrowlyprescribed and complex regulations.
We find a fundamental fault even with the existing body of reguWhile scientists and engineers have worried for decades about
lations.
the safety of nuclear equipment, we find that the approach to nuclear
safety had a major flaw. It was natural for the regulators and theindustry to ask: "What is the worst kind of equipment failure that canoccur?" Some potentially serious scenarios, such as the break of a hugepipe that carries the water cooling the nuclear reactor, were studied
extensively and diligently, and were used as a basis for the design ofA preoccupation developed with such large-break accidents asplants.
did the attitude that if they could be controlled, we need not worry
about the analysis of "less important" accidents.
Large-break accidents require extremely fast reaction, which
therefore must be automatically performed by the equipment. Lesser
accidents may develop much more slowly and their control may be
dependent on the appropriate actions of human beings. This was thetragedy of Three Mile Island, where the equipment failures in theaccident were significantly less dramatic than those that had beenthoroughly analyzed, but where the results confused those who managed
the accident. A potentially insignificant incident grew into the TMI
accident, with severe damage to the reactor. Since such combinations ofminor equipment failures are likely to occur much more often than thehuge accidents, they deserve extensive and thorough study. In addition,
they require operators and supervisors who have a thorough understandingof the functioning of the plant and who can respond to combinations ofsmall equipment failures.

9OVERVIEW
The most serious "mindset" is the preoccupation of everyone withthe safety of equipment, resulting in the down-playing of the importanceof the human element in nuclear power generation. We are tempted to saythat while an enormous effort was expended to assure that safety-related
equipment functioned as well as possible, and that there was backup
equipment in depth, what the NRC and the industry have failed torecognize sufficiently is that the human beings who manage and operate
the plants constitute an important safety system.
CAUSES OF THE ACCIDENTOther investigations have concluded that, while equipment failures
initiated the event, the fundamental cause of the accident was "operator
error." It is pointed out that if the operators (or those who
supervised them) had kept the emergency cooling systems on through theearly stages of the accident, Three Mile Island would have been limited
While we agree that thisto a relatively insignificant incident.
statement is true, we also feel that it does not speak to thefundamental causes of the accident.
Let us consider some of the factors that significantly contributed
to operator confusion.
First of all, it is our conclusion that the training of TMI
operators was greatly deficient.
While training may have been adequate
for the operation of a plant under normal circumstances, insufficientattention was paid to possible serious accidents. And the depth ofunderstanding, even of senior reactor operators, left them unprepared todeal with something as confusing as the circumstances in which theyfound themselves.
Second, we found that the specific operating procedures, which wereapplicable to this accident, are at least very confusing and could beread in such a way as to lead the operators to take the incorrect
actions they did.
Third, the lessons from previous accidents did not result in new,clear instructions being passed on to the operators. Both points areillustrated in the following case history.
A senior engineer of the Babcock & Wilcox Company (suppliers of thenuclear steam system) noted in an earlier accident, bearing strong
similarities to the one at Three Mile Island, that operators had
mistakenly turned off the emergency cooling system. He pointed out that
we were lucky that the circumstances under which this error wascommitted did not lead to a serious accident and warned that under othercircumstances (like those that would later exist at Three Mile Island), avery serious accident could result. He urged, in the strongest terms,
that clear instructions be passed on to the operators. This memorandum
was written 13 months before the accident at Three Mile Island, but no
new instructions resulted from it. The Commission's investigation ofthis incident, and other similar incidents within B&W and the NRC,
indicates that the lack of understanding that led the operators to
10

OVERVIEW
incorrect action existed both within the Nuclear Regulatory Commission
and within the utility and its suppliers.
We find that there is a lack of "closure" in the system -- that is,important safety issues are frequently raised and may be studied to somedegree of depth, but are not carried through to resolution; and thelessons learned from these studies do not reach those individuals andagencies that most need to know about them. This was true in the B&W
incident described above, it was true about various warnings within NRC
that inappropriate operator actions could result in the case of certain
small-break accidents, and it was true in several examples of questions
raised in connection with licensing procedures that were not followed totheir conclusion by the NRC staff.
There are many other examples mentioned in our report that indicate
the lack of attention to the human factor in nuclear safety. We note
only one more (a fourth) example. The control room, through which theoperation of the TMI-2 plant is carried out, is lacking in many ways.
The control panel is huge, with hundreds of alarms, and there are somekey indicators placed in locations where the operators cannot see them.
There is little evidence of the impact of modern information technology
within the control room. In spite of this, this control room might beadequate for the normal operation of nuclear power plants.
However, it is seriously deficient under accident conditions.
During the first few minutes of the accident, more than 100 alarms wentoff, and there was no system for suppressing the unimportant signals sothat operators could concentrate on the significant alarms. Information
was not presented in a clear and sufficiently understandable form; forexample, although the pressure and temperature within the reactor
coolant system were shown, there was no direct indication that the
combination of pressure and temperature meant that the cooling water was
turning into steam.
Overall, little attention had been paid to theinteraction between human beings and machines under the rapidly changing
and confusing circumstances of an accident. Perhaps these design
failures were due to a concentration on the large-break accidents -which do not allow time for significant operator action -- and thedesign ignored the needs of operators during a slowly developing
small-break (TMI-type) accident. While some of us may favor a complete
modernization of control rooms, we are all agreed that a relatively few
and not very expensive improvements in the control room could havesignificantly facilitated the management of the accident.
In conclusion, while the major factor that turned this incident
into a serious accident was inappropriate operator action, many factors
contributed to the action of the operators, such as deficiencies intheir training, lack of clarity in their operating procedures, failureof organizations to learn the proper lessons from previous incidents,
and deficiencies in the design of the control room. These shortcomings
are attributable to the utility, to suppliers of equipment, and to thefederal commission that regulates nuclear power. Therefore -- whether
or not operator error "explains" this particular case -- given all theabove deficiencies, we are convinced that an accident like Three Mile
Island was eventually inevitable.
11

OVERVIEW
SEVERITY OF THE ACCIDENT
Just how serious was the accident? Based on our investigation of
the health effects of the accident, we conclude that in spite of serious
damage to the plant, most of the radiation was contained and the actual
release will have a negligible effect on the physical health ofindividuals. The major health effect of the accident was found to bemental stress.
The amount of radiation received by any one individual outside theplant was very low. However, even low levels of radiation may result inthe later development of cancer, genetic defects, or birth defects amongchildren who are exposed in the womb. Since there is no direct way ofmeasuring the danger of low-level radiation to health, the degree ofDifferent scientists makedanger must be estimated indirectly.
different assumptions about how this estimate should be made and,Fortunately, in this case the radiation
therefore, estimates vary.
doses were so low that we conclude that the overall health effects will
There will either be no case of cancer or the number ofbe minimal.
cases will be so small that it will never be possible to detect them.
The same conclusion applies to the other possible health effects. The
reasons for these conclusions are as follows.
An example of a projection derived for the total number ofradiation-induced cancers among the population affected by the accident
at TMI was 0.7. This number is an estimate of an average, such as theone that appears in the statement: "The average American family has 2.3
children."In the case of TMI, what it really means is that each of some 2
million individuals living within 50 miles has a miniscule additionalchance of dying of cancer, and when all of these minute probabilities
are added up, they total 0.7. In such a situation, a mathematical law
known as a Poisson distribution (named after a famous French
If the estimated average is 0.7, then themathematician) applies.
actual probabilities for cancer deaths due to the accident work out as
There is a roughly 50 percent chance that there will be no
follows:
additional cancer deaths, a 35 percent chance that one individual will
die of cancer, a 12 percent chance that two people will die of cancer,
and it is practically certain that there will not be as many as fivecancer deaths.
Similar probabilities can be calculated for our various estimates.
All of them have in common the following: It is entirely possible that
not a single extra cancer death will result. And for all our estimates,
it is practically certain that the additional number of cancer deaths
will be less than 10.

Since a cancer caused by nuclear radiation is no different from anyother cancer, additional cancers can only be determined statistically.
We know from statistics on cancer deaths that among the more than 2
million people living within 50 miles of TMI, eventually some 325,000
people will die of cancer, for reasons having nothing to do with the12

OVERVIEW
nuclear power plant.
Again, this number is only an estimate, and theactual figure could be as much as 1,000 higher or 1,000 lower.
Therefore, there is no conceivable statistical method by which fewer
than 10 additional deaths would ever be detected. Therefore, theaccident may result in no additional cancer deaths or, if there wereany, they would be so few that they could not be detected.
We found that the mental stress to which those living within thevicinity of Three Mile Island were subjected was quite severe. There
were several factors that contributed to this stress. Throughout thefirst week of the accident, there was extensive speculation on just how
serious the accident might turn out to be. At various times, senior
officials of the NRC and the state government were considering thepossibility of a major evacuation. There were a number of advisories
recommending steps short of a full evacuation. Some significant
fraction of the population in the immediate vicinity voluntarily left
the region.
NRC officials contributed to the raising of anxiety in the
period from Friday to Sunday (March 30-April 1). On Friday, a mistakeninterpretation of the release of a burst of radiation led some NRC
officials to recommend immediate evacuation.
And on Friday Governor
Thornburgh advised pregnant women and preschool aged children within 5
miles of TMI to leave the area. On Saturday and Sunday, other NRC
officials mistakenly believed that there was an imminent danger of an
explosion of a hydrogen bubble within the reactor vessel, and evacuation
was again a major subject of discussion.
We conclude that the most serious health effect of the accident was
severe mental stress, which was short-lived. The highest levels of
distress were found among those living within 5 miles of TMI and infamilies with preschool children.
There was very extensive damage to the plant. While the reactor
itself has been brought to a "cold shutdown," there are vast amounts ofradioactive material trapped within the containment and auxiliarybuildings.
The utility is therefore faced with a massive cleanup
process that carries its own potential dangers to public health. The
ongoing cleanup operation at TMI demonstrates that the plant wasinadequately designed to cope with the cleanup of a damaged plant. The
direct financial cost of the accident is enormous. Our best estimate
puts it in a range of $1 to $2 billion, even if TMI-2 can be put backinto operation.
(The largest portion of this is for replacement power
estimated for the next few years.) And since it may not be possible toput it back into operation, the cost could even be much larger.
The accident raised concerns all over the world and led to alowering of public confidence in the nuclear industry and in the NRC.
From the beginning, we felt it important to determine not only how
serious the actual impact of the accident was on public health, butwhether we came close to a catastrophic accident in which a large numberof people would have died. Issues that had to be examined were whether
a chemical (hydrogen) or steam explosion could have ruptured the reactor
vessel and containment building, and whether extremely hot molten fuel13

OVERVIEW
could have caused severe damage to the containment. The danger wasnever -- and could not have been -- that of a nuclear explosion (bomb).
We have made a conscientious effort to get an answer to thisSince the accident was due to a complex combinationdifficult question.
of minor equipment failures and major inappropriate human actions, wehave asked the question: "What if one more thing had gone wrong?"
We explored each of several different scenarios representing achange in the sequence of events that actually took place. The greatest
concern during the accident was that significant amounts of radioactive
material (especially radioactive iodine) trapped within the plant might
Therefore, in each case, we asked whether the amountbe released.
released would have been smaller or greater, and whether large amounts
could have been released.
Some of these scenarios lead to a more favorable outcome than what
Several other scenarios lead to increases in theactually happened.
amount of radioactive iodine released, but still at levels that would
not have presented a danger to public health. But we have also explored
two or three scenarios whose precise consequences are much more
They lead to more severe damage to the core,difficult to calculate.
with additional melting of fuel in the hottest regions. These
consequences are, surprisingly, independent of the age of the fuel.
Because of the uncertain physical condition of the fuel, cladding,and core, we have explored certain special and severe conditions thatwould, unequivocally, lead to a fuel-melting accident. In this sequenceof events fuel melts, falls to the bottom of the vessel, melts throughthe steel reactor vessel, and finally, some fuel reaches the floor of
the containment building below the reactor vessel where there is enoughwater to cover the molten fuel and remove some of the decay heat. To
contain such an accident, it is necessary to continue removing decay
heat for a period of many months.
At this stage we approach the limits of our engineering knowledgeof the interactions of molten fuel, concrete, steel, and water, and eventhe best available calculations have a degree of uncertainty associatedOur calculations show that even if a meltdown occurred,with them.
there is a high probability that the containment building and the hardrock on which the TMI-2 containment building is built would have beenable to prevent the escape of a large amount of radioactivity. These
results derive from very careful calculations, which hold only insofar
We cannot be absolutely certain of theseas our assumptions are valid.
results.
Some of the limits of this investigation were: (1) We have notexamined possible consequences of operator error during or after thefuel melting process which might compromise the effectiveness ofcontainment; (2) We have not examined the vulnerability of the various
electrical and plumbing penetrations through the walls or the doorways
for people and equipment; (3) The analysis was specific to the TMI-2
design and location (for example, the bedrock under the plant); (4) We
14

OVERVIEW
recognize that we have only explored a limited number of alternatives tothe question "What if . . .?" and, others may come up with a plausible
scenario whose results would have been even more serious.
We strongly urge that research be carried out promptly to identify
and analyze the possible consequences of accidents leading to severe
core damage.
Such knowledge is essential for coping with results offuture accidents.
It may also indicate weaknesses in present designs,
whose correction would be important for the prevention of serious
accidents.
These uncertainties have not prevented us from reaching an overwhelming consensus on corrective measures.
Our reasoning is as follows:
Whether in this particular case we came close to a catastrophic accident
or not, this accident was too serious.
Accidents as serious as TMI
should not be allowed to occur in the future.
The accident got sufficiently out of hand so that those attempting
to control it were operating somewhat in the dark. While today thecauses are well understood, 6 months after the accident it is still
difficult to know the precise state of the core and what the conditions
are inside the reactor building. Once an accident reaches this stage,
one that goes beyond well-understood principles, and puts thosecontrolling the accident into an experimental mode (this happened during
the first day), the uncertainty of whether an accident could result inmajor releases of radioactivity is too high. Adding to this theenormous damage to the plant, the expensive and potentially dangerous
cleanup process that remains, and the great cost of the accident, wemust conclude that -- whatever worse could have happened -- the accident
had already gone too far to make it tolerable.
While throughout this entire document we emphasize that fundamental
changes are necessary to prevent accidents as serious as TMI, we must
not assume that an accident of this or greater seriousness cannot happen
again, even if the changes we recommend are made. Therefore, in
addition to doing everything to prevent such accidents, we must be fully
prepared to minimize the potential impact of such an accident on publichealth and safety, should one occur in the future.
HANDLING OF THE EMERGENCY
Another area of our investigation dealt with the questions ofwhether various agencies made adequate preparations for an emergency andwhether their responses to the emergency were satisfactory. Our findingis negative on both questions.
We are disturbed both by the highly uneven quality of emergency
plans and by the problems created by multiple jurisdictions in the caseof a radiation emergency.
Most emergency plans rely on prompt action at
the local level to initiate a needed evacuation or to take other protective action.
We found an almost total lack of detailed plans in thelocal communities around Three Mile Island. It is one of the manyironies of this event that the most relevant planning by local
15

OVERVIEW
authorities took place during the accident. In an accident in which
prompt defensive steps are necessary within a matter of hours,
insufficient advance planning could prove extremely dangerous.
We favor the centralization of emergency planning and response in asingle agency at the federal level with close coordination between it
and state and local agencies. Such agencies would need expert input
from many other organizations, but there should be a single agency thathas the responsibility both for assuring that adequate planning takes
place and for taking charge of the response to the emergency. This will
require organizational changes, since the agencies now best organized todeal with emergencies tend to have most of their experience with such
events as floods and storms, rather than with radiological events. And,insofar as radiological events require steps that go beyond those in anormal emergency, careful additional planning is needed.
A central concept in the current siting policy of the NRC is thatreactors should be located in a "low population zone" (LPZ), an areaaround the plant in which appropriate protective action could be taken
for the residents in the event of an accident. However, this concept is
implemented in a strange, unnatural, and round-about manner. To
determine the size of the LPZ, the utility calculates the amount ofUsingradiation released in a very serious hypothetical accident.
geographical and meteorological data, the utility then calculates thatarea within which an individual would receive 25,000 millirems or moreto the whole body, during the entire course of the accident. This areais the LPZ. The 25,000-millirem standard is an extremely large dose,
many times more serious than that received by any individual during theentire TMI accident.
The LPZ approach has serious shortcomings. First, because of theextremely large dose by which its size is determined, the LPZs for many
nuclear power plants are relatively small areas, 2 miles in the case of
TMI. Second, if an accident as serious as the one used to calculate the
LPZ were actually to occur, it is evident that many people living
outside the LPZ would receive smaller, but still massive doses ofradiation. Third, the TMI accident shows that the LPZ has little
relevance to the protection of the public -- the NRC itself wasconsidering evacuation distances as far as 20 miles, even though theaccident was far less serious than those postulated during siting. We
have therefore concluded that the entire concept is flawed.
We recommend that the LPZ concept be abandoned in siting and in
A variety of possible accidents should be
emergency planning.
considered during siting, particularly "smaller" accidents which have a
For each such accident, one should
higher probability of occurring.
calculate probable levels of radiation releases at a variety of
distances to decide the kinds of protective action that are necessary
Such protective actions may range from evacuation of anand feasible.
area near the plant, to the distribution of potassium iodide to protect
the thyroid gland from radioactive iodine, to a simple instruction topeople several miles from the plant to stay indoors for a specified
period of time. Only such an analysis can predict the true consequences
16

OVERVIEW
of a radiological incident and determine whether a particular site issuitable for a nuclear power plant. Similarly, emergency plans shouldhave built into them a variety of responses to a variety of possible
kinds of accidents. State and local agencies must be prepared with theappropriate response once information is available on the nature of an
accident and its likely levels of releases.
The response to the emergency was dominated by an atmosphere of
There was lack of communication at all levels.
almost total confusion.
Many key recommendations were made by individuals who were not in possession of accurate information, and those who managed the accident wereslow to realize the significance and implications of the events that had
taken place.
While we have attempted to address these shortcomings in
our recommendations, it is important to reiterate the fundamental
philosophy we stated above: One must do everything possible to prevent
accidents of this seriousness, but at the same time assume that such an
accident may occur and be prepared for response to the resulting
emergency.
The fact that too many individuals and organizations were
not aware of the dimensions of serious accidents at nuclear power plants
accounts for a great deal of the lack of preparedness and the poor
quality of the response.
PUBLIC AND WORKER HEALTH AND SAFETY
We have identified a number of inadequacies with respect to procedures and programs to prevent or minimize hazards to health fromradiation exposure from the operations of nuclear power plants. In
setting standards for permissible levels of worker exposure to radioactivity,in plant siting decisions, and in other areas related to health, the NRC
is not required to, and does not regularly seek, advice or review of its
health-related guidelines and regulations from other federal agencies
with radiation-related responsibilities in the area of health, forexample the Department of Health, Education, and Welfare (HEW) or theEnvironmental Protection Agency (EPA).
There is inadequate knowledge ofthe effects of low levels of ionizing radiation, of strategies to mitigate
the health hazards of exposure to radiation, and of other areas relating
to regulation setting to protect worker and public health. In
preparation for a possible emergency such as the accident at TMI-2,
various federal agencies (NRC, Department of Energy, HEW, and EPA) haveassigned responsibilities, but planning prior to the accident was sopoor that ad hoc arrangements among these federal agencies had to bemade to involve them and coordinate their activities.
The Commonwealth of Pennsylvania, its Bureau of Radiation
Protection and Department of Health -- agencies with responsibilities
for public health -- did not have adequate resources for dealing withradiation health programs related to the operation of TMI. The utility
was not required to, and did not, keep a record on workers of the total
work-related plans non-work-related (for example, medical or dental)
radiation exposure.
We make recommendations with respect to improving the coordinationand collaboration among federal and state agencies with radiation-related
17

OVERVIEW
We believe more emphasis is
responsibilities in the health area.
required on research on the health effects of radiation to provide asounder basis for guidelines and regulations related to worker andpublic health and safety. We believe that both the state and the utility
have an opportunity and an obligation to establish more rigorous
programs for informing workers and the public on radiation
health-related issues and procedures to prevent adverse health effectsof radiation.
RIGHT TO INFORMATIONThe President asked us to investigate whether the public's right toinformation during the emergency was well served. Our conclusion isagain in the negative. However, here there were many different causes,
and it is both harder to assign proper responsibility and more difficult
to come up with appropriate recommendations. There were serious
problems with the sources of information, with how this information wasconveyed to the press, and also with the way the press reported what it
heard.
We do not find that there was a systematic attempt at a "cover-up"by the sources of information. Some of the official news sources werethemselves confused about the facts and there were major disagreements
among officials. On the first day of the accident, there was an attemptby the utility to minimize its significance, in spite of substantial
evidence that it was serious. Later that week, NRC was the source of
Due to misinformation, and in one case (theexaggerated stories.
hydrogen bubble) through the commission of scientific errors, official
sources would make statements about radiation already released (or about
the imminent likelihood of releases of major amounts of radiation) thatwere not justified by the facts -- at least not if the facts had beencorrectly understood. And NRC was slow in confirming good news about theOn the other hand, the estimated extent of the damagehydrogen bubble.
to the core was not fully revealed to the public.
A second set of problems arose from the manner in which the facts
were presented to the press. Some of those who briefed the press lacked
the technical expertise to explain the events and seemed to be cut off
from those who could have provided this expertise. When those who did
have the knowledge spoke, their statements were often couched in"jargon" that was very difficult for the press to understand. The press
was further disturbed by the fact that, in order to cut down on theamount of confusion, a number of potential sources of information were
While this cut down on the
instructed not to give out information.
amount of confusion, it flew in the face of the long tradition of thepress of checking facts with multiple sources.
Many factors contributed to making this event one of the mostheavily covered media events ever. Given these circumstances, the media
generally attempted to give a balanced presentation which would notcontribute to an escalation of panic. There were, however, a few
notable examples of irresponsible reporting and some of the visual
images used in the reporting tended to be sensational.
18

OVERVIEW
Another severe problem was that even personnel representing the
major national news media often did not have sufficient scientific andengineering background to understand thoroughly what they heard, and did
not have available to them people to explain the information. This
problem was most serious in the reporting of the various releases ofradiation and the explanation of the severity (or lack of severity) of
these releases.
Many of the stories were so garbled as to make themuseless as a source of information.
We therefore conclude that, while the extent of the coverage wasjustified, a combination of confusion and weakness in the sources of
information and lack of understanding on the part of the media resulted
in the public being poorly served.
In considering the handling of information during the nuclear
accident, it is vitally important to remember the fear with respect tonuclear energy that exists in many human beings. The first applicationof nuclear energy was to atomic bombs which destroyed two major Japanesecities.
The fear of radiation has been with us ever since and is madeworse by the fact that, unlike floods or tornadoes, we can neither hear
nor see nor smell radiation. Therefore, utilities engaged in theoperation of nuclear power plants, and news media that may cover a
possible nuclear accident, must make extraordinary preparation for theaccurate and sensitive handling of information.
There is a natural conflict between the public's right to know andthe need of disaster managers to concentrate on their vital tasks
without distractions.
There is no simple resolution for this conflict.
But significant advance preparation can alleviate the problem. It is
our judgment that in this case, neither the utility nor the NRC nor the
media were sufficiently prepared to serve the public well.
THE NUCLEAR REGULATORY COMMISSION
We had a broad mandate from the President to investigate the
Nuclear Regulatory Commission.
When NRC was split off from the old
Atomic Energy Commission, the purpose of the split was to separate theregulators from those who were promoting the peaceful uses of atomic
energy.
We recognize that the NRC has an assignment that would be
difficult under any circumstances.
But, we have seen evidence that someof the old promotional philosophy still influences the regulatory
practices of the NRC. While some compromises between the needs ofsafety and the needs of an industry are inevitable, the evidence
suggests that the NRC has sometimes erred on the side of the industry's
convenience rather than carrying out its primary mission of assuringsafety.
Two of the most important activities of NRC are its licensing
function and its inspection and enforcement (I&E) activities.
We foundserious inadequacies in both.
In the licensing process, applications are only required to analyze"single-failure" accidents.
They are not required to analyze what
19

OVERVIEW
happens when two systems fail independently of each other, such as theevent that took place at TMI. There is a sharp delineation between
those components in systems that are "safety-related" and those that arenot.
Strict reviews and requirements apply to the former; the latterare exempt from most requirements -- even though they can have an effecton the safety of the plant. We feel that this sharp either/orInstead, there should be a system ofdefinition is inappropriate.
priorities as to how significant various components and systems are forthe overall safety of the plant. There seems to be a persistentassumption that plants can be made sufficiently safe to be"people-proof." Thus, not enough attention is paid to the training ofoperating personnel and operator procedures in the licensing process.
And, finally, plants can receive an operating license with several
safety issues still unresolved.
This places such a plant into aregulatory "limbo" with jurisdiction divided between two different
TMI-2 was in this status at the time of theoffices within NRC.
accident, 13 months after it received its operating license.
NRC's primary focus is on licensing and insufficient attention has
been paid to the ongoing process of assuring nuclear safety. An
important example of this is the case of "generic problems," that is,
problems that apply to a number of different nuclear power plants. Once
an issue is labeled "generic," the individual plant being licensed is
not responsible for resolving the issue prior to licensing. That, in
itself, would be acceptable, if there were a strict procedure within NRC
to assure the timely resolution of generic problems, either by its own
research staff, or by the utility and its suppliers. However, theevidence indicates that labeling of a problem as "generic" may provide aconvenient way of postponing decision on a difficult question.
The old AEC attitude is also evident in reluctance to apply new
While we would accept asafety standards to previously licensed plants.
need for reasonable timetables for "backfitting," we did not findevidence that the need for improvement of older plants was
systematically considered prior to Three Mile Island.
The existence of a vast body of regulations by NRC tends to focus
industry attention narrowly on the meeting of regulations rather than ona systematic concern for safety. Furthermore, the nature of some of theregulations, in combination with the way rate bases are established for
utilities, may in some instances have served as a deterrent for
utilities or their suppliers to take the initiative in proposing
measures for improved safety.
Previous studies of I&E have criticized this branch severely.
Inspectors frequently fail to make independent evaluations orinspections.
The manual according to which inspectors are supposed tooperate is so voluminous that many inspectors do not understandprecisely what they are supposed to do. There have been a number ofincidents in which inspectors have had difficulty in getting theirsuperiors to concentrate on serious safety issues. The analysis ofreported incidents by licensees has tended to concentrate on equipment
malfunction, and serious operator errors have not been focused on.
20

OVERVIEW
Finally, while the statutory authority to impose fines is fairly
limited, a previous study shows that I&E has made minimal use of eventhis authority.
Since in many cases NRC does not have the first-hand informationnecessary to enforce its regulations, it must rely heavily on theindustry's own records for its inspection and enforcement activities.
NRC accumulates vast amounts of information on the operating experienceof plants. However, prior to the accident there was no systematic
method of evaluating these experiences, and no systematic attempt tolook for patterns that could serve as a warning of a basic problem.
NRC is vulnerable to the charge that it is heavily equipment-oriented,
rather than people-oriented.
Evidence for this exists in the weak andunderstaffed branch of NRC that monitors operator training, in the factthat inspectors who investigate accidents concentrate on what went wrong
with the equipment and not on what operators may have done incorrectly,
in the lack of attention to the quality of procedures provided for
operators, and in an almost total lack of attention to the interaction
between human beings and machines.
In addition to all the other problems with the NRC, we are extremely
critical of the role the organization played in the response to theaccident.
There was a serious lack of communication among thecommissioners, those who were attempting to make the decisions about theaccident in Bethesda, the field offices, and those actually on site.
This lack of communication contributed to the confusion of the accident.
We are also skeptical whether the collegial mode of the five commissioners makes them a suitable body for the management of an emergency,
and of the agency itself.
We found serious managerial problems within the organization.
These problems start at the very top. It is not clear to us what the
precise role of the five NRC commissioners is, and we have evidence thatthey themselves are not clear on what their role should be. The hugebureaucracy under the commissioners is highly compartmentalized withinsufficient communication among the major offices.
We do not see
evidence of effective managerial guidance from the top, and we do see
evidence of some of the old AEC promotional philosophy in key officers
below the top. The management problems have been made much harder byadoption of strict rules that prohibit the commissioners from talking
with some of their key staff on issues involved in the licensing
process; we believe that these rules have been applied in an unnecessarily severe form within this particular agency. The geographic
spread, which places top management in Washington and most of the staff
in Bethesda and Silver Spring, Maryland (and in other parts of thecountry), also inhibits the easy exchange of ideas.
We therefore conclude that there is no well-thought-out, integrated
system for the assurance of nuclear safety within the current NRC.
We have found evidence of repeated in-depth studies and criticisms
both from within the agency and from without, but we found very little
21

OVERVIEW
evidence that these studies have resulted in significant improvement.
This fact gives us particular concern for the future of the present NRC.
For all these reasons we recommend a total restructuring of the
NRC. We recommend that it be an independent agency within the executive
branch, headed by a single administrator, who is in every sense chief
executive officer, to be chosen from outside NRC. The new administrator
must be provided with the freedom to reorganize and to bring new blood
into the restructured NRC's staff. This new blood could result in thechange of attitudes that is vital for the solution of the problems ofthe nuclear industry.
We have also recommended a number of other organizational andprocedural changes designed to make the new agency truly effective inassuring the safety of nuclear power plants. Included in these are an
oversight committee to monitor the performance of the restructured NRC
and mandatory review by HEW of radiation-related health issues.
THE UTILITY
When the decision was made to make nuclear power available for thecommercial generation of energy, it was placed into the hanr1c of theexisting electric utilities. Nuclear power requires management qualifications
and attitudes of a very special character as well as an extensive support
We feel that insufficient attention
system of scientists and engineers.
was paid to this by the General Public Utilities Corporation (GPU).
There is a divided system of decision-making within GPU and its
subsidiaries.
While the utility has legal responsibility for a wide
range of fundamental decisions, from plant design to operator training,some utilities have to rely heavily on the expertise of their suppliers
and on the Nuclear Regulatory Commission. Our report contains a numberof examples where this divided responsibility, in the case of TMI, may
have led to less than optimal design and operating practices. For
example, we have received contradictory testimony on how the criteria
under which the containment building isolates were selected. Similarly,
the design of the control room seems to have been a compromise among of
the utility, its parent company, the architect-engineer, and the nuclear
steam system supplier (with very little attention from the NRC). But
the clearest example of the shortcomings of divided responsibility is
the area of operator training.
The legal responsibility for training operators and supervisors forsafe operation of nuclear power plants rests with the utility. However,
Met Ed, the GPU subsidiary which operates TMI, did not have sufficientexpertise to carry out this training program without outside help.
They, therefore, contracted with Babcock & Wilcox, supplier of thenuclear steam system, for various portions of this training program
While B&W has substantial expertise, they had no responsibility for thequality of the total training program, only for carrying out the
And coordination between the training programs ofcontracted portion.
the two companies was extremely loose. For example, the B&W instructors
were not aware of the precise operating procedures in effect at theplant.
22

OVERVIEW

A key tool in the B&W training is a "simulator," which is a mockcontrol console that can reproduce realistically events that happen
within a power plant. The simulator differs in certain significant ways
from the actual control console. Also, the simulator was notprogrammed, prior to March 28, to reproduce the conditions that
confronted the operators during the accident.
We found that at both companies, those most knowledgeable about theworkings of the nuclear power plant have little communication with those
responsible for operator training, and therefore, the content of the
instructional program does not lead to sufficient understanding ofreactor systems.
It is our conclusion that the role that the NRC plays in monitoring
operator training contributes little and may actually aggravate theproblem.
NRC has a limited staff for supervising operator licensing,and many of these do not have actual experience in power plants.
Therefore, NRC activities are limited to the administration of fairly
routine licensing examinations and the spotchecking of requalification
exams and training programs. In evaluating the training of operators tocarry out emergency procedures, NRC failed to recognize basic faults inthe procedures in existence at TMI. Since the utility has the tendency
of equating the passing of an NRC examination with the satisfactory
training of operators, NRC may be perpetuating a level of mediocrity.
The way that NRC evaluates the safety of proposed plants during thelicensing process has a most unfortunate impact on the way operators are
Since during the licensing process applicants for licenses
trained.
concentrate on the consequences of single failures, there is no attemptin the training program to prepare operators for accidents in which twosystems fail independently of each other.
There were significant deficiencies in the management of the TMI-2
plant.
Shift foremen were burdened with paper work not relevant tosupervision and could not adequately fulfill their supervisory roles.
There was no systematic check on the status of the plant and the line-upof valves when shifts changed. Surveillance procedures were notadequately supervised.
And there were weaknesses in the program ofquality assurance and control.
We agree that the utility that operates a nuclear power plant mustbe held legally responsible for the fundamental design and procedures
However, the analysis of this particularthat assure nuclear safety.
accident raises the serious question of whether all electric utilities
automatically have the necessary technical expertise and managerial
capabilities for administering such a dangerous high-technology plant.
We, therefore, recommend the development of higher standards oforganization and management that a company must meet before it isgranted a license to operate a nuclear power plant.

23

OVERVIEW
THE TRANSITION
We recognize that even with the most expeditious process for
implementation, recommendations as sweeping as ours will take asignificant amount of time to implement. Therefore, the Commission had
to face the issue of what should be done in the interim with plants thatare currently operating and those that are going through the licensing
process.
The Commission unanimously voted:
Because safety measures to afford better protection
for the affected population can be drawn from thehigh standards for plant safety recommended in thisreport, the NRC or its successor should, on a case-by-casebasis, before issuing a new construction permit oroperating license:(a) assess the need to introduce
new safety improvements recommended in this report,
and in NRC and industry studies; (b) review,
considering the recommendations set forth in thisreport, the competency of the prospective operating
licensee to manage the plant and the adequacy of its
training program for operating personnel; and(c) condition licensing upon review and approval of thestate and local emergency plans.
A WARNING
During the time that our Commission conducted its investigation, anumber of other reports appeared with recommendations for improved
While we are generally aware of thesafety in nuclear power plants.
nature of these recommendations, we have not attempted a systematic
analysis of them. Insofar as other agencies may have reached similar
conclusions and proposed similar remedies, several groups arriving at
the same conclusion should reinforce the weight of these conclusions.
But we have an overwhelming concern about some of the reports wehave seen so far. While many of the proposed "fixes" seem totally
appropriate, they do not come to grips with what we consider to be thebasic problem.
We have stated that fundamental changes must occur inorganizations, procedures, and, above all, in the attitudes of people.
No amount of technical "fixes" will cure this underlying problem. There
have been many previous recommendations for greater safety for nuclear
power plants, which have had limited impact.
What we consider crucial
is whether the proposed improvements are carried out by the sameorganizations (unchanged), with the same kinds of practices and the same
attitudes that were prevalent prior to the accident. As long as
proposed improvements are carried out in a "business as usual"
atmosphere, the fundamental changes necessitated by the accident atThree Mile Island cannot be realized.

24

OVERVIEW
We believe that we have conscientiously carried out the mandate of
the President of the United States, within our limits as human beings
and within the limitations of the time allowed us. We have not found a
magic formula that would guarantee that there will be no serious futurenuclear accidents.
Nor have we come up with a detailed blueprint for
nuclear safety.
And our recommendations will require great efforts byothers to translate them into effective plans.
Nevertheless, we feel that our findings and recommendations are ofvital importance for the future of nuclear power. We are convinced
that, unless portions of the industry and its regulatory agency undergo
fundamental changes, they will over time totally destroy publicconfidence and, hence, they will be responsible for the elimination of
nuclear power as a viable source of energy.

25

A.

Assessment of Significant Events

B.

Health Effects

C.

Public HealthD.

Emergency Response

E.

The Utility and Its SuppliersF.

Training of Operating Personnel

G.

The Nuclear Regulatory Commission

H.

The Public's Right to Information

26

COMMISSIONFINDINGSThe President's Commission on the Accident at Three Mile
Island, after conducting a study and investigation into the eventsof that accident and the conditions existing prior to the accident,
finds and concludes*/:
To prevent nuclear accidents as serious as Three Mile Island,
fundamental changes will be necessary in the organization,
procedures, and practices -- and above all -- in the attitudesof the Nuclear Regulatory Commission and, to the extent that theinstitutions we investigated are typical, of the nuclear
industry.
A.

ASSESSMENT OF SIGNIFICANT EVENTS

1.
The accident at Three Mile Island (TMI) occurred as aresult of a series of human, institutional, and mechanical failures.
2.
Equipment failures initiated the events of March 28 andcontributed to the failure of operating personnel (operators, engineers, and supervisors) to recognize the actual conditions of the
Their training was deficient and left them unprepared forplant.
the events that took place. (See finding F.) These operating
personnel made some improper decisions, took some improper actions,and failed to take some correct actions, causing what should havebeen a minor incident to develop into the TMI-2 accident.

*/ "Supplemental Views" from Commissioners are available and will be
included in the permanent edition of the Commission's report.

27

COMMISSION FINDINGSThe pilot-operated relief valve (PORV) at the top of the3.
pressurizer opened as expected when pressure rose but failed toclose when pressure decreased, thereby creating an opening in the
primary coolant system -- a small-break loss-of-coolant accident(LOCA).*/ The PORV indicator light in the control room showed onlythat the signal had been sent to close the PORV rather than the factthat the PORV remained open. The operators, relying on theindicator light and believing that the PORV had closed, did not heed
other indications and were unaware of the PORV failure; the LOCA
continued for over 2 hours. The TMI-2 emergency procedure for astuck-open PORV did not state that unless the PORV block valve wasclosed, a LOCA would exist. Prior to TMI, the NRC had paid
insufficient attention to LOCAs of this size and the probability of
their occurrence in licensing reviews. Instead, the NRC focused
most of its attention on large-break LOCAs.
The high pressure injection system (HPI) -- a major design4.
safety system -- came on automatically. However, the operators wereconditioned to maintain the specified water level in the pressurizer
and were concerned that the plant was "going solid," that is, filled
Therefore, they cut back HPI from 1,000 gallons
with water.
per minute to less than 100 gallons per minute. For extended
periods on March 28, HPI was either not operating or operating at anThis led to much of the core being uncovered for
insufficient rate.
extended periods on March 28 and resulted in severe damage to the
If the HPI had not been throttled, core damage would havecore.
been prevented in spite of a stuck-open PORV.
TMI management and engineering personnel also had
5.
difficulty in analyzing events. Even after supervisory personnel
took charge, significant delays occurred before core damage was
fully recognized, and stable cooling of the core was achieved.
Some of the key TMI-2 operating and emergency procedures
6.
in use on March 28 were inadequate, including the procedures for a
LOCA and for pressurizer operation. Deficiencies in theseprocedures could cause operator confusion or incorrect action.

For a definition of loss-of-coolant accident and other*/technical terms used in the Commission's report, see the Glossary at
the back of this volume.

28

COMMISSION FINDINGS
Several earlier warnings that operators needed clear
7.
instructions for dealing with events like those during the TMI
accident had been disregarded by Babcock & Wilcox (B&W) and the
Nuclear Regulatory Commission (NRC).
a.
In September 1977, an incident occured at theDavis-Besse plant, also equipped with a B&W reactor. During thatincident, a PORV stuck open and pressurizer level increased, whilepressure fell.
Although there were no serious consequences of thatincident, operators had improperly interfered with the HPI,
apparently relying on rising pressurizer level.
The Davis-Besse
plant had been operating at only 9 percent power and the PORV block
valve was closed approximately 20 minutes after the PORV stuck open.
That incident was investigated by both B&W and the NRC, but noinformation calling attention to the correct operator actions wasprovided to utilities prior to the TMI accident. A B&W engineer had
stated in an internal B&W memorandum written more than a year before
the TMI accident that if the Davis-Besse event had occurred in areactor operating at full power, "it is quite possible, perhaps
probable, that core uncovery and possible fuel damage would haveoccurred."b.
An NRC official in January 1978 pointed out thelikelihood for erroneous operator action in a TMI-type incident.
The NRC did not notify utilities prior to the accident.
c.
A Tennesse Valley Authority (TVA) engineer analyzed
the problem of rising pressurizer level and falling pressure morethan a year before the accident. His analysis was provided to B&W,
NRC, and the Advisory Committee on Reactor Safeguards. Again no
notification was given to utilities prior to the accident.
The control room was not adequately designed with the8.
management of an accident in mind. (See also finding G.8.e.) For
example:Burns and Roe, the TMI-2 architect-engineer, hada.
never systematically evaluated control room design in the context ofa serious accident to see how well it would serve in emergency
conditions.
b.
The information was presented in a manner which could
confuse operators:
Over 100 alarms went off in the early(i)stages of the accident with no way of suppressing
the unimportant ones and identifying the important
The danger of having too many alarms wasones.
recognized by Burns and Roe during the design
stage, but the problem was never resolved.
The arrangement of controls and(ii)
indicators was not well thought out. Some key
indicators relevant to the accident were on theback of the control panel.

29

COMMISSION FINDINGS(iii)
Several instruments went off-scale
during the course of the accident, depriving theoperators of highly significant diagnostic
information.
These instruments were not designed
to follow the course of an accident.
(iv)
The computer printer registering alarms
was running more than 2-k hours behind the eventsand at one point jammed, thereby losing valuable
information.
After an April 1978 incident, a TMI-2 control roomc.
operator complained to his superiors about problems with the control
room. No corrective action was taken by the utility.
9.
In addition to the normal instrumentation present in thecontrol room at the time of the accident, TMI-2 was equipped with a
special data recorder that B&W had temporarily installed during theplant start-up and never removed. This data recorder, called areactimeter, preserved a large amount of information useful inpost-accident analysis.
This type of data recorder was not required
as standard equipment by the NRC.
10. Those managing the accident were unprepared for thesignificant amount of hydrogen generated during the accident.
Indeed, during the TMI-2 licensing process which concentrated onlarge-break LOCAs, the utility represented and the NRC agreed thatin the event of a large-break LOCA, the hydrogen concentration incontainment would not be significant for a period of weeks. In thefirst 10 hours of the TMI accident (a small-break LOCA), enoughhydrogen was produced in the core by a reaction between steam andthe zirconium cladding and then released to containment to produce aburn or an explosion that caused pressure to increase by 28 pounds
per square inch in the containment building. Thus, TMI illustrated
a situation where NRC emphasis on large breaks did not cover theeffects observed in a smaller accident.
Iodine filters in the auxiliary and fuel handling
11.
buildings did not perform as designed because the charcoal filtering
capacity was apparently partially expended due to improper use
before the accident.
Required testing of filter effectiveness forthe fuel handling building had been waived by the NRC. There wereno testing requirements to verify auxiliary building filter
effectiveness.
The nature and extent of damage to the core is not likely
12.
to be known with assurance until the core materials are recovered
and carefully examined. However:a.
We estimate that there were failures in the cladding
around 90 percent of the fuel rods. The interaction of the very hot
cladding with water generated somewhere between 1,000 and 1,300
pounds of hydrogen gas and converted 44 to 63 percent of thezirconium to relatively weak zirconium oxide. As a result ofoxidation and embrittlement of the fuel rod cladding, several feet

30

COMMISSION FINDINGSof the upper part of the core fell into the gaps between the fuelrods, causing partial blocking of the flow of steam or water that
could remove heat from the damaged fuel.
b.
Fuel temperatures may have exceeded 4,000°F in theupper 30 to 40 percent of the core (approximately 30 to 40 tons offuel). Temperatures in parts of the damaged fuel that were noteffectively cooled by steam may have reached the melting point of
the uranium oxide fuel, about 5,200°F.
c.
An NRC study suggests that some of the fuel may havebecome liquid at temperatures above 3,500°F by dissolving in azirconium-zirconium oxide mixture.
The study estimates that theamount of fuel that may have melted by this process is from zero toa few tons. An independent analysis by Argonne National Laboratory
suggests that the formation of such a mixture was unlikely.
d.
Substantial fractions of the material in the reactor
control rods melted.
e.
There is no indication that any core material madecontact with the steel pressure vessel at a temperature above themelting point of steel (2,800°F).
13.
The total release of radioactivity to the environment fromMarch 28 through April 27 has been established as 13 to 17 curies ofiodine and 2.4 million to 13 million curies of noble gases. (Thehealth effects of the radiation released are described infinding B.)
a.
Five hundred thousand times as much radioactive
iodine (7.5 million curies) was retained in the primary loop. On
April 1, 10.6 million curies of iodine were retained in thecontainment building's water and about 36,000 curies in thecontainment atmosphere. Four million curies were in the auxiliarybuilding tanks.
Almost all of .the radioactive iodine released fromthe fuel was retained in the primary system, containment, and theauxiliary building.
Since the accident, most of the short-lived
radioactive iodine has decayed and is no longer a danger.
b.
No detectable amounts of the long-lived radioactive
cesium and strontium escaped to the environment, althoughconsiderable quantities of each escaped from the fuel to the waterof the primary system, the containment building, and the auxiliarybuilding tanks.
c.
Most radioactivity escaping to the environment was in
the form of fission gases transported through the coolant let-down/
make-up system into the auxiliary building and through the building
filters and the vent header to the outside atmosphere.
d.
The major release of radioactivity on the morning ofMarch 30 was caused by the controlled, planned venting of the
make-up tank into the vent header. The header was known to have a
leak.

31

Cbm1vTFpLWoHrR456icOSkuI9hea$wtfq(EUdAlN.sx8n7gzyM0j
Low

MediumHigh(Millions of dollars)

Refurbish TMI-2

Emergency Management
Replacement Power'•/
Plant Refurbishment
Total**/

$

120
678
249

$1,047

$

160
966
306

$1,432

$

225
1,128
503

$1,856The low case assumes TMI-2 will be returned to service inJanuary 1983, the medium assumes January 1984, and the high assumes
January 1985.
%L/

The costs associated with health effects have been deleted fromthis table. The costs projected by the study had a minimal effect
The Commission believes that theon the total costs projected.
analysis of health effects costs was insufficent to reach theconclusion set out in the study.

32

COMMISSION FINDINGS
17. The Commission tried to determine what would have happened
if certain additional events had occurred during the accident. Fora discussion of these scenarios, see the Commission Overview and thetechnical staff analysis report on "Alternative Event Sequences."

33

COMMISSION FINDINGSB.

HEALTH EFFECTS
1.

Based on available dosimetric and demographic information:a.
It is estimated that between March 28 and April 15,
the collective dose resulting from the radioactivity released to the
population living within a 50-mile radius of the plant was approximately 2,000 person-rems.
The estimated annual collective dose tothis population from natural background radiation is about 240,000
person-rems.
Thus, the increment of radiation dose to persons
living within a 50-mile radius due to the accident was somewhat lessthan one percent of the annual background level. The average doseto a person living within 5 miles of the nuclear plant wascalculated to be about 10 percent of annual background radiation andprobably was less.
b.
The maximum estimated radiation dose received by any
one individual in the off-site general population (excluding theplant workers) during the accident was 70 millirems. On the basisof present scientific knowledge, the radiation doses received by thegeneral population as a result of exposure to the radioactivity
released during the accident were so small that there will be no
detectable additional cases of cancer, developmental abnormalities,
or genetic ill-health as a consequence of the accident at TMI.
c.
During the period from March 28 to June 30, three TMI
workers received radiation doses of about 3 to 4 rems; these levels
exceeded the NRC maximum permissible quarterly dose of 3 rems.
d.
The process of recovery and cleanup presents
additional sources of possible radiation exposure to the workers andthe general population.
2.
There were deficiencies in instrumentation for measuring
the radioactivity released, particularly during the early stages of
the accident.
However, these deficiencies did not affect theCommission staff's ability to estimate the radiation doses or healtheffects resulting from the accident.
34

COMMISSION FINDINGS
3.
The health effects of radiation dose levels of a few remsor less are not known. Estimates of the potential health effects of
the TMI accident are based on extrapolations from the known healtheffects of higher levels of radiation.
4.
The major health effect of the accident appears to havebeen on the mental health of the people living in the region ofThree Mile Island and of the workers at TMI. There was immediate,short-lived mental distress produced by the accident among certain
groups of the general population living within 20 miles of TMI. The
highest levels of distress were found among adults a) living within
5 miles of TMI, or b) with preschool children; and among teenagersa) living within 5 miles of TMI, b) with preschool siblings, or c)whose families left the area. Workers at TMI experienced more
distress than workers at another plant studied for comparison
purposes. This distress was higher among the nonsupervisory
employees and continued in the months following the accident.

35

COMMISSION FINDINGSC.

PUBLIC HEALTHThe Nuclear Regulatory Commission has primary1.
responsibility and regulatory authority for health and safetymeasures as they relate to the operation of commercial nuclear
plants. While the NRC has certain requirements in connection withradiation exposure and medical monitoring of workers at nuclear
plants, it has no requirements for medical examination of workers
other than licensed reactor operators, and even those examinations
are only performed to assure that the operators do not have physicalor mental conditions that might impair their ability to perform
Metropolitan Edison's (Met Ed) administrative
their jobs safely.
procedures go beyond this NRC requirement and provide that allradiation workers receive routine medical examinations to assess any
The NRC only requires
possible radiation-related illnesses.
monitoring and reporting of radiation exposure for workers who, inthe utility's view, are likely to receive doses beyond NRC-specified
levels.
Met Ed does not keep, and the NRC does not require it toreport, a record of the total radiation exposure of workers fromboth occupational and nonoccupational (for example, medical anddental) sources.
2. The Public Health Service agencies of the U.S. Department
of Health, Education, and Welfare (HEW), ^ / whose sole mission isprotection and promotion of the public health, have very limited
responsibilities with respect to radiological health mattersrelating to the location, construction, and routine operation ofcommercial nuclear power plants.
3.
Although there were designated channels of communicationand specific responsibilities assigned for federal agencies
responding to the radiological emergency at TMI (for example,
Interagency Radiological Assistance Plan), the existence of thesechannels and responsibilities was generally unknown to manyhigh-level federal officials.
In several instances during thecourse of the accident, some federal agencies were unaware of what
other federal agencies were doing in providing support personnel andresources.

Now the U.S. Department of Health and Human Services.
36

COMMISSION FINDINGS
4.
Research on the biological effects of ionizing radiationis conducted and/or sponsored by a number of federal agencies. In
fiscal year 1978, the federal government spent approximately$76.5 million on such research. More than 60 percent of thisfunding was provided by the U.S. Department of Energy. With the
exception of potassium iodide, there are no drugs presently approvedby the Food and Drug Administration for the prevention or mitigationof adverse effects of ionizing radiation.
5.
States have primary responsibility for protecting thehealth and safety of their citizens. Pennsylvania public healthofficials and health-care providers in the TMI area did not havesufficient resources to respond to the potentially serious healthconsequences of the accident at TMI. Responsibility forradiological protection in Pennsylvania rests with the Department ofEnvironmental Resources (DER). At the time of the accident, thePennsylvania Department of Health was not organized to respond toradiological emergencies, and maintained no formal liaison with DER
on radiological health matters.
6.
During the accident, TMI-area hospital administrators
found no one at the state level with authority to recommend when toevacuate patients and when to resume normal admitting procedures.
The Pennsylvania Secretary of Health viewed his department's rolewith respect to area hospitals as informational, not advisory.
7.
During the first days of the accident, Met Ed did not
notify its physicians under contract who would have been responsible
for the on-site treatment of injured, contaminated workers during
the accident. The emergency radiological medical care training
provided to these physicians to provide on-site emergency care tosuch workers was inadequate.
8.
Met Ed experienced several radiation protection problems
during the accident: a) the emergency control center for healthphysics operations and the analytical laboratory to be used inemergencies was located in an area that became uninhabitable in theearly hours of the accident; b) there was a shortage of respirators;
and c) there was an inadequate supply of uncontaminated air.
9.
NRC regulations on health physics education of nuclear
power plant workers leaves the details of such things as course
content, frequency, and attendance to the discretion of thelicensee, subject to NRC inspection. Similarly, NRC regulations forenvironmental radiological monitoring leaves the details and methodsof how these requirements are to be implemented (for example, typesof dosimeters, kind of sample analysis) to the discretion of thelicensee, subject to NRC inspection and approval.

37

COMMISSION FINDINGSD.

EMERGENCY RESPONSE

1.
Planning for the protection of the public in the event ofa radiological release that extends beyond the boundary of TMI was
highly complex.
It involved the utility and government agencies atthe local, state, and federal levels. That complexity posed
problems in the case of the accident at Three Mile Island; some of
the written plans that existed had not been coordinated andcontained different systems for classifying accidents and different
guidelines for notifying government officials.
2.
In approving sites for reactors, the NRC has required
licensees to plan for off-site consequences of radioactive releases
only within the "low population zone" (LPZ), an area containing"residents, the total number and density of which are such that
there is a reasonable probability that appropriate protective
measures could be taken in their behalf in the event of a serious
accident." As calculated for the design-basis accident for TMI-2,
this zone was a 2-mile radius.
Emergency planning had a low priority in the NRC and the3.
AEC before it. There is evidence that the reasons for this included
their confidence in designed reactor safeguards and their desire to
avoid raising public concern about the safety of nuclear power.
4.
The NRC has not made the existence of a state emergency or
evacuation plan a condition for plant licensing. A state may voluntarily submit a response plan to NRC for concurrence, and if theplan meets NRC guidelines -- which do not have the force of law -the state receives a formal letter of concurrence. At the time of
the accident, Pennsylvania did not have an NRC concurred-in plan.
The NRC concurrence program has been called ineffective by federal
and state emergency preparedness officials.
The utility has the responsibility to prevent or to5.
mitigate off-site radiation releases and to notify the government
agencies designated in its emergency plan in the event that an
emergency is declared.
Federal, state, and local agencies are
responsible for off-site response to radiation releases. At the38

COMMISSION FINDINGS
time of the TMI accident, the local and county governments had theprimary action role once notified of the emergency. None of thelocal communities within the 5-mile radius of the plant had emergency
plans, and the existing county plans did not include detailed evacuationplans.
6.
At all levels of government, planning for the off-site
consequences of radiological emergencies at nuclear power plants has
been characterized by a lack of coordination and urgency. For
example, a federal response plan in preparation since 1974 by federal
emergency preparedness agencies was unfinished at the time of theaccident because of an interagency jurisdictional dispute and lackof communication. Pennsylvania did not begin to develop a radiologicalemergency plan until 1975, even though nuclear power plants had been
operating within its borders for at least a year prior to that time.
People who attempted to generate interest in radiological emergency
planning at the local level near TMI found local officials apathetic.
Part of the reason for this was the attitude fostered by the NRC
regulatory approach, and by Met Ed at the local level, thatradiological accidents having off-site consequences beyond the LPZ
were so unlikely as not to be of serious concern.
7.
Interaction among NRC, Met Ed, and state and local
emergency organizations in the development, review, and drill of
emergency plans was insufficient to ensure an adequate level of
preparedness for a serious radiological incident at TMI.
8.
Although NRC personnel were on-site within hours of thedeclaration of a site emergency and were in constant contact withthe utility, the NRC was not able to determine and to understand thetrue seriousness and nature of the accident for about 2 days, when
the fact of extensive core damage and the existence of the hydrogen
bubble were generally recognized within NRC.
9.
During the first 2-/ days of the accident, communications
between the NRC Incident Response Center in Bethesda, Maryland,
where the senior management was located, and the site were such that
senior management officials found it extremely difficult to obtain
up-to-date information.
Communications were so poor on Friday
morning that the senior management could not and did not develop a
clear understanding of conditions at the site. As a result, anevacuation was recommended to the state by the NRC senior staff on
the basis of fragmentary and partially erroneous information.
Communications did not improve until Harold Denton, designated thesole source of information, arrived on the site and communicatedwith NRC headquarters, the Governor's office, and the White House by
White House communications line.
10. The reality of possible evacuation was quite different
from the theoretical planning requirements imposed by the NRC andPennsylvania before the accident.
The 5-mile emergency plans weredeveloped according to a Pennsylvania requirement for emergency
planning within a 5-mile radius of nuclear power plants. The
Pennsylvania requirement was stricter than that prescribed by NRC,
39

COMMISSION FINDINGS
which only required TMI to have a plan for a radius to 2 miles.
(See finding D.2.) It is known that the consequences of a
postulated major release to the atmosphere from a reactor accident
could lead to significant doses of radiation being received manytens of miles from the site of the accident. At TMI-2, although theradiation releases were significantly lower than the design-basis
accident, evacuation was being considered for distances much greaterthan 2 miles. During the TMI accident, NRC believed that theconsequences of the accident might extend far beyond the 2- orAs a result, evacuation plans were hurriedly
5-mile radius.
developed for distances of 10 and 20 miles from the plant.
During the most critical phase of the accident, the NRC
11.
was working under extreme pressure in an atmosphere of uncertainty.
The NRC staff was confronted with problems it had never analyzed
before and for which it had no immediate solutions. One result of
these conditions was the calculational errors concerning thehydrogen bubble, which caused the NRC to misunderstand the true
conditions in the reactor for nearly 3 days.
12. On Friday and Saturday, certain NRC officials incorrectly
concluded that a hydrogen bubble in the reactor vessel would soon
contain enough oxygen to burn or explode. Ignoring correct
information supplied by a B&W employee and certain members of its
own staff, NRC relied instead upon incorrect information supplied byother members of its staff and by others that sufficient oxygen was
being formed from water radiolysis to reach a concentration
sufficient for a burn or explosion. Based on this information, the
NRC commissioners began formulating new recommendations forevacuation.
On Sunday, NRC staffers obtained information fromseveral national laboratories and from General Electric andWestinghouse that sufficient oxygen could not form. The Sunday
information ended the concern about oxygen formation and evacuation.
This incident suggests that NRC lacks sufficient knowledge andexpertise in water radiolysis.
13. The role of the NRC commissioners and theirdecision-making process during the accident were ill-defined.
Although the commissioners on Friday assumed responsibility formaking recommendations to the Governor concerning protective action,
there was no apparent procedure by which issues and staff
recommendations were explored and resolved. The commissioners werepreoccupied with matters such as the details of evacuation planningand the drafting of a press release.
14. Existing emergency plans were not designed to meet thedemands of a protracted crisis. The plans had no mechanisms forestablishing reliable communications among the on-site and theseveral off-site organizations responsible for various aspects ofthe emergency response.
There were no hospitals within 5 miles of TMI, but there
15.
were several hospitals within the expanded, proposed evacuation
zones. The NRC estimated that it would be able to give officials a
few hours "lead time" for evacuation. But hospital administrators

40

COMMISSION FINDINGS
estimated they would need substantially more time to evacuatepatients.

16. During the TMI accident, the actual radiation levels
outside the plant were low, but there was uncertainty about thepossibility of serious releases on short notice. Federal and state
officials disagreed about the nature of the information on which tobase evacuation decisions and other protective actions during theSome officials based their decisions on actual radiation
emergency.
exposure levels, while others based their decisions on concerns
about potential releases of large amounts of radioactivity. For
example, the Pennsylvania Bureau of Radiation Protection told theGovernor on Friday that radiation levels indicated that noprotective action of any kind was required; on that same morning,
NRC Chairman Hendrie recommended that pregnant women and young
children be advised to leave the area near the plant because of his
concern about possible releases of radioactivity.
17. At approximately 12:30 p.m., March 30, Governor Thornburgh
advised pregnant women and preschool aged children to leave the area
within a 5-mile radius of TMI until further notice. A substantial
number of other persons, including health professionals, voluntarily
left the area around the plant during the weekend of March 30
through April 1. The advisory to pregnant women and preschool
children was lifted on April 9.
Throughout the accident, the Pennsylvania Emergency
18.
Management Agency (PEMA) received reports concerning conditions at
the site from the Bureau of Radiation Protection. During the first
2 days of the accident, however, the director of PEMA also received
background information on the status of the plant from theGovernor's office by attending meetings and press conferences andrelayed that information to county organizations, which, in turn,informed the local civil defense directors. Starting Saturday, thePEMA director was no longer included in these meetings with theresult that PEMA and county and local civil defense organizations
had to rely primarily on the news media for information about
conditions at the site. They found this an unsatisfactory source of
information and believed that this arrangement compromised theireffectiveness in responding to the accident.
The TMI emergency plan did not require the utility to
19.
notify state or local health authorities in the event of aradiological accident. (See also finding C.7.)
For over 25 years, the use of blocking agents such as
20.
potassium iodide to prevent the accumulation of radioiodine in the
thyroid gland has been known. The effectiveness of potassium iodide
administration for thyroid gland protection in the event of releasesof radioiodine was recognized by the National Council on Radiation
Protection and Measurement in 1977. The Food and Drug
Administration authorized use of potassium iodide as athyroid-blocking agent for the general public in December 1978.
However, at the time of the TMI accident, potassium iodide for thisuse was not commercially available in the United States in41

COMMISSION FINDINGS
quantities sufficient for the population within a 20-mile radius of
TMI. At the time of the accident, Met Ed had no supply of potassium
iodide on-site.
A crash effort by the federal government andprivate industry resulted in delivery of substantial supplies ofpotassium iodide to Pennsylvania within 2 days of the decision to
obtain such supplies.

42

COMMISSION FINDINGSE.

THE UTILITY AND ITS SUPPLIERS

1.
In a number of important cases, General Public Utilities
Corporation (GPU), Met Ed, and B&W failed to acquire enoughinformation about safety problems, failed to analyze adequately what
information they did acquire, or failed to act on that information.
Thus, there was a serious lack of communication about several
critical safety matters within and among the companies involved in
the building and operation of the TMI-2 plant. A similar problem
existed in the NRC. (See finding G.)a.
The September 1977 incident at Davis-Besse, anotherplant with a B&W reactor, foreshadowed several aspects of the TMI-2
accident. A serious warning by a senior engineer at B&W that more
precise instructions be given to operators "fell between thecracks." This warning, issued 13 months before the TMI-2 accident,
if heeded, could have prevented the accident. (See alsofinding A.7.a.)b.
Nine times before the TMI accident, PORVs stuck open
at B&W plants. B&W did not inform its customers of these failures,
nor did it highlight them in its own training program so that
operators would be aware that such a failure causes a small-breakLOCA.
c.
A report by an engineer at TVA questioning how
operators might respond to rising pressurizer level and fallingpressure was sent to B&W in April 1978. B&W took 9 months to
respond and never advised its utility customers of the concern
expressed in the report. The concern was similar to the one which
B&W itself had identified from the Davis-Besse incident.
d.
TMI-2 had repeated problems with the condensate
polishers. During the 18-month period before the accident, noeffective steps were taken to correct these problems. These
polishers probably initiated the March 28 sequence of events.
e.
The TMI-2 operators had never had specific training
about the dangers of saturation conditions in the core, although
they were generally familiar with the concept. Although Met Ed

43

COMMISSION FINDINGS
believed saturation had occurred in an incident a year before theaccident that could have led to core uncovery, its hazards were not
When saturation occurred again onemphasized to the operators.
March 28, operators did not recognize the significance of that fact
and take corrective action promptly.
After an incident at TMI-2 a year earlier duringf.
which the PORV stuck open, an indicator light was installed in theThat light showed only that a signal had been sent tocontrol room.
close the valve -- it did not show whether the valve was actuallyclosed -- and this contributed to the confusion during the accident.
(See finding A.3.)
Timely attention to all of these factors probably would have
prevented the accident.
2.
The GPU Service Corporation (GPUSC) had final
responsibility for design of the plant. However, by its own
account, it lacked the staff or expertise in certain areas toOnce construction was complete,discharge that responsibility.
GPUSC turned the plant over to Met Ed to run, but Met Ed did nothave sufficient knowledge, expertise, and personnel to operate theplant or maintain it adequately.
Responsibility for management decisions was divided among3.
GPU recognized in early 1977 that
the TMI site, Met Ed, and GPU.
integration of operating responsibility into one organization was
A management audit by Booz, Allen, and Hamilton
desirable.
completed in the spring of 1977 recommended clarifying andreevaluating the roles of GPUSC and Met Ed in the design andconstruction of new facilities; strengthening communications between
GPUSC and Met Ed; and establishing minimum standards for the safe
operation of GPU's nuclear plants. However, integration ofmanagement did not occur until after the accident.
4.
The Met Ed management systems, procedures, and practices
did not provide Met Ed a firm understanding of TMI's operations, norwere effective systems of checks and balances in use.
Met Ed had a plan for a quality assurance programa.
that met NRC requirements. The NRC requirements, however, were
inadequate because they did not require quality assurance programs
to be applied to the plant as a whole, but rather only to systems
classified as "safety-related." Neither the PORV nor the condensate
polishers were classified as "safety-related." In addition, the NRC
did not require the level of independent review (i.e., outside ofline management) normally found in the quality assurance programs ofsafety-critical industries.
There was no requirement for an independent (i.e.,b.
outside of line management) safety assessment of operatingprocedures.
Independent audit of the performance of surveillance
procedures was required only every 2 years.
44

COMMISSION FINDINGSMet Ed's implementation of its own quality assurancec.
plan was found to contain significant deficiencies by the Commission
staff and in an NRC post-accident audit of TMI-2. For example:
There were not enough inspectors to do(i)
the inspections required under the Met Ed plan.
The NRC audit reported deficiencies in(ii)
maintaining "as built" drawings and in thepurchasing of "safety-related" equipment without
quality controls.
Although all plant procedures were(iii)
required to be reviewed every 2 years, there wasno plan for such a review and no review had infact been made of those TMI-2 procedures that weremore than 2 years old.
Although such inspections were required,(iv)
Met Ed had not scheduled or conducted any
inspections of materials, components, or equipment
in storage.
(v)
There were deficiencies in thereporting, analysis, and resolution of problems in"safety-related" equipment and other events
required to be reported to the NRC.
Independent assessment of general plant(vi)
operations was minimal.
areas as:d.

Met Ed did not go beyond NRC requirements in such
Requiring reporting, resolution, and(i)trending of problems in plant equipment andprocedures which were not "safety-related."
Applying its quality assurance program(ii)
to the operation of non-"safety-related" equipment
and systems vital to plant operation, consistent
with the importance of those systems to safety.
For example, no quality assurance review was given
to radiation monitoring equipment, control rod
drive mechanisms, hydrogen recombiners, the PORV,
or condensate polishers. In addition, Met Ed'squality assurance program was not applied to themaintenance or the procedures associated with suchnon-"safety-related" equipment.

As a result of these deficiencies, the safe operation of theTMI-2 plant was impaired.
Utility management did not require attention to detail as
5.
a way of life at Three Mile Island. For example:

45

COMMISSION FINDINGSa.
Management permitted operation of the plant with anumber of poor control room practices:(i)
A shift supervisor testified that there
had never been less than 52 alarms lit in thecontrol room.
(ii)
TMI Commission staff and NRC inspections
noted a large number of control room instruments
out of calibration and tags hanging on the
instrument panel indicating equipment out ofservice.
Operators testified that one of thesetags obscured one of the emergency feedwater block
control valve indicator lights.
(iii)
When shifts changed in the control room,
there was no systematic check on the status of theplant and the line-up of valves.
b.
There were deficiencies in the review, approval, andimplementation of TMI-2 plant procedures.
(i)
Although Met Ed procedures required closing
the PORV block valve when temperatures in the
tailpipe exceeded 130°F, the block valve had notbeen closed at the time of the accident eventhough temperatures had been well above 130 ° F in
the tailpipe for weeks.
(ii)
Operators were not given adequate
information about temperatures to be expected in
the PORV tailpipe after the PORV opened.
(iii) A 1978 B&W analysis of a certain kind ofsmall-break LOCA was misinterpreted by Met Ed.
That misinterpretation was incorporated by Met Ed
into the LOCA emergency procedure available at thetime of the accident.
(iv) Operating and emergency procedures that had
been approved by Met Ed and were in use at thetime of the accident contained many minor
substantive errors, typographical errors, andimprecise or sloppy terminology. Some were
inadequate.
(See finding A.6.)(v) A 1978 revision in the TMI-2 surveillance
procedure for the emergency feedwater block valves
violated TMI-2's technical specifications, but noone realized it at the time. The approval of therevision in the surveillance procedure was notdone according to Met Ed's own administrative
procedures.
46

COMMISSION FINDINGS(vi) Performance of surveillance tests was notadequately verified to be sure that the procedures
were followed correctly.
On the day of theaccident, emergency feedwater block valves whichshould have been open were closed. They may havebeen left closed during a surveillance test 2 days
earlier.
c.

There were deficiencies in maintenance:(i) After the accident, valves in the TMI-1
containment building exhibited long-term lack ofmaintenance.
Boron stalactites more than a footlong hung from the valves and stalagmites hadbuilt up from the floor.
(ii) Review of equipment history for the 6 months
prior to the accident showed that a number of
equipment items that figured in the accident had
had a poor maintenance history without adequate
corrective action.
These included the pressurizer
level transmitter, the hydrogen recombiner,pressurizer heaters, make-up pump switches, andthe condensate polishers.
(iii) Despite a history of problems with thecondensate polishers, procedures were not changed
to ensure that operators would bypass thepolishers during maintenance operations to protect
the plant from a possible malfunction of thepolisher.

d.
After the accident, radiological control practices
were observed to be deficient. Contaminated and potentiallycontaminated equipment was found in uncontrolled areas of theauxiliary building.
e.
Training of operators and supervisors did not give
sufficient emphasis to a fundamental understanding of the reactor.
There was no comprehensive evaluation of operator performance on the
job to meet the requalification requirements of 10 CFR 55. (Seefinding F.)
f.
Reports of operating experience at other plants werescreened by technical analysts who did not have nuclear backgrounds.
They were given no instruction in how to screen such operating
reports, according to Station Manager Gary Miller. The technicalanalysts routed experience summaries to designated people at TMI.
The routing sometimes took several months. The person in the
training department who was assigned to review these summaries often
did not get to them for several months after he received thembecause of the press of other work. The training department held
only one 2-hour class per year on operating experience at otherplants.
47

COMMISSION FINDINGSg.
There was no group with special responsibility forreceiving and acting upon potential safety concerns raised by
employees.
Management did not assure adequate identification ofh.
piping and valves throughout the plant. The Commission staff notedthat pipe and valve identification practices were significantly
Eight hours into the accident,
below standard industrial practices.
Met Ed personnel spent 10 minutes trying unsuccessfully to locate
three decay heat valves in a high radiation field in the auxiliarybuilding.
Management did not assure that Licensee Event Reportsi.
(LER) met basic NRC requirements. A review of TMI-2's LERs
disclosed repeated omissions, inadequate failure analyses, andinadequate corrective actions.
j.
Met Ed did not correct deficiencies in radiation
monitoring equipment, although the deficiencies were pointed out by
an NRC audit months before the accident.
On November 3, 1978, a mechanic caused a completek.
shutdown of the plant, including exercising of emergency systems,
when he tripped a switch on the polisher electrical panel, thinking
he was turning on a light. The only corrective action was to put aguard on the switch.
Sensitive areas of the plant were accessible to large
1.
numbers of people. On the day before the accident, as many as
750 people had access to the auxiliary building.
m.
The manual control station of the polisher bypass
valve was nearly inaccessible and took great effort, in a physicallyawkward position, to operate.
Iodine filters were left in continuous use rathern.
than being preserved to filter air in the event of radioactive
As a result, they did not have full capacity on thecontamination.
day of the accident. (See finding A.11.).

48

COMMISSION FINDINGSF.

TRAINING OF OPERATING PERSONNEL

1.
Training of Met Ed operators and supervisors wasinadequate and contributed significantly to the seriousness of theaccident. The training program gave insufficient emphasis toprinciples of reactor safety.
2.
The TMI training program conformed to the NRC standard fortraining. Moreover, TMI operator license candidates had higherscores than the national average on NRC licensing examinations andoperating tests.
Nevertheless, the training of the operators proved
to be inadequate for responding to the accident.
NRC standards allowed a shallow level of operator
3.
training.
a.
The Operator Licensing Branch activities wereprincipally restricted to preparing and giving initial licensing
examinations and occasional visits to vendors for an informal spot
check of start-up certification tests. The branch was heavily
involved in the initial start-up of the B&W cold licensing programin the early 1970s. A paper review of B&W's course for new plant
operator training was performed without comment in 1976.
b.
NRC prescribed only minimal requirements for operator
training. There were no minimum educational requirements for
operators; there was no requirement for checks to be made on thepsychological fitness of candidates or whether they had criminal
records.
c.
An individual could fail parts of either the NRC
licensing examination or the utility requalification examination,
including sections on emergency procedures and equipment, and still
pass the overall examination by getting a passing average score, andqualify to operate the reactor.
d.
The NRC had no criteria for the qualifications of
those individuals who carry out the operator training program. It
also did not conduct regular in-depth reviews of the training
programs.
49

COMMISSION FINDINGS
4.
Met Ed had primary responsibility for the training of
The quality of the training program at TMI was low.
operators.
The training program was quantitatively and qualitaa.
tively understaffed as well as conceptually weak; emphasis was not
given to fundamental understanding of the reactor and little time
was devoted to instruction in the biological hazards of radiation.
The content was left to the instructors, who had no greater formal
educational qualifications than those of their students.
b.
TMI-2's station manager, unit superintendent, andsupervisor of operations were not involved in operator training.
c.
With NRC approval, the unit superintendent and thestation manager at TMI were only required to acquire the experienceand training necessary to be examined for a senior reactor operator
license, but were not required to hold such a license.
d.
Although auxiliary operators performed tasks that
could affect reactor power level or involve the handling ofradioactive material, there was no formally defined training program
for them.
e.
Met Ed did not request waivers from employees withnaval reactor experience to allow examination of their Navy records.
5.
TMI contracted with B&W to carry out a portion of the TMI
B&W performed only those functions specificallyoperator training.
required under the agreement.
a.
There was little interaction in B&W between those who
conducted training and those responsible for nuclear plant design.
Course content and conduct of courses were made up by the B&W
training department, entirely on its own. There were no formal
syllabi or training manuals.
The simulator at B&W was a key tool in the trainingb.
of operators.
Simulator training did not include preparation of the
Indeed, the B&W simulator
operators for multiple-failure accidents.
was not, prior to March 28, programmed to reproduce the conditions
that confronted the operators during the accident. It was unable tosimulate increasing pressurizer level at the same time that reactor
coolant pressure was dropping.

50

COMMISSION FINDINGSG.

THE NUCLEAR REGULATORY COMMISSION

1.
A purpose of the Energy Reorganization Act of 1974 was todivorce the newly created NRC from promotion of nuclear power.
According to one of the present NRC commissioners, "I still think it[ the NRC] is fundamentally geared to trying to nurture a growing
industry." We find that the NRC is so preoccupied with thelicensing of plants that it has not given primary consideration to
overall safety issues.
2.
NRC labels safety problems that apply to a number ofplants as "generic." Once a problem is labeled "generic," thelicensing of an individual plant can be completed without resolving
the problem.
NRC has a history of leaving generic safety problems
unresolved for periods of many years -- for example, the problem ofanticipated transients without scram. In 1976 during the TMI-2
operating license (OL) review, the Advisory Committee on Reactor
Safeguards recommended, as they did in at least one other OL review,that prior to commercial operation further evaluations be done ofvarious possible accidents, including low-probability accidents.
NRC staff designated this as a "generic issue." TMI-2 received its
OL 2 years later without the resolution of the issue.
3.
Although NRC accumulates an enormous amount of informationon the operating experience of plants, there was no systematic
method of evaluating these experiences and looking for danger
signals of possible generic safety problems. In 1978, the General
Accounting Office criticized NRC for this failure, but no corrective
action had been taken as of the TMI-2 accident.
4.
The NRC commissioners have largely isolated themselvesfrom the licensing process.
Although the commissioners have adopted
unnecessarily stringent ex parte rules to preserve theiradjudicative impartiality, they have also delegated most of theiradjudicative duties to the Atomic Safety and Licensing Appeal Boardand actually adjudicate approximately 25 percent of all licensing
decisions.
That figure is misleadingly high, in part because anumber of the decisions do not represent significant adjudicatory
events and include decisions on exports. The commissioners havealso isolated themselves from the overall management of the NRC.

51

COMMISSION FINDINGSOne of the present NRC commissioners, testifying before Congress,
said, "There has, I think, been too little Commission involvement in
the setting of safety policy in this agency and too little
Commission guidance on safety matters to the staff and to theboard."The major offices within the NRC operate independently
5.
with little evidence of exchange of information or experience. For
example, the fact that operators could be confused due to relianceon pressurizer level had been raised at various levels within the
NRC organization. Yet, the matter "fell between the cracks" andnever worked its way out of the system prior to the TMI-2 accident.
6. Licensing of a nuclear plant is a two-step process. First,
the company must obtain a construction permit (CP) and several years
later must obtain an operating license (OL). The CP stage does not
require complete design plans, and therefore the full safety review
does not occur until the OL stage. By then, hundreds of millions ofdollars have been spent or committed in the construction process.
Therefore, the ultimate safety review may be influenced by economic
considerations that can lead to a reluctance to order major changes
at the OL stage.
7.
The Advisory Committee on Reactor Safeguards (ACRS)
reviews all applications for licenses and poses whatever questions
The ACRS is the only body independent of theit deems appropriate.
NRC staff which regularly reviews safety questions. However, it hasestablished no firm guidelines or procedures, and generally has only
ACRS members are part-timemonthly meetings of limited duration.
and have a very small staff, thus they must rely heavily on the NRC
staff for follow-up of their concerns. ACRS members tend toconcentrate on their own particular areas of expertise, thereby
resulting in a fragmented licensing review.
8.
process.

There are serious inadequacies in the NRC licensing

Applicants for licenses are only required to analyzea.
"single-failure" accidents; they are not required to analyze what
happens when two systems or components fail independently of eachother. The accident at TMI-2 was a multiple-failure accident.
b.
NRC's design safety review places primary emphasis on
those items labeled "safety-related." This designation is crucial
since items not labeled "safety-related" need not be reviewed in thelicensing process, are not required to meet NRC design criteria,
need not be testable, do not require redundancy, and are ordinarily
not subject to NRC inspection. There are no precise criteria as towhich components and systems are to be labeled "safety-related;" theutility makes the initial determination subject to NRC approval.
For example, at TMI-2, the PORV was not a "safety-related" item
because it had a block valve behind it. On the other hand, theblock valve was not "safety-related" because it had a PORV in frontof it.
52

COMMISSION FINDINGSc.
NRC's reliance upon artificial categories of"safety-related" items has caused it to miss important safety issues
and has led the nuclear industry to merely comply with NRC
regulations and to equate that compliance with operational safety.
Thus, over-emphasis by the NRC process on specific categories of
items labeled "safety-related" appears to interfere with thedevelopment, throughout the nuclear industry, of a comprehensive
safety consciousness, that is, a dynamic day-to-day process for
operating safely.
d. There is no identifiable office within NRC
responsibile for systems engineering examination of overall plantdesign and performance, including interactions between major
systems.
e.
There is no office within NRC that specificallyexamines the interface between machines and human beings. Thereseems to be a persistent assumption that plant safety is assured byengineered equipment, and a concommitant neglect of the human beings
who could defeat it if they do not have adequate training, operatingprocedures, information about plant conditions, and manageable
monitors and controls.
For example, despite recognition within NRC
and various industrial groups that outdated technology in thecontrol room could seriously handicap operators during an accident,
NRC continues to license new plants with similarly deficient control
rooms. As noted before, problems with the control room contributed
to the confusion during the TMI accident. (See also finding A.8.)f.
The requirement of additional instrumentation to aid
in accident diagnosis and control was considered by NRC as early as
1975, but its implementation was delayed by industry opposition as
expressed by the Atomic Industrial Forum (AIF). AIF opposition was
based on, among other things, the belief that the instrumentation
required would cover "Class 9" accidents, and therefore, would
extend beyond design-basis requirements.
The lack of
instrumentation to display in the control room the full range oftemperatures from the core thermocouples contributed to theconfusion involved in the attempt to rapidly depressurize theprimary system on March 28.
g.
It is common to issue operating licenses to plants
when there are still "open safety items." When a plant is licensed
with many open items, the Division of Operating Reactors, which has
the technical expertise to supervise operating plants, may refuse toaccept jurisdiction from the Division of Project Management. In
effect, the plant then ends up in a regulatory "limbo," receiving
insufficient attention from either division.
TMI-2 was in this"limbo" at the time of the accident, 13 months after its OL had been
issued.
h.
When NRC issues new guidelines concerning safety,
there is usually no systematic review, on a plant-by-plant basis, ofoperating plants and plants under construction for possible"backfitting." For example, Chairman Hendrie explained to a
Congressional committee that stricter requirements for on- and53

COMMISSION FINDINGS
off-site emergency plans had not been imposed on any alreadyoperating plants because of the need to balance costs against
The committee, however, found no significant cost burden insafety.
requiring utilities to upgrade and implement emergency plans.
Similarly, NRC determined not to backfit the 1975 Standard Review
Plan (SRP) to those plants, such as TMI-2, that received
construction permits prior to September 1, 1975. According to Roger
Mattson, director of the Division of Systems Safety, if individual
SRP requirements had been reviewed for possible backfitting, the SRP
requirement of diverse containment isolation actuation would
probably have been backfitted to plants such as TMI-2. Instead,
TMI-2 containment was isolated only when the pressure in thebuilding exceeded 4 pounds per square inch. Thus, containment
isolation did not occur until several hours after the start of theaccident.
However, this delay had little effect on the actual small
releases of radioactive material during the accident.
Although decisions of significant public healthi.
impact are considered in the licensing process, NRC has no specificmechanism for interactions with public health agencies in thelicensing process, other than the U.S. Environmental Protection
Agency (EPA) which does review Environmental Impact Statements filed
by applicants for CPs and OLs.
9.
The Office of Inspection and Enforcement (I&E) is charged
with determining whether licensees are complying with NRC
regulations, rules, and licensing conditions. Some serious
deficiences in this office are:a.
A 1978 General Accounting Office report found thatI&E inspectors did little independent testing of construction work,
relied heavily on the utility's self-evaluation, spent little timeobserving ongoing construction work, and did not communicate
routinely with people who did the actual construction work. Similar
problems exist in I&E inspections of operating plants. For example,
the principal I&E inspector for TMI-2 completed an inspection
shortly before the accident by examining utility records andinterviewing plant personnel, but without physically examining any
equipment.
b.
A 1978 survey of I&E commissioned by the NRC
determined that the majority of inspectors felt their procedures
were unclear and lacking in sufficient technical guidance.
Of crucial significance to I&E's system of inspectionc.
and enforcement are the Licensee Event Reports (LER) in which utilities report and evaluate important incidents. However, bothlicensees and vendors often have a strong financial disincentive toevaluate and report safety problems that may result in more
stringent regulations, at least in part because it is uncertain
which entity will ultimately bear the cost of increased safety. I&E
makes little effort to systematically review the LERs, has no formal
review mechanism for them, and hence, must rely on individuals toremember events and to identify generic concerns.
54

COMMISSION FINDINGSd.
I&E inspectors at various times have had difficulties
having safety issues that they have raised seriously consideredwithin the office. For example, in 1978 one I&E inspector raised
the issue of operator termination of HPI during the September 1977
For some 5 months, none of his efforts
incident at Davis-Besse.
He then took advantage of the "open-door
produced any action.
policy" of NRC and went directly to two of the commissioners. These
commissioners considered his complaint serious enough to merit
Unfortunately, this meeting with thefurther exploration.
commissioners did not take place until one week before the TMI-2
accident.
Early this year, the General Accounting Office cone.
cluded that NRC had not made effective use of its authority to
The reportassess monetary penalties for significant violations.
cited cases where I&E consolidated continuing violations into one
violation, took too long to impose penalties, and sometimes reduced
the penalties to avoid financial hardship for the licensee.
f.
In its investigative report on the TMI-2 accident(NUREG 0600), I&E came to the unequivocal conclusion that if theoperators had followed their procedures for loss-of-coolant
accidents, there would have been no accident. However, for morethan 2 hours on March 28, the operators at TMI did not recognizethat they had a loss-of-coolant accident and did not consider the
LOCA procedure relevant. In any event, the TMI-2 procedures wereinconsistent and misleading in this regard.
10. There is an absence throughout the NRC of any overallsystem to measure and improve the quality of safety regulations.
There are inadequate management and internal quality assurance
systems, an inadequate research program, and the absence of any
systematic effort to obtain and use the public health-related
research of such federal agencies as HEW and EPA.
The information and direction issued by NRC to licensees
11.
based on operating experience was, at times, fragmented andmisleading.
For example:
An NRC publication describing the September 1977a.
Davis-Besse incident made no mention of the fact that operators
The incident appeared under the heading of "valve
interrupted HPI.
malfunction" not "operator error."b.
In the weeks following the accident, NRC apparently
was confused as to what emergency procedures plant operators shouldThus, within a short span of time, NRC issued and thenfollow.
either modified or contradicted its post-TMI emergency instructions.
Immediately after the TMI accident, NRC(i)directed operators not to override automaticengineered safety features under any circumstances
and to operate high pressure injection without
regard for reactor vessel pressure/temperature

55

COMMISSION FINDINGS
limits.
NRC modified this directive within ashort time.
(ii) On April 5, NRC required all licensees
operating B&W-designed reactors to revise theirprocedures so that in the event of HPI initiation
with reactor coolant pumps (RCP) operating, atleast two RCPs would remain operating. On
July 26, NRC took the opposite position anddirected licensees to shut down its pumps when HPI
initiated.
I&E, in its August 1979 report on the
TMI accident, stated that the failure of the TMI
operators to shut down the RCPs sooner than they
did was a potential item of noncompliance.
12. With its present organization, staff, and attitudes, the
NRC is unable to fullfill its responsibility for providing an
acceptable level of safety for nuclear power plants.

56

COMMISSION FINDINGSH.

THE PUBLIC'S RIGHT TO PUBLIC INFORMATIONThe quality of information provided to the public in the1.
event of a nuclear plant accident has a significant bearing on thecapacity of people to respond to the accident, on their mental
health, and on their willingness to accept guidance from responsible
public officials.
Before the accident, Met Ed had consistently asserted the2.
overall safety of the plant, although the company had madeinformation concerning difficulties at TMI-2 public in weekly press
releases. This information was not pursued, and often notunderstood, by the local news media in the area; and the local news
media generally failed to publish or broadcast investigative stories
on the safety of the plant.
Neither Met Ed nor the NRC had specific plans for3.
providing accident information to the public and the news media.
During the accident, official sources of information were4.
often confused or ignorant of the facts. News media coverage often
reflected this confusion and ignorance.
Met Ed's handling of information during the first 3 days
5.
of the accident resulted in loss of its credibility as an
information source with state and local officials, as well as with
the news media. Part of the problem was that the utility was slow
to confirm "pessimistic" news about the accident.
6.
In accordance with an informal agreement worked out
between Governor Thornburgh and the White House, the release of
information was centralized beginning on the third day of theaccident. Under the agreement, Harold Denton of the NRC would issue
all statements from the site on plant status; the Governor's officewould be the sole source of comment on protective action andevacuation; and the White House would coordinate comment on theThis agreement limited the number
federal emergency relief effort.
of sources available to the news media and while it brought some57

COMMISSION FINDINGS
order out of the chaos in public information, it raised two
problems. First, information on off-site radiation releases was notcentralized in any source so that it would be readily available tothe news media and the public; and second, the plan provided no
specific public information role for the utility.
During the first days of the accident, B&W made a7.
conscious decision not to comment on the accident, even when company
officials believed that misinformation was being made available tothe public by others.
8.
The reporters who covered the accident had widely
Many had no scientificdivergent skills and backgrounds.
background. Because too few technical briefers were supplied by NRC
and the utility, and because many reporters were unfamiliar with thetechnology and the limits of scientific knowledge, they had
difficulty understanding fully the information that was given tothem.
In turn, the news media had difficulty presenting thisinformation to the public in a form that would be understandablea.
This difficulty was particularly acute in thereporting of information on radiation releases.
b.
They also experienced difficulty interpreting
language expressing the probability of such events as a meltdown ora hydrogen explosion; this was made even more difficult when thesources of information were themselves uncertain about theprobabilities.
9.
The impression exists that in news coverage of theaccident, the news media presented a more alarming than reassuringview of events.
Without attempting to assess how alarming theinfact
have been, an analysis of the sources quoted in
accident may
the news media reveals, overall, a larger proportion of reassuring
than alarming statements in the coverage concerning the status of
In choosing quotations from both official andthe accident.
unofficial sources, the news media did not present only "alarming"
views, but rather views on both sides of issues related to theaccident.
10.
A qualitative survey of 42 newspapers from around thecountry showed that the vast majority covered the accident in muchthe same way as the major suppliers of news, such as the wire
services, the broadcast networks, The New York Times, and The
A few newspapers, however, did present a more
Washington Post.
frightening and misleading impression of the accident. This
impression was created through headlines and graphics, and in theselection of material to print.

58

A.

The Nuclear Regulatory Commission

B.

The Utility and Its SuppliersC.

Training of Operating Personnel

D.

Technical Assessment

E.

Worker and Public Health and Safety

F.

Emergency Planning and Response

G.

The Public's Right to Information

60

COMMISSION
RECOMMENDATIONSA.

THE NUCLEAR REGULATORY COMMISSION

The Commission found a number of inadequacies in the NRC and,
therefore, proposes a restructuring of the agency. Because there isinsufficient direction in the present statute, the President andCongress should consider incorporating many of the following measures instatutory form.
Agency Organization and Management
The Commission believes that as presently constituted, the NRC does
not possess the organizational and management capabilities necessary forthe effective pursuit of safety goals. The Commission recommends:
The Nuclear Regulatory Commission should be restructured as a1.
new independent agency in the executive branch.
a.

The present five-member commission should be abolished.

The new agency should be headed by a single administratorb.
appointed by the President, subject to the advice and consent of the
Senate, to serve a substantial term (not coterminous with that of the
President) in order to provide an expectation of continuity, but at thepleasure of the President to allow removal when the President deems it
The administrator should be a person from outside thenecessary.
present agency.
c.
The administrator should have substantial discretionary
authority over the internal organization and management of the newagency, and over personnel transfers from the existing NRC. Unlike thepresent NRC arrangement, the administrator and major staff components
should be located in the same building or group of buildings.
A major role of the administrator should be assuring thatd.
offices within the agency communicate sufficiently so that research,
operating experience, and inspection and enforcement affect the overall
performance of the agency.
61

COMMISSION RECOMMENDATIONS
2.
An oversight committee on nuclear reactor safety should be
Its purpose would be to examine, on a continuing basis,
established.
the performance of the agency and of the nuclear industry in addressing
and resolving important public safety issues associated with theconstruction and operation of nuclear power plants, and in exploring theoverall risks of nuclear power.
The members of the committee, not to exceed 15 in number,a.
should be appointed by the President and should include: persons
conversant with public health, environmental protection, emergency
planning, energy technology and policy, nuclear power generation, andnuclear safety; one or more state governors; and members of the generalpublic.
The committee, assisted by its own staff, should reportb.
to the President and to Congress at least annually.
The Advisory Committee on Reactor Safeguards (ACRS) should be3.
retained, in a strengthened role, to continue providing an independent
technical check on safety matters. The members of the committee should
continue to be part-time appointees; the Commission believes that theindependence and high quality of the members might be compromised bymaking them full-time federal employees.
The Commission recommends thefollowing changes:
The staff of ACRS should be strengthened to providea.
increased capacity for independent analysis. Special consideration
should be given to improving ACRS' capabilities in the field of publichealth.
The ACRS should not be required to review each licenseb.
When
ACRS chooses to review a license application, it
application.
should have the statutory right to intervene in hearings as a party. In
particular, ACRS should be authorized to raise any safety issue inlicensing proceedings, to give reasons and arguments for its views, andto require formal response by the agency to any submission it makes.
Any member of ACRS should be authorized to appear and testify inhearings, but should be exempt from subpoena in any proceedings in which
he has not previously appeared voluntarily or made an individual written
submission.
c.
ACRS should have similar rights in rulemaking
In particular, it should have the power to initiate aproceedings.
rulemaking proceeding before the agency to resolve any generic safetyissue it identifies.
The Agency's Substantive Mandate
The new agency's primary statutory mission and first operating
priority must be the assurance of safety in the generation of.nuclear
power, including safeguards of nuclear materials from theft, diversion,or loss.
Accordingly, the Commission recommends the following:

62

COMMISSION RECOMMENDATIONS
4.
Included in the agency's general substantive charge should be
the requirement to establish and explain safety-cost trade-offs; where
additional safety improvements are not clearly outweighed by costconsiderations, there should be a presumption in favor of the safetychange.
Transfers of statutory jurisdiction from the NRC should be
preceded by a review to identify and remove any unnecessary
responsibilities that are not germane to safety. There should also beemphasis on the relationship of the new agency's safety activities torelated activities of other agencies. (See recommendations E.2 andF.1.b.)a.
The agency should be directed to upgrade its operator andsupervisor licensing functions.
These should include the accreditationof training institutions from which candidates for a license must
graduate.
Such institutions should be required to employ qualified
instructors, to perform emergency and simulator training, and to include
instruction in basic principles of reactor science, reactor safety, andthe hazards of radiation. The agency should also set criteria for
operator qualifications and background investigations, and strictly test
license candidates for the particular power plant they will operate.
The agency should periodically review and reaccredit all training
programs and relicense individuals on the basis of current information
on experience in reactor operations. (See recommendations C.1 and C.2.)b.
The agency should be directed to employ a broader
definition of matters relating to safety that considers thoroughly thefull range of safety matters, including, but not limited to, those now
identified as "safety-related" items, which currently receive special
attention.
c.

Other safety emphases should include:(i) a systems engineering examination of overall plantdesign and performance, including interaction among major
systems and increased attention to the possibility ofmultiple failures;(ii) review and approval of control room design; theagency should consider the need for additional
instrumentation and for changes in overall design to aid
understanding of plant status, particularly for responseto emergencies; (see recommendation D.1) and(iii) an increased safety research capacity with abroadly defined scope that includes issues relevant topublic health.
It is particularly necessary tocoordinate research with the regulatory process in aneffort to assure the maximum application of scientificknowledge in the nuclear power industry.

5.
Responsibility and accountability for safe power plant
operations, including the management of a plant during an accident,

63

COMMISSION RECOMMENDATIONS
should be placed on the licensee in all circumstances. It is therefore
necessary to assure that licensees are competent to discharge this
responsibility.
To assure this competency, and in light of ourfindings regarding Metropolitan Edison, we recommend that the agency
establish and enforce higher organizational and management standards forlicensees. Particular attention should be given to such matters as theintegration of decision-making in any organization licensed
following:
to construct or operate a plant; kinds of expertise that must be within
the organization; financial capability; quality assurance programs;
operator and supervisor practices and their periodic reevaluation; plantsurveillance and maintenance practices; and requirements for the
analysis and reporting of unusual events.
6.
In order to provide an added contribution to safety, theagency should be required, to the maximum extent feasible, to locate new
power plants in areas remote from concentrations of population. Siting
determinations should be based on technical assessments of various
classes of accidents that can take place, including those involving
releases of low doses of radiation. (See recommendation F.2.)
The agency should be directed to include, as part of its
7.
licensing requirements, plans for the mitigation of the consequences ofaccidents, including the cleanup and recovery of the contaminated plant.
The agency should be directed to review existing licenses and to set
deadlines for accomplishing any necessary modifications. (Seerecommendations D.2 and D.4.)
8.
Because safety measures to afford better protection for theaffected population can be drawn from the high standards for plantsafety recommended in this report, the NRC or its successor should, on acase-by-case basis, before issuing a new construction permit oroperating license:
assess the need to introduce new safety improvementsa.
recommended in this report, and in NRC and industry studies;b.
review, considering the recommendations set forth in thisreport, the competency of the prospective operating licensee to manage
the plant and the adequacy of its training program for operating
personnel; andcondition licensing upon review and approval of the statec.
and local emergency plans.
Agency Procedures
The Commission believes that the agency must improve on priorperformance in resolving generic and specific safety issues. Genericsafety issues are considered in rulemaking proceedings that formulate
new standards for categories of plants. Specific safety issues are
considered in adjudicative proceedings that determine whether aparticular plant should receive a license. Both kinds of safety issues

64

COMMISSION RECOMMENDATIONS
are then dealt with in inspection and enforcement processes. The
Commission believes that all of these agency functions need improvement,
and accordingly recommends the following measures:
9.
The agency's authorization to make general rules affecting
safety should:a.
require the development of a public agenda according towhich rules will be formulated;b.
require the agency to set deadlines for resolving genericsafety issues;c.
require a periodic and systematic reevaluation of theagency's existing rules; andd.
define rulemaking procedures designed to create a processthat provides a meaningful opportunity for participation by interested
persons, that ensures careful consideration and explanation of rules
adopted by the agency, and that includes appropriate provision for theapplication of new rules to existing plants. In particular, the agency
should:accompany newly proposed rules with an analysis of the issues
they raise and provide an indication of the technical materials that are
relevant; provide a sufficient opportunity for interested persons toevaluate and rebut materials relied on by the agency or submitted byothers; explain its final rules fully, including responses to principal
comments by the public, the ACRS, and other agencies on proposed rules;
impose when necessary special interim safeguards for operating plants
affected by generic safety rulemaking; and conduct systematic reviews ofoperating plants to assess the need for retroactive application of newsafety requirements.
10. Licensing procedures should foster early and meaningful
resolution of safety issues before major financial commitments inconstruction can occur. In order to ensure that safety receives primaryemphasis in licensing, and to eliminate repetitive consideration of someissues in that process, the Commission recommends the following:a.
Duplicative consideration of issues in several stages of
one plant's licensing should, wherever possible, be reduced byallocating particular issues (such as the need for power) to a single
stage of the proceedings.
b.
by rulemaking.

Issues that recur in many licensings should be resolvedc.
The agency should be authorized to conduct a combined
construction permit and operating license hearing whenever plans can bemade sufficiently complete at the construction permit stage.
d.
There should be provision for the initial adjudication oflicense applications and for appeal to a board whose decisions would not

65

COMMISSION RECOMMENDATIONS
be subject to further appeal to the administrator. Both initial
adjudicators and appeal boards should have a clear mandate to pursue any
safety issue, whether or not it is raised by a party.
e.
An Office of Hearing Counsel should be established in theagency.
This office would not engage in the informal negotiations
between other staff and applicants that typically precede formal
hearings on construction permits. instead, it would participate in theformal hearings as an objective party, seeking to assure that vital
safety issues are addressed and resolved. The office should report
directly to the administrator and should be empowered to appeal any
adverse licensing board determination to the appeal board.
Any specific safety issue left open in licensing
f.
proceedings should be resolved by a deadline.
11. The agency's inspection and enforcement functions must receive
increased emphasis and improved management, including the following
elements:a.
There should be an improved program for the systematic
safety evaluation of currently operating plants, in order to assess
compliance with current requirements, to assess the need to make newrequirements retroactive to older plants, and to identify new safetyissues.
b.
There should be a program for the systematic assessmentof experience in operating reactors, with special emphasis on
An overall quality
discovering patterns in abnormal occurrences.
assurance measurement and reporting system based on this systematic
assessment shall be developed to provide: 1) a measure of the overall
improvement or decline in safety, and 2) a base for specific programs
aimed at curing deficiencies and improving safety. Licensees mustreceive clear instructions on reporting requirements and clear
communications summarizing the lessons of experience at other reactors.
c.
The agency should be authorized and directed to assess
substantial penalties for licensee failure to report new"safety-related" information or for violations of rules defining
practices or conditions already known to be unsafe.
d.
The agency should be directed to require its enforcement
personnel to perform improved inspection and auditing of licensee compliance with regulations and to conduct major and unannounced on-site
inspections of particular plants.
e.
Each operating licensee should be subject periodically tointensive and open review of its performance according to therequirements of its license and applicable regulations.

66

COMMISSION RECOMMENDATIONSf.
The agency should be directed to adopt criteria forrevocation of licenses, sanctions short of revocation such asprobationary status, and kinds of safety violations requiring immediate
plant shutdown or other operational safeguards.

67

COMMISSION RECOMMENDATIONSB.

THE UTILITY AND ITS SUPPLIERS

1.
To the extent that the industrial institutions we haveexamined are representative of the nuclear industry, the nuclear
industry must dramatically change its attitudes toward safety andregulations.
The Commission has recommended that the new regulatory
agency prescribe strict standards.
At the same time, the Commission
recognizes that merely meeting the requirements of a government
regulation does not guarantee safety.
Therefore, the industry must also
set and police its own standards of excellence to ensure the effective
management and safe operation of nuclear power plants.
a.
The industry should establish a program that specifies
appropriate safety standards including those for management, quality
assurance, and operating procedures and practices, and that conducts
independent evaluations. The recently created Institute of Nuclear
Power Operations, or some similar organization, may be an appropriate
vehicle for establishing and implementing this program.
b.
There must be a systematic gathering, review, andanalysis of operating experience at all nuclear power plants coupledwith an industry-wide international communications network to facilitate
the speedy flow of this information to affected parties. If such
experiences indicate the need for modifications in design or operation,such changes should be implemented according to realistic deadlines.
2.
Although the Commission considers the responsibility forsafety to be with the total organization of the plant, we recommend thateach nuclear power plant company have a separate safety group thatreports to high-level management.
Its assignment would be to evaluate
regularly procedures and general plant operations from a safety
perspective; to assess quality assurance programs; and to develop
continuing safety programs.
3.
Integration of management responsibility at all levels must be
achieved consistently throughout this industry.
Although there may not
be a single optimal management structure for nuclear power plant
operation, there must be a single accountable organization with therequisite expertise to take responsibility for the integrated management

68

COMMISSION RECOMMENDATIONS
of the design, construction, operation, and emergency response
functions, and the organizational entities that carry them out. Without
such demonstrated competence, a power plant operating company should not
qualify to receive an operating license.
a.
These goals may be obtained at the design stage by1) contracting for a "turn-key" plant in which the vendor orarchitect-engineer contracts to supply a fully operational plant andsupervises all planning, construction, and modification; or 2) assembling
expertise capable of integrating the design process. In either case, it
is critical that the knowledge and expertise gained during design andconstruction of the plant be effectively transferred to those
responsible for operating the plant.
b.
Clearly defined roles and responsibilities for operatingprocedures and practices must be established to ensure accountability
and smooth communication.
c.
Since, under our recommendations, accountability for
operations during an emergency would rest on the licensee, the licensee
must prepare clear procedures defining management roles and responsibilities in the event of a crisis.
4.
It is important to attract highly qualified candidates for the
positions of senior operator and operator supervisor. Pay scales should
be high enough to attract such candidates.
5.
Substantially more attention and care must be devoted to thewriting, reviewing, and monitoring of plant procedures.
a.

The wording of procedures must be clear and concise.

b.
The content of procedures must reflect both engineering
thinking and operating practicalities.
c.
The format of procedures, particularly those that deal
with abnormal conditions and emergencies, must be especially clear,
including clear diagnostic instructions for identifying the particularabnormal conditions confronting the operators.
d.
Management of both utilities and suppliers must insist on
the early diagnosis and resolution of safety questions that arise inplant operations.
They must also establish deadlines, impose sanctions
for the failure to observe such deadlines, and make certain that theresults of the diagnoses and any proposed procedural changes based onthem are disseminated to those who need to know them.
6.
Utility rate-making agencies should recognize that
implementation of new safety measures can be inhibited by delay or
failure to include the costs of such measures in the utility rate base.
The Commission, therefore, recommends that state rate-making agencies
give explicit attention to the safety implications of rate-making when
they consider costs based on "safety-related" changes.
69

COMMISSION RECOMMENDATIONSC.

TRAINING OF OPERATING PERSONNEL

1.
The Commission recommends the establishment ofagency-accredited training institutions for operators and immediate
These institutions should have highly
supervisors of operators.
qualified instructors, who will maintain high standards, stressunderstanding of the fundamentals of nuclear power plants and thepossible health effects of nuclear power, and who will train operators
to respond to emergencies. (See recommendation A.4.a.)a.
These institutions could be national, regional, or
specific to individual nuclear steam systems.
b.
Reactor operators should be required to graduate from an
Exemption should be made only in cases
accredited training institution.
where there is clear, documentary evidence that the candidate alreadyhas the equivalent training.
The training institutions should be subject to periodicc.
review and reaccreditation by the restructured NRC.
Candidates for the training institute must meet entranced.
requirements geared to the curriculum.
2.
Individual utilities should be responsible for training
operators who are graduates of accredited institutions in the specifics
of operating a particular plant. These operators should be examined andlicensed by the restructured NRC, both at their initial licensing and at
the relicensing stage. In order to be licensed, operators must pass
every portion of the examination. Supervisors of operators, at aminimum, should have the same training as operators.
Training should not end when operators are given their3.
licenses.
Comprehensive ongoing training must be given on a regulara.
basis to maintain operators' level of knowledge.
Such training must be continuously integrated withb.
operating experience.
70

COMMISSION RECOMMENDATIONSEmphasis must be placed on diagnosing and controllingc.
complex transients and on the fundamental understanding of reactor
safety.
Each utility should have ready access to a control roomd.
simulator. Operators and supervisors should be required to train
The holding of operator licenses should be
regularly on the simulator.
contingent on performance on the simulator.
4.
Research and development should be carried out on improving
simulation and simulation systems: a) to establish and sustain a higher
level of realism in the training of operators, including dealing withtransients; and b) to improve the diagnostics and general knowledge of
nuclear power plant systems.

71

COMMISSION RECOMMENDATIONSD.

TECHNICAL ASSESSMENT

1.
Equipment should be reviewed from the point of view ofproviding information to operators to help them prevent accidents and tocope with accidents when they occur. Included might be instruments thatcan provide proper warning and diagnostic information; for example, themeasurement of the full range of temperatures within the reactor vessel
under normal and abnormal conditions, and indication of the actual
position of valves. Computer technology should be used for the clear
display for operators and shift supervisors of key measurements relevant
to accident conditions, together with diagnostic warnings of conditions.
In the interim, consideration should be given to requiring, at TMI
and similar plants, the grouping of these key measurements, including
distinct warning signals on a single panel available to a specified
operator and the providing of a duplicate panel of these key
measurements and warnings in the shift supervisor's office.
Equipment design and maintenance inadequacies noted at TMI
2.
should be reviewed from the point of view of mitigating the consequences
Inadequacies noted in the following should be corrected:of accidents.
iodine filters, the hydrogen recombiner, the vent gas system,
containment isolation, reading of water levels in the containment
isolation, reading of water levels in the containment area, radiation
monitoring in the containment building, and the capability to take andquickly analyze samples of containment atmosphere and water in various
places.
(See recommendation A.7.)
Monitoring instruments and recording equipment should be
3.
provided to record continuously all critical plant measurements andconditions.
The Commission recommends that continuing in-depth studies
4.
should be initiated on the probabilities and consequences (on-site andoff-site) of nuclear power plant accidents, including the consequencesof meltdown.
These studies should include a variety of small-breaka.
loss-of-coolant accidents and multiple-failure accidents, withparticular attention to human failures.
72

COMMISSION RECOMMENDATIONSResults of these studies should be used to help plan forb.
recovery and cleanup following a major accident.
c.
From these studies may emerge desirable modifications in
the design of plants that will help prevent accidents and mitigate their
For example:
consequences.
(i) Consideration should be given to equipment thatwould facilitate the controlled safe venting of hydrogengas from the reactor cooling system.
(ii) Consideration should be given to overall gas-tightenclosure of the let-down/make-up system with the optionof returning gases to the containment building.
d.
Such studies should be conducted by the industry andother qualified organizations and may be sponsored by the restructured
NRC and other federal agencies.
A study should be made of the chemical behavior and the5.
extensive retention of radioactive iodine in water, which resulted in
the very low release of radioiodine to the atmosphere in the TMI-2
accident. This information should be taken into account in the studiesof the consequences of other small-break accidents.
Since there are still health hazards associated with the6.
cleanup and disposal process, which is being carried out for the firsttime in a commercial nuclear power plant, the Commission recommends
close monitoring of the cleanup process at TMI and of the transportationand disposal of the large amount of radioactive material. As much dataas possible should be preserved and recorded about the conditions within
the containment building so that these may be used for future safety
analyses.
The Commission recommends that as a part of the formal safety7.
assurance program, every accident or every new abnormal event be
carefully screened, and where appropriate be rigorously investigated, toassess its implications for the existing system design, computer modelsof the system, equipment design and quality, operations, operator
training, operator training simulators, plant procedures, safetysystems, emergency measures, management, and regulatory requirements.

73

COMMISSION RECOMMENDATIONSE.

WORKER AND PUBLIC HEALTH AND SAFETY

The Commission recommends the establishment of expanded and1.
This
better coordinated health-related radiation effects research.
research should include, but not be limited to:a.

biological effects of low levels of ionizing radiation;

acceptable levels of exposure to ionizing radiation forb.
the general population and for workers;c.
development of methods of monitoring and surveillance,
including epidemiologic surveillance to monitor and determine theconsequences of exposure to radiation of various population groups,
including workers;d.
development of approaches to mitigate adverse healtheffects of exposure to ionizing radiation; ande.
genetic or environmental factors that predispose
individuals to increased susceptibility to adverse effects.
This effort should be coordinated under the National Institutes of
Health -- with an interagency committee of relevant federal agencies toestablish the agenda for research efforts -- including the commitment of
a portion of the research budget to meet the specific needs of therestructured NRC.
To ensure the best available review of radiation-related2.
health issues, including reactor siting issues, policy statements or
regulations in that area of the restructured NRC should be subject tomandatory review and comment by the Secretary of the Department of
Health and Human Services. A time limit for the review should beestablished to assure such review is performed in an expeditious manner.
The Commission recommends, as a state and local
3.
responsibility, an increased program for educating health professionals
and emergency response personnel in the vicinity of nuclear power
plants.

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COMMISSION RECOMMENDATIONS
4.
Utilities must make sufficient advance preparation for the
mitigation of emergencies:a.
Radiation monitors should be available for monitoring ofroutine operations as well as accident levels.
b.
The emergency control center for health-physics
operations and the analytical laboratory to be used in emergencies
should be located in a well-shielded area supplied with uncontaminatedair.
c.
There must be a sufficient health-related supply of
instruments, respirators, and other necessary equipment for both routine
and emergency conditions.
d.
There should be an adequate maintenance program for all
such health-related equipment.
5.
An adequate supply of the radiation protective (thyroid
blocking) agent, potassium iodide for human use, should be available
regionally for distribution to the general population and workers
affected by a radiological emergency.

75

COMMISSION RECOMMENDATIONSF.

EMERGENCY PLANNING AND RESPONSE

1.
Emergency plans must detail clearly and consistently theactions public officials and utilities should take in the event ofoff-site radiation doses resulting from release of radioactivity.
Therefore, the Commission recommends that:a.
Before a utility is granted an operating license for a
new nuclear power plant, the state within which that plant is to besited must have an emergency response plan reviewed and approved by theFederal Emergency Management Agency (FEMA).
The agency should assess
the criteria and procedures now used for evaluating state and local
government plans and for determining their ability to activate theplans. FEMA must assure adequate provision, where necessary, formulti-state planning.
b.
The responsibility at the federal level for radiologicalemergency planning, including planning for coping with radiologicalreleases, should rest with FEMA. In this process, FEMA should consult
with other agencies, including the restructured NRC and the appropriate
health and environmental agencies. (See recommendation A.4.)c.
The state must effectively coordinate its planning withthe utility and with local officials in the area where the plant is tobe located.
d.
States with plants already operating must upgrade theirplans to the requirements to be set by FEMA. Strict deadlines must be
established to accomplish this goal.
2.
Plans for protecting the public in the event of off-siteradiation releases should be based on technical assessment of various
classes of accidents that can take place at a given plant.
a.
No single plan based on a fixed set of distances and afixed set of responses can be adequate. Planning should involve theidentification of several different kinds of accidents with different
possible radiation consequences.
For each such scenario, there should
be clearly identified criteria for the appropriate responses at various

76

COMMISSION RECOMMENDATIONS
distances, including instructing individuals to stay indoors for aperiod of time, providing special medication, or ordering an evacuation.
b.
Similarly, response plans should be keyed to various
possible scenarios and activated when the nature and potential hazard ofa given accident has been identified.
c.
Plans should exist for protecting the public at radiationlevels lower than those currently used in NRC-prescribed plans.
d.
All local communities should have funds and technicalsupport adequate for preparing the kinds of plans described above.
3.
Research should be expanded on medical means of protecting the
public against various levels and types of radiation. This researchshould include exploration of appropriate medications that can protect
against or counteract radiation.
4.
If emergency planning and response to a radiation-related
emergency is to be effective, the public must be better informed about
nuclear power.
The Commission recommends a program to educate thepublic on how nuclear power plants operate, on radiation and its healtheffects, and on protective actions against radiation. Those who would
be affected by such emergency planning must have clear information on
actions they would be required to take in an emergency.
5.
Commission studies suggest that decision-makers may haveover-estimated the human costs, in injury and loss of life, in many massevacuation situations.
The Commission recommends study into the humancosts of radiation-related mass evacuation and the extent, if any, towhich the risks in radiation-related evacuations differ from other typesof evacuations.
Such studies should take into account the effects ofimproving emergency planning, public awareness of such planning, andcosts involved in mass evacuations.
6.
Plans for providing federal technical support, such asradiological monitoring, should clearly specify the responsibilities ofthe various support agencies and the procedures by which those agencies
provide assistance.
Existing plans for the provision of federal
assistance, particularly the Interagency Radiological Assistance Plan
and the various memoranda of understanding among the agencies, should be
reexamined and revised by the appropriate federal authorities in thelight of the experience of the TMI accident, to provide for better
coordination and more efficient federal support capability.

77

COMMISSION RECOMMENDATIONSG.

THE PUBLIC'S RIGHT TO INFORMATION

1.
Federal and state agencies, as well as the utility, shouldmake adequate preparation for a systematic public information program sothat in time of a radiation-related emergency, they can provide timely
and accurate information to the news media and the public in a form thatis understandable.
There should be sufficient division of briefing
responsibilities as well as availability of informed sources to reduce
The Commission therefore
confused and inaccurate information.
recommends:a.
Since the utility must be responsible for the managementof the accident, it should also be primarily responsible for providing
information on the status of the plant to the news media and to the
public; but the restructured NRC should also play a supporting role andbe available to provide background information and technical briefings.
b.
Since the state government is responsible for decisions
concerning protective actions, including evacuations, a designated stateagency should be charged with issuing all information on this subject.
This agency is also charged with the development of and dissemination of
accurate and timely information on off-site radiation doses resulting
from releases of radioactivity.
This information should be derived from(See recommendation F.1.)
This agency should also
appropriate sources.
set up the machinery to keep local officials fully informed ofdevelopments and to coordinate briefings to discuss any federal
involvement in evacuation matters.
2.
The provision of accurate and timely information places
special responsibilities on the official sources of this information.
The effort must meet the needs of the news media for information but
without compromising the ability of operational personnel to manage theaccident.
The Commission therefore recommends that:a.
Those who brief the news media must have direct access to
informed sources of information.
b.
Technical liaison people should be designated to informthe briefers and to serve as a resource for the news media.

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COMMISSION RECOMMENDATIONS
The primary official news sources should have plans forc.
the prompt establishment of press centers reasonably close to the site.
These must be properly equipped, have appropriate visual aids andreference materials, and be staffed with individuals who areknowledgeable in dealing with the news media. These press centers must
be operational promptly upon the declaration of a general emergency or
its equivalent.
The coverage of nuclear emergencies places special respons3.
ibilities on the news media to provide accurate and timely information.
The Commission therefore recommends that:a.
All major media outlets (wire services, broadcast
networks, news magazines, and metropolitan daily newspapers) hire andtrain specialists who have more than a passing familiarity with reactors
and the language of radiation. All other news media, regardless of
their size, located near nuclear power plants should attempt to acquire
similar knowledge or make plans to secure it during an emergency.
Reporters discipline themselves to place complexb.
information in a context that is understandable to the public and thatallows members of the public to make decisions regarding their healthand safety.
c.
Reporters educate themselves to understand the pitfalls
in interpreting answers to "what if" questions. Those covering an
accident should have the ability to understand uncertainties expressedby sources of information and probabilities assigned to various possible
dangers.
4.
State emergency plans should include provision for creation of
local broadcast media networks for emergencies that will supply timely
and accurate information.
Arrangements should be made to make available
knowledgeable briefers to go on the air to clear up rumors and explain
conditions at the plant. Communications between state officials, theutility, and the network should be prearranged to handle the possibilityof an evacuation announcement.
5.
The Commission recommends that the public in the vicinity of a
nuclear power plant be routinely informed of local radiation
measurements that depart appreciably from normal background radiation,
whether from normal or abnormal operation of the nuclear power plant,
from a radioactivity cleanup operation such as that at TMI-2, or fromother sources.

79

ACCOUNTOF THE ACCIDENTPROLOGUE

On Wednesday, March 28, 1979, 36 seconds after the hour of 4:00
a.m., several water pumps stopped working in the Unit 2 nuclear
power plant on Three Mile Island, 10 miles southeast of Harrisburg,
Pennsylvania. l / Thus began the accident at Three Mile Island. In
the minutes, hours, and days that followed, a series of events -compounded by equipment failures, inappropriate procedures, andhuman errors and ignorance -- escalated into the worst crisis yet
experienced by the nation's nuclear power industry.
The accident focused national and international attention on
the nuclear facility at Three Mile Island and raised it to a placeof prominence in the minds of hundreds of millions. For the people
living in such communities as Royalton, Goldsboro, Middletown,
Hummelstown, Hershey, and Harrisburg, the rumors, conflicting
official statements, a lack of knowledge about radiation releases,
the continuing possibility of mass evacuation, and the fear that ahydrogen bubble trapped inside a nuclear reactor might explode werereal and immediate. Later, Theodore Gross, provost of the Capitol
Campus of Pennsylvania State University located in Middletown a few
miles from TMI, would tell the Commission:
Never before have people been asked to live with such ambiguity.
The TMI accident -- an accident we cannot see or taste orsmell . . . is an accident that is invisible. I think thefact that it is invisible creates a sense of uncertainty andfright on the part of people that may well go beyond thereality of the accident itself.2/
The reality of the accident, the realization that such an
accident could actually occur, renewed and deepened the national
debate over nuclear safety and the national policy of using nuclear
reactors to generate electricity.
-0-0-0-Three Mile Island is home to two nuclear power plants, TMI-1
Together they have a generating capacity of 1,700 megawatts,
and TMI-2.
Photo at left: Goldsboro, Pennsylvania, March 28, 1979.

81

ACCOUNT OF TILE ACCIDENT

Simulated fuel pellets. The actual pellets are molded uraniumoxide and are stacked one atop another inside the fuel rods. Eachpellet is about one inch tall and less than a half-inch wide.

82

ACCOUNT OF THE ACCIDENT
enough electricity to supply the needs of 300,000 homes. The twoplants are owned jointly by Pennsylvania Electric Company, Jersey
Central Power & Light Company, and Metropolitan Edison Company, andoperated by Met Ed. These three companies are subsidiaries ofGeneral Public Utilities Corporation, an electric utility holding
company headquartered in Parsippany, New Jersey.3/
Each TMI plant is powered by its nuclear reactor. A reactor'sfunction in a commercial power plant is essentially simple -- toheat water.
The hot water, in turn, produces steam, which drives aturbine that turns a generator to produce electricity. Nuclear
reactors are a product of high technology. In recent years, nuclear
facilities of generating capacity much larger than those of earlier
years -- including TMI-1 and TMI-2 -- have gone into service.4/
A nuclear reactor generates heat as a result of nuclear fission,
the splitting apart of an atomic nucleus, most often that of theheavy atom uranium.
Each atom has a central core called a nucleus.
The nuclei of atoms typically contain two types of particles tightly
bound together:
protons, which carry a positive charge, and neutrons,
which have no charge.
When a free neutron strikes the nucleus of auranium atom, the nucleus splits apart. This splitting -- or fission -produces two smaller radioactive atoms, energy, and free neutrons.
Most of the energy is immediately converted to heat. The neutrons
can strike other uranium nuclei, producing a chain reaction andcontinuing the fission process.
Not all free neutrons split atomic
nuclei.
Some, for example, are captured by atomic nuclei. This isimportant, because some elements, such as boron or cadmium, arestrong absorbers of neutrons and are used to control the rate offission, or to shut off a chain reaction almost instantaneously.5/
Uranium fuels all nuclear reactors used commercially to generate
electricity in the United States.
At TMI-2, the reactor core holds
some 100 tons of uranium. The uranium, in the form of uraniumoxide, is molded into cylindrical pellets, each about an inch talland less than half-an-inch wide. The pellets are stacked one atop
another inside fuel rods. These thin tubes, each about 12 feetlong, are made of Zircaloy-4, a zirconium alloy. This alloy shell -called the "cladding" -- transfers heat well and allows most neutrons
to pass through.6/
TMI-2's reactor contained 36,816 fuel rods -- 208 in each ofits 177 fuel assemblies. A fuel assembly contains not only fuelrods, but space for cooling water to flow between the rods and tubes
that may contain control rods or instruments to measure such things
as the temperature inside the core. TMI-2's reactor has 52 tubes
with instruments and 69 with control rods.7/
Control rods contain materials that are called "poisons" by the
nuclear industry because they are strong absorbers of neutrons andshut off chain reactions. The absorbing materials in TMI-2's control
rods are 80 percent silver, 15 percent indium, and 5 percent cadmium.
When the control rods are all inserted in the core, fission iseffectively blocked, as atomic nuclei absorb neutrons so that theycannot split other nuclei.
A chain reaction is initiated by withdrawing
83

ACCOUNT OF THE ACCIDENT
the control rods.
By varying the number of and the length to which
the control rods are withdrawn, operators can control how much powera plant produces. The control rods are held up by magnetic clamps.
In an emergency, the magnetic field is broken and the control rods,
responding to gravity, drop immediately into the core to halt fission.
This is called a "scram."
The nuclear reactors used in commercial power plants possess
They are designed so that it isseveral important safety features.
impossible for them to explode like an atomic bomb. The primarydanger from nuclear power stations is the potential for the releaseof radioactive materials produced in the reactor core as the result
These materials are normally contained within the fuelof fission.
rods.
A fuel rod assembly, containing 208 individual fuel rods, being
inserted into the core of TMI-1.

84

ACCOUNT OF THE ACCIDENT
Damage to the fuel rods can release radioactive material into
the reactor's cooling water and this radioactive material might bereleased to the environment if the other barriers -- the reactor
coolant system and containment building barriers -- are also breached.8/
A nuclear plant has three basic safety barriers, each designed
to prevent the release of radiation. The first line of protectionis the fuel rods themselves, which trap and hold radioactive materials
produced in the uranium fuel pellets. The second barrier consistsof the reactor vessel and the closed reactor coolant system loop.
The TMI-2 reactor vessel, which holds the reactor core and its
control rods, is a 40-foot high steel tank with walls 8-' inches
thick. This tank, in turn, is surrounded by two, separated concreteand-steel shields, with a total thickness of up to 9-/ feet, which
View of TMI-1's core taken from about 50 feet above the core. Eachfuel rod assembly fits into one of the squares in the core's Qrid.
-jW
p

-

W
t

85

ACCOUNT OF THE ACCIDENT
absorb radiation and neutrons emitted from the reactor core.
Finally, all this is set inside the containment building, a 193-foothigh, reinforced-concrete structure with walls 4 feet thick.9/
To supply the steam that runs the turbine, both plants at TMI
rely on a type of steam supply system called a pressurized waterThis simply means that the water heated by the reactor isreactor.
kept under high pressure, normally 2,155 pounds per square inch in
the TMI-2 plant.
In normal operations, it is important in a pressurized water
reactor that the water that is heated in the core remain below"saturation" -- that is, the temperature and pressure combination atwhich water boils and turns to steam. In an accident, steam formation
Schematic of the TMI-2 facility.

86

ACCOUNT OF THE ACCIDENT
itself is not a danger, because it too can help cool the fuel rods,
although not as effectively as the coolant water. But problems canoccur if so much of the core's coolant water boils away that thecore becomes uncovered.

An uncovered core may lead to two problems. First, temperature
may rise to a point, roughly 2,200°F, where a reaction of water andthe cladding could begin to damage the fuel rods and also producehydrogen.
The other is that the temperature might rise above themelting point of the uranium fuel, which is about 5,200°F. Either
poses a potential danger. Damage to the zirconium cladding releases
some radioactive materials trapped inside the fuel rods into thecore's cooling water.
A melting of the fuel itself could releasefar more radioactive materials. If a significant portion of the87

ACCOUNT OF THE ACCIDENT
fuel should melt, the molten fuel could melt through the reactor
vessel itself and release large quantities of radioactive materials
into the containment building. What might happen following such an
event is very complicated and depends on a number of variables suchas the specific characteristics of the materials on which a particular
containment building is constructed.10/
The essential elements of the TMI-2 system during normal operations
include:••The reactor, with its fuel rods and control rods.

Water, which is heated by the fission process going on
inside the fuel rods to ultimately produce steam to run theturbine.
This water, by removing heat, also keeps the fuelrods from becoming overheated.

•

Two steam generators, through which the heated water
passes and gives up its heat to convert cooler water in anotherclosed system to steam.

•

A steam turbine that drives a generator to produce electricity.

•

Pumps to circulate water through the various systems.

•

A pressurizer, a large tank that maintains the reactor
water at a pressure high enough to prevent boiling. At TMI-2,
the pressurizer tank usually holds 800 cubic feet of water and700 cubic feet of steam above it. The steam pressure is controlled by heating or cooling the water in the pressurizer.
The steam pressure, in turn, is used to control the pressureof the water cooling the reactor.
Normally, water to the TMI-2 reactor flows through a closed
system of pipes called the "reactor coolant system" or "primaryloop." The water is pushed through the reactor by four reactor
coolant pumps, each powered by a 9,000 horsepower electric motor.
In the reactor, the water picks up heat as it flows around each fuelThen it travels through 36-inch diameter, stainless steelrod.
pipes shaped like and called "candy canes," and into the steam
generators.

In the steam generators, a transfer of heat takes place. Thevery hot water from the reactor coolant system travels down throughthe steam generators in a series of corrosion-resistant tubes.
Meanwhile, water from another closed system -- the feedwater systemor "secondary loop" -- is forced into the steam generator.

The feedwater in the steam generators flows around the tubes
that contain the hot water from the reactor coolant system. Some ofthis heat is transferred to the cooler feedwater, which boils andJust as it would be in a coal- or oil-fired generating
becomes steam.
plant, the steam is carried from the two steam generators to turnthe steam turbine, which runs the electricity-producing generator.
88

ACCOUNT OF THE ACCIDENT
The water from the reactor coolant system, which has now lost
some of its heat, is pumped back to the reactor to pass around thefuel rods, pick up more heat, and begin its cycle again.
The water from the feedwater system, which has turned to steam
to drive the turbine, passes through devices called condensers.
Here, the steam is condensed back to water, and is forced back tothe steam generators again.
The condenser water is cooled in the cooling towers. The waterthat cools the condensers is also in a closed system or loop. It
cools the condensers, picks up heat, and is pumped to the cooling
towers, where it cascades along a series of steps. As it does, itreleases its heat to the outside air, creating the white vapor
plumes that drift skyward from the towers. Then the water is pumped
back to the condensers to begin its cooling process over again.
Neither the water that cools the condensers, nor the vapor
plumes that rise from the cooling towers, nor any of the water thatruns through the feedwater system is radioactive under normal conditions.
The water that runs through the reactor coolant system is radioactive,of course, since it has been exposed to the radioactive materials in
the core.
The turbine, the electric generator it powers, and most of thefeedwater system piping are outside the containment building inother structures. The steam generators, however, which must be fed
by water from both the reactor coolant and feedwater systems, areinside the containment building with the reactor and the pressurizertank.
A nuclear power facility is designed with many ways to protect
Each of its major systems has an automatic
against system failure.
backup system to replace it in the event of a failure. For example,
in a loss-of-coolant accident (LOCA) -- that is, an accident inwhich there is a loss of the reactor's cooling water -- the Emergency
Core Cooling System (ECCS) automatically uses existing plant equipment
to ensure that cooling water covers the core.
In a LOCA, such as occurred at TMI-2, a vital part of the ECCS
is the High Pressure Injection (HPI) pumps, which can pour about
1,000 gallons a minute into the core to replace cooling water being
lost through a stuck-open valve, broken pipe, or other type of leak.
But the ECCS can be effective only if plant operators allow it tokeep running and functioning as designed. At Three Mile Island,
they did not.

89

ACCOUNT OF THE ACCIDENTWEDNESDAY; MARCH 28
In the parlance of the electric power industry, a "trip" meansa piece of machinery stops operating. A series of feedwater system
pumps supplying water to TMI-2's steam generators tripped on themorning of March 28, 1979. The nuclear plant was operating at 97
percent power at the time. The first pump trip occurred at 36
When the pumps stopped, the flow of waterseconds after 4:00 a.m.
With no feedwater being added,
to the steam generators stopped.
there soon would be no steam, so the plant's safety system
automatically shut down the steam turbine and the electric generator
it powered. The incident at Three Mile Island was 2 seconds old.
The production of steam is a critical function of a nuclear
Not only does steam run the generator to produce
reactor.
electricity but also, as steam is produced, it removes some of theintense heat that the reactor water carries.
When the feedwater flow stopped, the temperature of the reactor
The rapidly heating water expanded. The
coolant increased.
pressurizer level (the level of the water inside the pressurizertank) rose and the steam in the top of the tank compressed. Pressure
inside the pressurizer built to 2,255 pounds per square inch, 100
psi more than normal. Then a valve atop the pressurizer, called apilot-operated relief valve, or PORV, opened -- as it was designed
to do -- and steam and water began flowing out of the reactor coolant
system through a drain pipe to a tank on the floor of the containmentbuilding. ll / Pressure continued to rise, however, and 8 seconds
after the first pump tripped, TMI-2's reactor -- as it was designed
to do -- scrammed: its control rods automatically dropped down into
the reactor core to halt its nuclear fission.
Less than a second later, the heat generated by fission wasessentially zero. But, as in any nuclear reactor, the decaying
radioactive materials left from the fission process continued toheat the reactor's coolant water. This heat was a small fraction -just 6 percent -- of that released during fission, but it was still
substantial and had to be removed to keep the core from overheating.
When the pumps that normally supply the steam generator with water90

ACCOUNT OF THE ACCIDENT
shut down, three emergency feedwater pumps automatically started.
Fourteen seconds into the accident, an operator in TMI-2's control
room noted the emergency feed pumps were running. He did not notice
two lights that told him a valve was closed on each of the two
emergency feedwater lines and thus no water could reach the steam
generators.
One light was covered by a yellow maintenance tag. No
one knows why the second light was missed.12/
With the reactor scrammed and the PORV open, pressure in thereactor coolant system fell.
Up to this point, the reactor system
was responding normally to a turbine trip. The PORV should haveclosed 13 seconds into the accident, when pressure dropped to 2,205
psi.
It did not.
A light on the control room panel indicated thatthe electric power that opened the PORV had gone off, leading theoperators to assume the valve had shut. 13 /But the PORV was stuck
open, and would remain open for 2 hours and 22 minutes, draining
needed coolant water -- a LOCA was in progress. In the first 100
minutes of the accident, some 32,000 gallons -- over one-third of
the entire capacity of the reactor coolant system -- would escapethrough the PORV and out the reactor's let-down system. Had thevalve closed as it was designed to do, or if the control room operators
had realized that the valve was stuck open and closed a backup valve
to stem the flow of coolant water, or if they had simply left on theplant's high pressure injection pumps, the accident at Three Mile
Island would have remained little more than a minor inconveniencefor Met Ed.
-0-0-0To a casual visitor, the control room at TMI-2 can be an intimidating place, with messages coming from the loudspeaker of theplant's paging system; panel upon panel of red, green, amber, andwhite lights; and alarms that sound or flash warnings many times
each hour.
Reactor operators are trained how to respond and torespond quickly in emergencies. Initial actions are ingrained,almost automatic and unthinking.14/
The burden of dealing with the early, crucial stages of theaccident at Three Mile Island fell to four men -- William Zewe,
shift supervisor in charge of both TMI-1 and TMI-2; Fred Scheimann,
shift foreman for TMI-2; and two control room operators, Edward
Frederick and Craig Faust. Each had been trained for his job by Met
Ed and Babcock & Wilcox, the company that supplied TMI-2's reactor
and nuclear steam system; each was licensed by the Nuclear Regulatory
Commission; each was a product of his training -- training that did
not adequately prepare them to cope with the accident at TMI-2. 15 /Indeed, their training was partly responsible for escalating whatshould have been a minor event into a potentially devastating accident.
Frederick and Faust were in the control room 16/ when the firstalarm sounded, followed by a cascade of alarms that numbered 100
The operators reacted quickly as trained to counter
within minutes.
the turbine trip and reactor scram. Later Faust would recall for
the Commission his reaction to the incessant alarms: "I would have
liked to have thrown away the alarm panel. It wasn't giving us any

91

ACCOUNT OF THE ACCIDENT

TMI-2 control room.

N

92

ACCOUNT OF THE ACCIDENT
useful information." 17 / Zewe, working in a small, glass-enclosed
office behind the operators, alerted the TMI-1 control room of theTMI-2 scram and called his shift foreman back to the control room.
Scheimann had been overseeing maintenance on the plant's
Number 7 polisher -- one of the machines that remove dissolved
minerals from the feedwater system. His crew was using a mixture of
air and water to break up resin that had clogged a resin transfer
Later investigation would reveal that a faulty valve in one
line.
of the polishers allowed some water to leak into the air-controlled
system that opens and closes the polishers' valves and may have beena factor in their sudden closure just before the accident began.
This malfunction probably triggered the initial pump trip that led
to the accident. The same problem of water leaking into thepolishers' valve control system had occurred at least twice before
at TMI-2. Had Met Ed corrected the earlier polisher problem, theMarch 28 sequence of events may never have begun.l8/-0-0-0With the PORV stuck open and heat being removed by the steam
generators, the pressure and temperature of the reactor coolant
The water level also fell in the pressurizer.
system dropped.
Thirteen seconds into the accident, the operators turned on a pumpto add water to the system. This was done because the water in thesystem was shrinking as it cooled. Thus more water was needed tofill the system. Forty-eight seconds into the incident, whilepressure continued falling, the water level in the pressurizer began
to rise again. The reason, at this point, was that the amount ofwater being pumped into the system was greater than that being lost
through the PORV.
About a minute and 45 seconds into the incident, because theiremergency water lines were blocked, the steam generators boiled dry.
After the steam generators boiled dry, the reactor coolant heated up
again, expanded, and this helped send the pressurizer level up
further.
Two minutes into the incident, with the pressurizer level stillrising, pressure in the reactor coolant system dropped sharply.
Automatically, two large pumps began pouring about 1,000 gallons aminute into the system. The pumps, called high pressure injection(HPI) pumps, are part of the reactor's emergency core cooling system.
The level of water in the pressurizer continued to rise, and theoperators, conditioned to maintain a certain level in thepressurizer, took this to mean that the system had plenty of waterin it.19/ However, the pressure of reactor coolant system water was
falling, and its temperature became constant.
About 2-/ minutes after the HPI pumps began working, Frederick
shut one down and reduced the flow of the second to less than
100 gallons per minute. The falling pressure, coupled with aconstant reactor coolant temperature after HPI came on, should haveclearly alerted the operators that TMI-2 had suffered a LOCA, andsafety required they maintain high pressure injection. "The rapidly

93ACCOUNT OF THE ACCIDENT
increasing pressurizer level at the onset of the accident led me tobelieve that the high pressure injection was excessive, and that wewere soon going to have a solid system," Frederick later told theCommission.20/
A solid system is one in which the entire reactor and its
cooling system, including the pressurizer, are filled with water.
The operators had been taught to keep the system from "going solid"
a condition that would make controlling the pressure within thereactor coolant system more difficult and that might damage the
The operators followed this line of reasoning, oblivious
system.
for over 4 hours to a far greater threat -- that the loss of waterfrom the system could result in uncovering the core.21/
The saturation point was reached 5-~ minutes into the accident.
Steam bubbles began forming in the reactor coolant system, displacing
the coolant water in the reactor itself. The displaced water moved
into the pressurizer, sending its level still higher. This continued
to suggest to the operators that there was plenty of water in the
They did not realize that water was actually flashing into
system.
steam in the reactor, and with more water leaving the system thanbeing added, the core was on its way to being uncovered. 22 / And so
the operators began draining off the reactor's cooling water throughpiping called the let-down system.
Eight minutes into the accident, someone -- just who is amatter of dispute -- discovered that no emergency feedwater was
Operator Faust scanned the lights onreaching the steam generators.
the control panel that indicate whether the emergency feedwater
valves are open or closed. He first checked a set of emergency
feedwater valves designed to open after the pumps reach full speed;
they were open. Next he checked a second pair of emergency feedwater
valves, called the "twelve-valves," which are always supposed to beopen, except during a specific test of the emergency feedwater
pumps. The two "twelve-valves" were closed. Faust opened them andwater rushed into the steam generators.23/
The two "twelve-valves" were known to have been closed 2 days
earlier, on March 26, as part of a routine test of the emergency
A Commission investigation has not identified afeedwater pumps.
specific reason as to why the valves were closed at 8 minutes into
The most likely explanations are: the valves were
the accident.
never reopened after the March 26 test; or the valves were reopened
and the control room operators mistakenly closed the valves during
the very first part of the accident; or the valves were closed
mistakenly from control points outside the control room after the
test. The loss of emergency feedwater for 8 minutes had no significant
effect on the outcome of the accident. 24 / But it did add to theconfusion that distracted the operators as they sought to understandthe cause of their primary problem.
Throughout the first 2 hours of the accident, the operators
ignored or failed to recognize the significance of several things
that should have warned them that they had an open PORV and a lossof-coolant accident.
One was the high temperatures at the94

ACCOUNT OF THE ACCIDENT

TMI-2 control room operators testifying before the Commission.
Seated (1 to r) are Ernest Blake, legal counsel to Met Ed, and operators
Fred Scheimann, William Zewe, Edward Frederick, and Craig Faust.

95

ACCOUNT OF THE ACCIDENT
drain pipe that led from the PORV to the reactor coolant drain tank.
One emergency procedure states that a pipe temperature of 200°F
indicates an open PORV. Another states that when the drain pipe
temperature reaches 130 ° F, the block valve beneath it should beclosed. 25 / But the operators testified that the pipe temperaturenormally registered high because either the PORV or some other valve
was leaking slightly.
"I have seen, in reviewing logs since theaccident, approximately 198 degrees," Zewe told the Commission.
"But I can remember instances before . . . just over 200 degrees."26/
So Zewe and his crew dismissed the significance of the temperature
readings, which Zewe recalled as being in the 230 ° F range.
Recordeddata show the range reached 285°F. Zewe told the Commission that heregarded the high temperatures on the drain pipe as residual heat:". . .[K]nowing that the relief valve had lifted, the downstream
temperature I would expect to be high and that it would take sometime for the pipe to cool down below the 200-degree set point."27/-0-0-0At 4:11 a.m., an alarm signaled high water in the containmentbuilding's sump, a clear indication of a leak or break in the system.
The water, mixed with steam, had come from the open PORV, first
falling to the drain tank on the containment building floor andfinally filling the tank and flowing into the sump. At 4:15 a.m., arupture disc on the drain tank burst as pressure in the tank rose.
This sent more slightly radioactive water onto the floor and into
the sump.
From the sump it was pumped to a tank in the nearby
auxiliary building.
Five minutes later, at 4:20 a.m., instruments measuring theneutrons inside the core showed a count higher than normal, anotherindication -- unrecognized by the operators -- that steam bubbles
were present in the core and forcing cooling water away from thefuel rods. During this time, the temperature and pressure inside
the containment building rose rapidly from the heat and steam
escaping via the PORV and drain tank. The operators turned on thecooling equipment and fans inside the containment building. The
fact that they failed to realize that these conditions resulted froma LOCA indicates a severe deficiency in their training to identify
the symptoms of such an accident.28/
About this time, Edward Frederick took a call from the auxiliarybuilding. He was told an instrument there indicated more than 6feet of water in the containment building sump. Frederick queried
the control room computer and got the same answer. Frederick
recommended shutting off the two sump pumps in the containmentbuilding.
He did not know where the water was coming from and did
not want to pump water of unknown origin, which might be radioactive,
outside the containment building.29/ Both sump pumps were stopped
about 4:39 a.m. Before they were, however, as much as 8,000 gallons
of slightly radioactive water may have been pumped into the auxiliarybuilding.30/ Only 39 minutes had passed since the start of theaccident.
96

ACCOUNT OF THE ACCIDENT

Control panel of TMI-2, showing maintenance tags that operators
testified covered one of the closed emergency feedwater valve
indicator lights during the first 8 minutes of the accident.

., I

97

ACCOUNT OF THE ACCIDENT

Gary Miller (1), station manager of TMI, and George Kunder (r),TMI-2's superintendent for technical support, testifying before
the Commission.

98

ACCOUNT OF THE ACCIDENT-0-0-0-George Kunder, superintendent of technical support at TMI-2,
arrived at the Island about 4:45 a.m., summoned by telephone.
Kunder was duty officer that day, and he had been told TMI-2 had had
a turbine trip and reactor scram. What he found upon his arrival
was not what he expected. "I felt we were experiencing a very
unusual situation, because I had never seen pressurizer level gohigh and peg in the high range, and at the same time, pressure being
low," he told the Commission. "They have always performed
consistently." 31 / Kunder's view was shared by the control roomcrew.
They later described the accident as a combination of events
they had never experienced, either in operating the plant or in
their training simulations.32/
Shortly after 5:00 a.m., TMI-2's four reactor coolant pumps
began vibrating severely.
This resulted from pumping steam as wellas water, and it was another indication that went unrecognized thatthe reactor's water was boiling into steam. The operators feared
the violent shaking might damage the pumps -- which force water tocirculate through the core -- or the coolant piping.33/
Zewe and his operators followed their training. At 5:14 a.m.,
two of the pumps were shut down. Twenty-seven minutes later,
operators turned off the two remaining pumps, stopping the forced
flow of cooling water through the core.
There was already evidence by approximately 6:00 a.m. that atleast a few of the reactor's fuel rod claddings had ruptured fromhigh gas pressures inside them, allowing some of the radioactive
gases within the rods to escape into the coolant water. The early
warning came from radiation alarms inside the containment building.
With coolant continuing to stream out the open PORV and little water
being added, the top of the core became uncovered and heated to thepoint where the zirconium alloy of the fuel rod cladding reactedwith steam to produce hydrogen. Some of this hydrogen escaped into
the containment building through the open PORV and drain tank; someof it remained within the reactor. This hydrogen, and possiblyhydrogen produced later in the day, caused the explosion in thecontainment building on Wednesday afternoon and formed the gas
bubble that produced such great concern a few days later.34/
Other TMI officials now were arriving in the TMI-2 control
room.
They included Richard Dubiel, a health physicist who served
as supervisor of radiation protection and chemistry; Joseph Logan,superintendent of TMI-2; and Michael Ross, supervisor of operations
for TMI-1.
Shortly after 6:00 a.m., George Kunder participated in a
telephone conference call with John Herbein, Met Ed's vice president
for generation; Gary Miller, TMI station manager and Met Ed's senior
executive stationed at the nuclear facility; and Leland Rogers, theBabcock & Wilcox site representative at TMI. The four men discussed
the situation at the plant. In his deposition, Rogers recalled asignificant question he posed during that call: He asked if theblock valve between the pressurizer and the PORV, a backup valve

99

ACCOUNT OF THE ACCIDENT
that could be closed if the PORV stuck open, had been shut.
QUESTION:

What was the response?

ROGERS:
George's immediate response was, "I don't know,"and he had someone standing next to the shift supervisor overback of the control room and sent the guy to find out if thevalve block was shut.
QUESTION: You heard him give these instructions?
ROGERS:
Yes, and very shortly I heard the answer come backfrom the other person to George, and he said, "Yes, the block
valve was shut. . . ."35/
The operators shut the block valve at 6:22 a.m., 2 hours and22 minutes after the PORV had opened.
It remains, however, an open question whether Rogers or someone
else was responsible for the valve being closed. Edward Frederick
testified that the valve was closed at the suggestion of a shift
supervisor coming onto the next shift; but Frederick has also
testified that the valve was closed because he and his fellow
operators could think of nothing else to do to bring the reactor
back under control.36/
In any event, the loss of coolant was stopped, and pressure
began to rise, but the damage continued. Evidence now indicates thewater in the reactor was below the top of the core at 6:15 a.m. Yetfor some unexplained reason, high pressure injection to replace thewater lost through the PORV and let-down system was not initiatedfor almost another hour. Before that occurred, Kunder, Dubiel, andtheir colleagues would realize they faced a serious emergency at
TMI-2.
In the 2 hours after the turbine trip, periodic alarms warnedof low-level radiation within the unoccupied containment building.
After 6:00 a.m., the radiation readings markedly increased. About
6:30 a.m., a radiation technician began surveying the TMI-2
auxiliary building, using a portable detector -- a task that took
about 20 minutes. He reported rapidly increasing levels ofradiation, up to one rem per hour. During this period, monitors in
the containment and auxiliary buildings showed rising radiationlevels. By 6:48 a.m., high radiation levels existed in several
areas of the plant, and evidence indicates as much as two-thirds ofthe 12-foot high core stood uncovered at this time. Analyses andcalculations made after the accident indicate temperatures as highas 3,500 to 4,000°F or more in parts of the core existed during its
maximum uncovery. 37 / At 6:54 a.m., the operators turned on one of
the reactor coolant pumps, but shut it down 19 minutes later becauseof high vibrations.
More radiation alarms went off. Shortly before
7:00 a.m., Kunder and Zewe declared a site emergency, required by
TMI's emergency plan whenever some event threatens "an uncontrolled
release of radioactivity to the immediate environment."38/-0-0-0-10 0

ACCOUNT OF THE ACCIDENT
Gary Miller, TMI station manager, arrived at the TMI-2 control
room a few minutes after 7:00 a.m. Radiation levels were increasing
throughout the plant.
Miller had first learned of the turbine trip
and reactor scram within minutes after they occurred. He had had
several telephone conversations with people at the site, including
the 6:00 a.m. conference call. When he reached Three Mile Island,
Miller found that a site emergency existed. He immediately assumedcommand as emergency director and formed a team of senior employees
to aid him in controlling the accident and in implementing TMI-2's
emergency plan.39/
Miller told Michael Ross to supervise operator activities in
the TMI-2 control room. Richard Dubiel directed radiation activities,
including monitorings on- and off-site.
Joseph Logan was charged
with ensuring that all required procedures and plans were reviewed
and followed. George Kunder took over technical support andcommunications.
Daniel Shovlin, TMI's maintenance superintendent,
directed emergency maintenance.
B&W's Leland Rogers was asked toprovide technical assistance and serve as liaison with his homeoffice. Miller gave James Seelinger, superintendent of TMI-1,
charge of the emergency control station set up in the TMI-1 control
room. 40 / Under TMI's emergency plan, the control room of the unit
not involved in an accident becomes the emergency control station.
On March 28, TMI-1 was in the process of starting again after being
shut down for refueling of its reactor.
TMI personnel were already following the emergency plan,
telephoning state authorities about the site emergency. 41 / The
Pennsylvania Emergency Management Agency (PEMA) was asked to notify
the Bureau of Radiation Protection (BRP), part of Pennsylvania's
Department of Environmental Resources.
The bureau in turn telephoned
Kevin Molloy, director of the Dauphin County Office of Emergency
Preparedness.
Dauphin County includes Harrisburg and Three Mile
Island.
Other nearby counties and the State Police were alerted.
Met Ed alerted the U.S. Department of Energy's Radiological
Assistance Plan office at Brookhaven National Laboratory. But
notifying the Nuclear Regulatory Commission's Region I office inKing of Prussia, Pennsylvania, took longer. The initial phone callreached an answering service, which tried to telephone the NRC duty
officer and the region's deputy director at their homes. Both wereen route to work.
By the time the NRC learned of the accident -- when its Region I
office opened at 7:45 a.m. -- Miller had escalated the site emergency
at Three Mile Island to a general emergency. Shortly after 7:15 a.m.,emergency workers had to evacuate the TMI-2 auxiliary building.
William Dornsife, a nuclear engineer with the Pennsylvania Bureau of
Radiation Protection, was on the telephone to the TMI-2 control roomat the time. He heard the evacuation ordered over the plant's
paging system.
"And I said to myself, 'This is the biggie,'"
Dornsife recalled in his deposition.42/
At 7:20 a.m., an alarm indicated that the radiation dome monitor
high in the containment building was reading 8 rems per hour. The

10 1

ACCOUNT OF THE ACCIDENT
monitor is shielded by lead. This shielding is designed to cut theradioactivity reaching the monitor by 100 times. Thus, those in thecontrol room interpreted the monitor's alarm as meaning that theradiation present in the containment building at the time was about
800 rems per hour. Almost simultaneously, the operators finallyturned on the high pressure injection pumps, once again dumping
water into the reactor, but this intense flow was kept on for only
18 minutes.
Other radiation alarms sounded in the control room.
Gary Miller declared a general emergency at 7:24 a.m. By definition,
at Three Mile Island, a general emergency is an "incident which has
the potential for serious radiological consequences to the healthand safety of the general public."43/
As part of TMI's emergency plan, state authorities were again
notified and teams were sent to monitor radiation on the Island andashore. The first team, designated Alpha and consisting of two
radiation technicians, was sent to the west side of the Island, thedownwind direction at the time. Another two-man team, designatedCharlie, left for Goldsboro, a community of some 600 persons on thewest bank of the Susquehanna River across from Three Mile Island.
Meanwhile, a team sent into the auxiliary building reported increasingradiation levels and the building's basement partly flooded withwater.
At 7:48 a.m., radiation team Alpha reported radiation levels
along the Island's west shoreline were less than one millirem perhour. Minutes later, another radiation team reported similar readings
at the Island's north gate and along Route 441, which runs parallelto the Susquehanna's eastern shore.
-0-0-0Nearly 4 hours after the accident began, the containment building
automatically isolated.
Isolation is intended to help prevent
radioactive material released by an accident from escaping into theenvironment. The building is not totally closed off. Pipes carrying
coolant run between the containment and auxiliary buildings. These
pipes close off when the containment building isolates, but theoperators can open them. This occurred at TMI-2 and radioactive
water flowed through these pipes even during isolation. Some ofthis piping leaked radioactive material into the auxiliary building,some of which escaped from there into the atmosphere outside.44/
In September 1975, the NRC instituted its Standard Review Plan,
which included new criteria for isolation. The plan listed three
conditions -- increased pressure, rising radiation levels, andemergency core cooling system activation -- and required that
containment buildings isolate on any two of the three. However, theplan was not applied to nuclear plants that had already received
their construction permits. TMI-2 had, so it was "grandfathered"and not required to meet the Standard Review Plan, although theplant had yet to receive its operating license.45/
In the TMI-2 design, isolation occurred only when increasingpressure in the containment building reached a certain point, nominally
4 pounds per square inch. Radiation releases alone, no matter how
intense, would not initiate isolation, nor would ECCS activation.46/
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ACCOUNT OF THE ACCIDENT
Although large amounts of steam entered the containment building
early in the TMI-2 accident through the open PORV, the operators had
kept pressure there low by using the building's cooling and ventilation
But the failure to isolate early made little difference insystem.
the TMI-2 accident. Some of the radioactivity ultimately released
into the atmosphere occurred after isolation from leaks in thelet-down system that continued to carry radioactive water out of thecontainment building into the auxiliary building.47/
At 8:26 a.m., the operators once again turned on the ECCS's
high pressure injection pumps and maintained a relatively high rateof flow.
The core was still uncovered at this time and evidence
indicates it took until about 10:30 a.m. for the HPI pumps to fully
cover the core again.
By 7:50 a.m., NRC Region I officials had established direct
telephone contact with the TMI-2 control room. Ten minutes later,
Region I activated its Incident Response Center at King of Prussia,
opened a direct telephone line to the Emergency Control Station in
the TMI-1 control room, and notified NRC staff headquarters in
Bethesda, Maryland.
Region I officials gathered what information
they could and relayed it to NRC headquarters, which had activatedits own Incident Response Center. Region I dispatched two teams ofinspectors to Three Mile Island; the first left at about 8:45 a.m.,the second a few minutes later.
Around 8:00 a.m., it was clear to Gary Miller that the TMI-2
reactor had suffered some fuel damage. The radiation levels told
him that. Yet Miller would testify to the Commission: ". . . I
don't believe in my mind I really believed the core had been totally
uncovered, or uncovered to a substantial degree at that time."48/
Off the Island, radiation readings continued to be encouragingly
Survey team Charlie reported no detectable radiation in Goldsboro.
low.
Miller and several aides concluded about 8:30 a.m. that the emergency
plan was being properly implemented.
-0-0-0WKBO, a Harrisburg "Top 40" music station, broke the story of
TMI-2 on its 8:25 a.m. newscast. The station's traffic reporter,
known as Captain Dave, uses an automobile equipped with a CB radio
About 8:00 a.m. he heard police and fireto gather his information.
fighters were mobilizing in Middletown and relayed this to his
Mike Pintek, WKBO's news director, called Three Milestation.
Island and asked for a public relations official. He was connected
instead with the control room to a man who told him: "I can't talknow, we've got a problem." The man denied that "there are any fireengines," and told Pintek to telephone Met Ed's headquarters in
Reading, Pennsylvania.
Pintek did, and finally reached Blaine Fabian, the company's
manager of communications services. In an interview with the Commission
staff, Pintek told what happened next:
10 3

ACCOUNT OF THE ACCIDENT
Fabian came on and said there was a general emergency. Whatthe hell is that? He said that general emergency was a "red-tape"
type of thing required by the NRC when certain conditions
What conditions? "There was a problem with a feedwater
exist.
The plant is shut down. We're working on it. There'spump.
No danger to the general public." Andno danger off-site.
that is the story we went with at 8:25. I tried to tone it
down so people wouldn't be alarmed.49/
At 9:06 a.m., the Associated Press filed its first story -- abrief dispatch teletyped to newspaper, television, and radio news
rooms across the nation. The article quoted Pennsylvania State
Police as saying a general emergency had been declared, "there is noradiation leak," and that Met Ed officials had requested a State
Police helicopter "that will carry a monitoring team." The story
contained only six sentences in four paragraphs, but it alerted
editors to what would become one of the most heavily reported news
stories of 1979.50/
Many public officials learned of the accident from the news
media, rather than from the state, or their own emergency preparedness
people. Harrisburg Mayor Paul Doutrich was one, and that still
rankled him when he testified before the Commission 7 weeks later.
Doutrich heard about the problem in a 9:15 a.m. telephone call froma radio station in Boston. "They asked me what we were doing about
the nuclear emergency," Doutrich recalled. "My response was, 'What
They said, 'Well, at Three Mile Island.' I
nuclear emergency?'
said, 'I know nothing about it. We have a nuclear plant there, but
I know nothing about a problem.' So they told me; a Boston radio
station."51/-0-0-0At 9:15 a.m., the NRC notified the White House of the events atThree Mile Island. Seven minutes later, an air sample taken inGoldsboro detected low levels of radioactive iodine-131. This
specific reading was erroneous; a later, more sensitive analysis of
the sample found no iodine-131. At 9:30 a.m., John Herbein, Met
Ed's vice president for generation, was ordered to Three Mile Islandfrom Philadelphia by Met Ed President Walter Creitz. And at 10:05 a.m.,the first contingent of NRC Region I officials arrived at Three Mile
Island.
In the days to follow, the NRC would dominate the public's
perception of the events at Three Mile Island. But the initial NRC
team consisted of only five Region I inspectors, headed by
The five were briefed in the TMI-1 control room on
Charles Gallina.
the status of TMI-2. Then Gallina sent two inspectors into the
TMI-2 control room and two more out to take radiation measurements;
he himself remained in the TMI-1 control room to coordinate theirreports and relay information to both Region I and NRC headquarters.52/
While the NRC team received its briefing, monitors indicatedthat radiation levels in the TMI-2 control room had risen above theWorkers put onlevels considered acceptable in NRC regulations.

10 4

ACCOUNT OF THE ACCIDENTJohn Herbein (1), Met Ed vice president for generation, andWalter Creitz (r), Met Ed president, at a March 29 press conference.

10 5

ACCOUNT OF THE ACCIDENT
protective face masks with filters to screen out any airborne radioactive
particles.
This made communications among those managing the accident
At 11:00 a.m., all nonessential personnel were ordereddifficult.
off the Island. At the same hour, both Pennsylvania's Bureau of
Radiation Protection and the NRC requested the Department of Energy
to send a team from Brookhaven National Laboratory to assist inmonitoring environmental radiation.53/
About this time, Mayor Robert Reid of Middletown telephoned Met
Ed's home office in Reading. He was assured, he later told theCommission, that no radioactive particles had escaped and no one wasinjured.
I felt relieved and relaxed; I said, "There's no problem."Twenty seconds later I walked out of my office and got in mycar and turned the radio on and the announcer told me, over
the radio, that there were radioactive particles released.
Now, I said, "Gee whiz, what's going on here?" At 4:00 in theafternoon the same day the same man called me at home andsaid, "Mayor Reid, I want to update our conversation that we
had at 11:00 a.m." I said, "Are you going to tell me that[ radioactive] particles were released?" He said, "Yes." I
said, "I knew that 20 seconds after I spoke to you on thephone."54/Throughout much of the morning, Pennsylvania's Lieutenant
Governor William Scranton, III, focused his attention on Three Mile
Scranton was charged, among other things, with overseeing
Island.
He had planned athe state's emergency preparedness functions.
morning press conference on energy conservation, but when he finally
faced reporters in Harrisburg, the subject was TMI-2. 55 / In a brief
opening statement, Scranton said:
The Metropolitan Edison Company has informed us that there has
been an incident at Three Mile Island, Unit-2. Everything is
There is and was no danger to public healthunder control.
and safety. . . . There was a small release of radiation to
the environment.
All safety equipment functioned properly.
Metropolitan Edison has been monitoring the air in the vicinityof the plant constantly since the incident. No increase innormal radiation levels has been detected . . . .56/
During the questioning by reporters, however, William Dornsifeof the state's Bureau of Radiation Protection, who was there at
Scranton's invitation, said Met Ed employees had "detected a small
amount of radioactive iodine. . . ." Dornsife had learned of theiodine reading (later found to be in error) just before the press
conference began and had not had time to tell Scranton. Dornsife
dismissed any threat to human health from the amount of radioactive
iodine reported in Goldsboro.57/
Shortly after the press conference, a reporter told Scrantonthat Met Ed in Reading denied any off-site radiation. While somecompany executives were acknowledging radiation readings off theIsland, low-level public relations officials at Met Ed's headquarters

106

ACCOUNT OF THE ACCIDENT
continued until noon to deny any off-site releases. It was an error
in communications within Met Ed, one of several that would reduce
the utility's credibility with public officials and the press.
"This was the first contradictory bit of information that we received
and it caused some disturbance," Scranton told the Commission in his
testimony-58/-0-0-0At Three Mile Island, the control room was crowded with operatorsand supervisors trying to bring the plant under control. They had
failed in efforts to establish natural circulation cooling. Thisessentially means setting up a flow of water, without mechanicalassistance, by heating water in the core and cooling it in the steam
generators.
This effort failed because the reactor coolant system
was not filled with water and a gas bubble forming in the top of thereactor blocked this flow of water. At 11:38 a.m., operators began
to decrease pressure in the reactor system. The pressurizer block
valve was opened and high pressure injection cut sharply. This
resulted again in a loss of coolant and an uncovering of the core.
The depressurization attempt ended at 3:08 p.m.59/ The amount andduration of core uncovery during this period remains unknown.
About noon, three employees entered the auxiliary building andfound radiation levels ranging from 50 millirems to 1,000 rems (onemillion millirems) an hour. Each of the three workers received an
800-millirem dose during the entry. 60 / At 12:45 p.m., the Pennsylvania
State Police closed Route 441 to traffic near Three Mile Island at
the request of the state's Bureau of Radiation Protection. An hourlater, the U.S. Department of Energy team began its first helicopter
flight to monitor radiation levels. And at 1:50 p.m., a noise
penetrated the TMI-2 control room; "a thud," as Gary Miller later
characterized it.61/
That thud was the sound of a hydrogen explosion inside thecontainment building.
It was heard in the control room; its forceof 28 pounds per square inch was recorded on a computer strip chart
there, which Met Ed's Michael Ross examined within a minute or
two.62/ Yet Ross and others failed to realize the significance ofthe event.
Not until late Thursday was that sudden and brief risein pressure recognized as an explosion of hydrogen gas released fromthe reactor.
The noise, said B&W's Leland Rogers in his deposition,
was dismissed at the time as the slamming of a ventilation damper. 63 /And the pressure spike on the strip chart, Ross explained to theCommission, "we kind of wrote it off . . . [as] possibly instrument
malfunction. . . ."64/
Miller, Herbein, and Kunder left for Harrisburg soon afterwards
for a 2:30 p.m. briefing with Lieutenant Governor Scranton on theevents at Three Mile Island. At 2:27 p.m., radiation readings in
Middletown ranged from 1 to 2 millirems per hour.65/-0-0-0The influx of news media from outside the Harrisburg area began
during the afternoon.
The wire service reports of Associated Press

10 7

ACCOUNT OF THE ACCIDENT

TMI-2 control room several days after the start of the accident.
The man in the foreground wearing a helmet is Charles Gallina, NRC
inspector from Region I. The two men above Gallina are Craig Faust
and William Zewe, both of whom were on duty when the accident began.

10 8

ACCOUNT OF THE ACCIDENT
and United Press International had alerted editors here and abroadto the accident. The heavy flow of newspaper and magazine reporters,
television and radio correspondents, and photographers and cameracrews would come later as the sense of concern about Three Mile
Island grew.
But at 4:30 p.m., when Scranton once more met thepress, he found some strange faces among the familiar crew ofcorrespondents who regularly covered Pennsylvania's Capitol.
Scranton had discussed the TMI situation with his own people
and listened to Met Ed officials. "I wouldn't say that they [Met Ed]
were exactly helpful, but they were not obstructive," he later
testified.
"I think they were defensive." Scranton was disturbed
by, among other things, Herbein's comment during their 2:30 p.m.
meeting that Herbein had not told reporters about some radiation
releases during an earlier Met Ed press conference because "itdidn't come up."66/ So Scranton was less assured about conditionsat Three Mile Island when he issued his afternoon statement to thepress:
This situation is more complex than the company first led us
to believe. We are taking more tests. And at this point, we
believe there is still no danger to public health. Metropolitan
Edison has given you and us conflicting information. We justconcluded a meeting with company officials and hope thisbriefing will clear up most of your questions. There has beena release of radioactivity into the environment. The magnitudeof the release is still being determined, but there is noevidence yet that it has resulted in the presence of dangerous
levels.
The company has informed us that from 11:00 a.m.
until about 1:30 p.m., Three Mile Island discharged into theair, steam that contained detectable amounts of radiation. . . .67/
Scranton's statement inappropriately focused public attention
on the steam emissions from TMI-2 as a source of radiation. In
fact, they were not, since the water that flows inside the towers isin a closed loop and cannot mix with water containing radioactive
materials unless there is a leak in the system.
Scranton went on to discuss potential health effects of theradiation releases:
The levels that were detected were below any existing or
proposed emergency action levels.
But we are concerned
because any increased exposure carries with it some increased
health risks.
The full impact on public health is being
evaluated as environmental samples are analyzed.
We areconcerned most about radioactive iodine, which can accumulate
in the thyroid, either through breathing or through drinking
milk.
Fortunately, we don't believe the risk is significant
because most dairy cows are on stored feed at this time ofyear.68/
Many Americans learned about the accident at Three Mile Islandfrom the evening newscasts of the television networks. Millions,
10 9

ACCOUNT OF THE ACCIDENT

Lieutenant Governor William Scranton (1) and Oran Henderson (r),director of the Pennsylvania Emergency Management Agency, at aMarch 28 press conference.

11 0

ACCOUNT OF THE ACCIDENT
for example, watched as Walter Cronkite led off the CBS EveningNews:
It was the first step in a nuclear nightmare; as far as weknow at this hour, no worse than that. But a government
official said that a breakdown in an atomic power plant in
Pennsylvania today is probably the worst nuclear accident
to date. . . .
At 7:30 p.m., Mayor Ken Myers of Goldsboro met with the boroughcouncil to discuss the accident and the borough's evacuation plan.
Then Myers suggested he and the council members go door-to-door totalk with residents of the small community.
Everyone listened to what we had to say. We mainly told themof what we had heard through the radio, TV, and even our own
public relations and communications department in the basementof the York County court house. . . . Then we told them alsoof our evacuation plans in case the Governor would declare an
emergency and that we would all have to leave. Of course,right away they gave us questions: "Well, what should we do?
Do you think it's safe that we should stay or do you think weshould go?" The ones that I talked to, I told them: "Useyour own judgment.
We dare not tell you to leave your homes."69/

III

ACCOUNT OF THE ACCIDENTTHURSDAY, MARCH 29
In retrospect, Thursday seemed a day of calm. A sense of
betterment, if not well-being, was the spirit for much of the day.
Radiation levels remained high at points within the auxiliary building,but off-site readings indicated no problems. The log book kept by
the Dauphin County Office of Emergency Preparedness reflects thismood of a crisis passing:
5:45 a.m.

Called Pennsylvania Emergency Management Agency
Blaisdale, reactor remains under control morestable than yesterday, not back to normal,
monitoring continues by Met Ed, Radiological
Health, and Nuclear Regulatory Commission.

7:55 a.m.

Pennsylvania Emergency Management Agency -. . . no danger to public.

11:25 a.m.

Pennsylvania Emergency Management Agency advised
situation same.

3:30 p.m.

.

.

situation is improving.

6:12 p.m.

. . . no change -- not cold yet, continues toimprove, slow rate, off-site release controlled.

7:00-9:00 p.m.

. . . Pennsylvania Emergency Management says
Island getting better.

9:55 p.m.

. . . no real measureable reading off-site -no health risk off-site, no emergency, bringing
reactor to cold shut down. . . .70/

Midmorning readings showed 5
Radiation monitoring continued.
to 10 millirems an hour on-site and 1 to 3 millirems per hour acrossthe Susquehanna River to the west. No radioactive iodine was detectedin the air. The U.S. Food and Drug Administration began monitoring
food, milk, and water in the area for radiation contamination.71/

11 2

ACCOUNT OF THE ACCIDENT

Sen. Gary Hart (1), Sen. Alan Simpson (c), and Rep. Allen Ertel(r) arrive at TMI for a briefing on the accident, March 29.
a

P

:-t

1

11 3

ACCOUNT OF THE ACCIDENT
Thursday was a day of questioning. NRC Chairman Joseph Hendrie
and several key aides journeyed to Capitol Hill to brief the House
Subcommittee on Energy and the Environment and other members of Congress on the accident. Lieutenant Governor Scranton spent several
hours in the early afternoon at Three Mile Island, touring the TMI-2
control room and auxiliary building, wearing a radiation suit andrespirator during part of his inspection. That same afternoon,
Met Ed officials and NRC inspectors briefed several visiting membersof Congress, including Rep. Allen Ertel (D-Pa.), whose district
includes Three Mile Island, and Sen. John Heinz (R-Pa.). Later inthe day, a second Congressional delegation that included Sen.
Richard Schweiker (R-Pa.) and Rep. William Goodling (R-Pa.), whose
district includes York, Adams, and Cumberland counties, received abriefing.
Thursday was also a day of disquieting discussions and discoveries.
Thursday afternoon, a telephone conversation took place between two
old acquaintances, Gordon MacLeod, Pennsylvania's Secretary of
Health, and Anthony Robbins, director of the National Institute for
One important point of that conversation
Occupational Safety and Health.
MacLeod recalls that Robbins urged him toremains in dispute.
recommend an evacuation of people living around Three Mile Island. 72 /Robbins denies discussing or suggesting such an evacuation.73
Up to this point, MacLeod -- who had taken office only 12 days
before the accident -- had offered no recommendations since his
department had no direct responsibility for radiological healthNow, however, he arranged a conference telephone call withmatters.
Oran Henderson, director of the Pennsylvania Emergency Management
Agency; Thomas Gerusky, director of the Bureau of Radiation Protection;
and John Pierce, an aide to Lieutenant Governor Scranton. MacLeod
told them Robbins had strongly recommended evacuation. The others
rejected the idea, although they agreed it should be reconsidered if
conditions proved worse than they appeared at TMI-2. MacLeod thenasked if it might be wise to have pregnant women and children underage 2 leave the area around the nuclear plant. This, too, wasrejected Thursday afternoon.74/
At 2:10 p.m., a helicopter over TMI-2 detected a brief burst ofradiation that measured 3,000 millirems per hour 15 feet above theplant's vent.
This information was relayed to NRC headquarters,
where it created no great concern.
But another release that afternoon, one within NRC limits forradiation releases, did cause considerable consternation.
Soon
after the accident began Wednesday, Met Ed stopped discharging
wastewater from such sources as toilets, showers, laundry facilities,
and leakage in the turbine and control and service buildings into
the Susquehanna River.
Normally, this water contains little or noradioactivity, but as a result of the accident, some radioactive
gases had contaminated it. The radiation levels, however, were
within the limits set by the NRC. By Thursday afternoon, nearly
400,000 gallons of this slightly radioactive water had accumulated
and the tanks were now close to overflowing. Two NRC officials -Charles Gallina on-site and George Smith at the Region I office --11 4

ACCOUNT OF THE ACCIDENT
told Met Ed they had no objections to releasing the water so long as
it was within NRC specifications. Met Ed notified the Bureau of
Radiation Protection and began dumping the wastewater. No communities
downstream from the plant were informed, nor was the press.75/
When NRC Chairman Hendrie learned of the release, he ordered it
stopped.
Hendrie did not know the water's source, and he was concerned
about the impact on the public of the release of any radiation, no
matter how slight. 76 / Some 40,000 gallons had entered the riverwhen the dumping ceased around 6:00 p.m. Both NRC officials on-site
and the Governor's aides realized that authorizing release of thewastewater would be unpopular, and neither was eager to do so. Yet
the tanks still were close to overflowing. After hours of discussion,agreement was reached on the wording of a press release that thestate's Department of Environmental Resources issued, which said DER"reluctantly agrees that the action must be taken." Release of thewastewater resumed shortly after midnight.77/
Late Thursday afternoon, Governor Thornburgh had held a press
conference. At it, the NRC's Charles Gallina told reporters thedanger was over for people off the Island. Thornburgh distrusted
the statement at the time, and events soon confirmed his suspicion.
At 6:30 p.m., Gallina and James Higgins, an NRC reactor inspector,
received the results of an analysis of the reactor's coolant water.
It showed that core damage was far more substantial than either had
anticipated.
At 10:00 p.m., Higgins telephoned the Governor's
office with the new information and indicated that a greater possibilityof radiation releases existed. Nothing had changed inside theplant, only NRC's awareness of the seriousness of the damage. Yet
Higgins' call foretold events only hours away.78/

11 5

ACCOUNT OF THE ACCIDENTERIDAY, MARCH 30
The TMI-2 reactor has a means of removing water from the reactor
coolant system, called the let-down system, and one for adding
water, called the make-up system. Piping from both runs through the
TMI-2 auxiliary building, and NRC officials suspected that leaks inthese two systems explained the sporadic, uncontrolled releases ofThey were also concerned about levels in the make-up
radioactivity.
tank and the two waste gas decay tanks inside the auxiliary building
Water from the let-down system flows into the make-up tank. In thattank, gases dissolved in the reactor's cooling water at high pressure
are released because the tank's pressure is lower, much as the gas
bubbles in a pressurized carbonated beverage appear when the bottle
These gases, under normal circumstances, are compressedis opened.
and stored in the waste gas decay tanks. NRC officials worried that
if the waste gas decay tanks filled to capacity, relief valves would
open, allowing a continuing escape of radiation into the environment.79/
That concern and what Commission Chairman Kemeny would later call a"horrible coincidence" 80 / resulted in a morning of confusion,
contradictory evacuation recommendations, and eventually an evacuation
advisory from Governor Richard Thornburgh.
About halfway through his midnight-to-noon shift on Friday,
James Floyd, TMI-2's supervisor of operations, decided to transfer
radioactive gases from the make-up tank to a waste gas decay tank.
Floyd knew this would release radiation because of leaks in thesystem, but he considered the transfer necessary. The pressure in
the make-up tank was so high that water that normally flowed into it
for transfer to the reactor coolant system could not enter the tank.
Floyd, without checking with other TMI and Met Ed officials, ordered
the transfer to begin at 7:10 a.m. to reduce the tank's pressure.
This controlled release allowed radioactive material to escape into
the auxiliary building and then into the air outside. Thirty-fourminutes later, Floyd requested a helicopter be sent to take radiation
The chopper reported readings of 1,000 millirems per
measurements.
hour at 7:56 a.m. and 1,200 millirems per hour at 8:01 a.m., 130 feetabove the TMI-2 vent stack.81/

11 6

ACCOUNT OF THE ACCIDENT

A helicopter taking air samples over the containment building.

11 7

ACCOUNT OF THE ACCIDENT-0-0-0At NRC headquarters, Lake Barrett, a section leader in theenvironmental evaluation branch, was concerned about the waste gas
decay tank level. The previous evening, he had helped calculate "ahypothetical release rate" for the radiation that would escape if
the tank's relief valves opened. Shortly before 9:00 a.m., Barrett
was told of a report from Three Mile Island that the waste gas decay
tanks had filled. He was asked to brief senior NRC staff officials
on the significance of this. The group included Lee Gossick, executive
director for operations; John Davis, then acting director of Inspection
and Enforcement; Harold Denton, director of Nuclear Reactor Regulation;
Victor Stello, Jr., then director of the Office of Operating Reactors;
and Harold Collins, assistant director for emergency preparedness in
the Office of State Programs. During the briefing, Barrett was
asked what the release rate would mean in terms of an off-site dose.
He did a quick calculation and came up with a figure: 1,200 millirems
per hour at ground level. Almost at that moment, someone in theroom reported a reading of 1,200 millirems per hour had been detectedat Three Mile Island. By coincidence, the reading from TMI was
identical to the number calculated by Barrett. "It was the exact
same number, and it was within maybe 10 or 15 seconds from my first
1,200 millirems per hour prediction," Barrett told the Commission.82/
The result was instant concern among the NRC officials; "anatmosphere of significant apprehension," as Collins described it inCommunications between the NRC headquarters andhis testimony.
Three Mile Island had been less than satisfactory from the beginning.
"I think there was uncertainty in the operations center as to precisely
what was going on at the facility and the question was being raisedin the minds of many as to whether or not those people up there
would do the right thing at the right time, if it had to be done,"
NRC officials proceeded without confirming the
Collins testified.
reading and without knowing whether the 1,200 millirem per hourreading was on- or off-site, whether it was taken at ground level orfrom a helicopter, or what its source was. They would later learn
that the radiation released did not come from the waste gas decay
tanks. The report that these tanks had filled was in error.83/
After some discussion, Harold Denton directed Collins to notify
Pennsylvania authorities that senior NRC officials recommended theGovernor order an evacuation. Collins telephoned Oran Henderson,
director of the Pennsylvania Emergency Management Agency, and,apparently selecting the distance on his own, recommended an evacuationof people as far as 10 miles downwind from Three Mile Island.
Henderson telephoned Lieutenant Governor Scranton, who promised tocall the Governor.
A Henderson aide also notified Thomas Gerusky,
director of the Bureau of Radiation Protection, of the evacuation
Gerusky knew of the 1,200 millirem reading. A
recommendation.
telephone call to an NRC official at the plant reinforced Gerusky's
belief that an evacuation was unnecessary. He tried to telephone
Governor Thornburgh, found the lines busy, and went to the Governor's
office to argue personally against an evacuation.84/
11 8

ACCOUNT OF THE ACCIDENT
Kevin Molloy, director of emergency preparedness for Dauphin
County, had received a call from Met Ed's James Floyd at 8:34 a.m.,alerting him to the radiation release. Twenty minutes later, thePennsylvania Emergency Management Agency notified Molloy of an
on-site emergency and an increase in radiation, but Molloy was toldthat no evacuation was needed. Then at 9:25 a.m., Henderson called
Molloy and told him to expect an official evacuation order in 5
minutes; the emergency preparedness offices in York and Lancastercounties received similar alerts.
Molloy began his preparations.
He notified all fire departments within 10 miles of the stricken
plant, and broadcast a warning over radio station WHP that anevacuation might be called.85/
At Three Mile Island, NRC's Charles Gallina was confronted by avisibly upset Met Ed employee shortly after Molloy's broadcast. "As
the best I can remember, he said, 'What the hell are you fellows
doing? My wife just heard the NRC recommended evacuation,"' Gallina
told the Commission.
Gallina checked radiation readings on- andoff-site and talked with an NRC reactor inspector, who said "things
were getting better." Then Gallina telephoned NRC officials at
Region I and at Bethesda headquarters in an attempt "to call backthat evacuation notice."86/
Shortly after 10:00 a.m., Governor Thornburgh talked by telephonewith Joseph Hendrie.
The NRC chairman assured the Governor that noevacuation was needed.
Still, Hendrie had a suggestion: thatThornburgh urge everyone within 5 miles downwind of the plant tostay indoors for the next half-hour. The Governor agreed and laterthat morning issued an advisory that all persons within 10 miles ofthe plant stay inside. During this conversation, Thornburgh asked
Hendrie to send a single expert to Three Mile Island upon whom theGovernor could rely for technical information and advice.87/
About an hour later, Thornburgh received a telephone call fromPresident Carter, who had just talked with Hendrie. The President
said that he would send the expert the Governor wanted. That expert
would be Harold Denton. The President also promised that a special
communications system would be set up to link Three Mile Island, theGovernor's office, the White House, and the NRC.88/
Thornburgh convened a meeting of key aides to discuss conditionsat Three Mile Island. During this meeting, at about 11:40 a.m., Hendrie
again called the Governor. As Gerusky recalls the conversation thattook place over a speaker phone, the NRC chairman apologized for the
NRC staff error in recommending evacuation. Just before the call,
Emmett Welch, an aide to Gordon MacLeod, had renewed the Secretaryof Health's recommendation that pregnant women and children underage 2 be evacuated. Thornburgh told Hendrie of this. Gerusky
recalls this response from Hendrie: "If my wife were pregnant and I
had small children in the area, I would get them out because we
don't know what is going to happen." 89 / After the call, Thornburgh
decided to recommend that pregnant women and preschool children
leave the region within a 5-mile radius of Three Mile Island and to
close all schools within that area. He issued his advisory shortly
after 12:30 p.m.

11 9

ACCOUNT OF THE ACCIDENT
Thornburgh was conscious throughout the accident that an evacuation might be necessary, and this weighed upon him. He later
shared some of his concerns in testimony before the Commission:
There are known risks, I was told, in an evacuation. The
movement of elderly persons, people in intensive care units,
babies in incubators, the simple traffic on the highways that
results from even the best of an orderly evacuation, are going
to exert a toll in lives and injuries. Moreover, this type ofevacuation had never been carried out before on the face of
this earth, and it is an evacuation that was quite different
in kind and quality than one undertaken in time of flood or
hurricane or tornado. . . . When you talk about evacuating
people within a 5-mile radius of the site of a nuclear reactor,
you must recognize that that will have 10-mile consequences,
20-mile consequences, 100-mile consequences, as we heard
during the course of this event. This is to say, it is an
event that people are not able to see, to hear, to taste, tosmell. . . .90/
-0-0-0Relations between reporters and Met Ed officials had deteriorated
Many reporters suspected the company of providing
over several days.
them with erroneous information at best, or of outright lying. WhenJohn Herbein arrived at 11:00 a.m. Friday to brief reporters gatheredat the American Legion Hall in Middletown, the situation worsened.
The press corps knew that the radioactivity released earlier had
been reported at 1,200 millirems per hour; Herbein did not. He
opened his remarks by stating that the release had been measured ataround 300 to 350 millirems per hour by an aircraft flying over the
The question-and-answer period that followed focused on the
Island.
radiation reading -- "I hadn't heard the number 1,200," Herbein
protested during the news conference -- whether the release wascontrolled or uncontrolled, and the previous dumping of radioactive
wastewater. At one point Herbein said, "I don't know why we need totell you each and every thing that we do specifically. . . . "91/It was that remark that essentially eliminated any credibility
Herbein and Met Ed had left with the press.92/
The next day, Jack Watson, a senior White House aide, would
telephone Herman Dieckamp, president of Met Ed's parent company, toexpress his concern that the many conflicting statements about TMI-2
reported by the news media were increasing public anxiety. Watson
would suggest that Denton alone brief reporters on the technicalaspects of the accident and Dieckamp would agree.93/-0-0-0The radiation release, Molloy's announcement of a probableevacuation, and finally the Governor's advisory brought concern andeven fear to many residents. Some people had already left, quietly
evacuating on their own; others now departed. "On March 29 of thisyear, my wife and I joyously brought home our second daughter fromthe hospital; she was just 6 days old," V.T. Smith told the Commission.
12 0

ACCOUNT OF THE ACCIDENT

Governor Richard Thornburgh testifying before the Commission.

12 1

ACCOUNT OF THE ACCIDENT

Man of the TMI area showing 5-. 10-, and 20-mile evacuation zones.

ACCOUNT OF THE ACCIDENT"On the morning of the 30th, all hell broke loose and we left for
Delaware to stay with relatives." 94 / By Saturday evening, a Goldsboro
councilman estimated 90 percent of his community's residents had
left.95/
Schools closed after the Governor's advisory. Pennsylvania
State University called off classes for a week at its Middletown
campus.
Friday afternoon, " . . . still having heard nothing fromThree Mile Island," Harrisburg Mayor Paul Doutrich drove with his
deputy public works director to the TMI Observation Center overlooking
There they talked for an hour with Met Ed
the nuclear facility.
President Creitz and Vice President Herbein. "Oddly enough, one of
the things that impressed me the most and gave me the most feelingof confidence that things were all right was that everybody in thatarea, all the employees, the president and so forth, were walking
around in their shirt sleeves, bare-headed," Doutrich told theCommission.
"I saw not one indication of nuclear protection."96/Friday, Saturday, and Sunday were hectic days in the emergency
preparedness offices of the counties close to Three Mile Island.
Officials labored first to prepare 10-mile evacuation plans and thenones covering areas out to 20 miles from the plant. The Pennsylvania
Emergency Management Agency recommended Friday morning that 10-mile
The three counties closest to the nuclear plant
plans be readied.
already had plans to evacuate their residents -- a total of about
25,000 living within 5 miles of the Island. A 10-mile evacuation
had never been contemplated. For Kevin Molloy in Dauphin County,
extending the evacuation zone meant the involvement of several hospitals -- something he had not confronted earlier. There were no
hospitals within 5 miles. Late Friday night, PEMA told county
officials to develop 20-mile plans. Suddenly, six counties wereinvolved in planning for the evacuation of 650,000 people, 13 hospitals, and a prison.97/
Friday was also the day the nuclear industry became deeply involved in the accident. After the radiation release that morning,
GPU President Dieckamp set about assembling an industry team toadvise him in managing the emergency. Dieckamp and an aide talked
with industry leaders around the country, outlining the skills andknowledge needed at TMI-2. By late Saturday afternoon, the firstmembers of the Industry Advisory Group had arrived. They met with
Dieckamp, identified the tasks that needed immediate attention, anddecided who would work on each.98/-0-0-0Harold Denton arrived on site about 2:00 p.m. Friday, bringing
with him a cadre of a dozen or so experts from NRC headquarters.
Earlier in the day, NRC had learned of the hydrogen burn or explosionthat flashed through the containment building Wednesday afternoon.
The NRC staff already knew that some form of gas bubble existed
within the reactor system. Now it became obvious that the bubble,
an estimated 1,000 cubic feet of gases, contained hydrogen. And as
Denton would later recall in his deposition, the question arose
whether there was a potential for a hydrogen explosion. Throughout

12 3

ACCOUNT OF THE ACCIDENT
Friday, Denton operated on estimates provided him before he left
Bethesda, which indicated that the bubble could not self-ignite for
5 to 8 days. Denton focused his immediate attention on finding ways
to eliminate the bubble.99/
At about 8:30 p.m. Friday, Denton briefed Governor Thornburgh
in person for the first time. Fuel damage was extensive; the bubble
posed a problem in cooling the core; no immediate evacuation was
Then the two men held their first jointnecessary, Denton said.
The Governor reiterated that no evacuation waspress conference.
needed, lifted his advisory that people living within 10 miles ofThree Mile Island stay indoors, but continued his recommendationthat pregnant women and preschool children remain more than 5 miles
from the plant.100/-0-0-0Shortly after 4:00 p.m., Jack Watson, President Carter's assistantfor intergovernmental affairs, called Jay Waldman, Governor Thornburgh's
The two disagree about the substance of that
executive assistant.
In an interview with the Commission staff, Waldman saidcall.
Watson asked that the Governor not request President Carter todeclare a state of emergency or disaster:He said that it was their belief that that would generate
unnecessary panic, that the mere statement that the President
has declared this area an emergency and disaster area would
trigger a substantial panic; and he assured me that we were
getting every type and level of federal assistance that wewould get if there had been a declaration. I told him that I
would have to have his word on that, an absolute assurance,
and that if that were true, I would go to the Governor withhis request that we not formally ask for a declaration.l01/
Watson and his assistant, Eugene Eidenberg, both said in their
Commission depositions that the White House never asked Governor
Thornburgh not to request such a declaration. 102 / Whatever was saidin that Friday conversation, the Governor made no request to the
President for an emergency declaration. State officials later
expressed satisfaction with the assistance provided by the federal
government during the accident and immediately after. They wereless satisfied, however, in August with the degree of assistance andcooperation they were receiving from federal agencies.103/-0-0-0Officials of the U.S. Department of Health, Education, andWelfare (HEW) had become concerned about the possible release ofradioactive iodine at Three Mile Island and began Friday to searchfor potassium iodide -- a drug capable of preventing radioactive
iodine from lodging in the thyroid. The thyroid absorbs potassium
iodide to a level where the gland can hold no more. Thus, if aperson is exposed to radioactive iodine after receiving a sufficientquantity of potassium iodide, the thyroid is saturated and cannot

12 4

ACCOUNT OF THE ACCIDENT
absorb the additional iodine with its potentially damaging radiation.
At the time of the TMI-2 accident, however, no pharmaceutical orchemical company was marketing medical-grade potassium iodide in thequantities needed.104/
Saturday morning, shortly after 3:00 a.m., the Mallinckrodt
Chemical Company agreed to provide HEW with approximately a quarter
million one-ounce bottles of the drug. Mallinckrodt in St. Louis,
working with Parke-Davis in Detroit and a bottle-dropper manufacturer
in New Jersey, began an around-the-clock effort. The first shipmentof potassium iodide reached Harrisburg about 1:30 a.m. Sunday. By
the time the last shipment arrived on Wednesday, April 4, the supply
totalled 237,013 bottles.105/

12 5

ACCOUNT OF THE ACCIDENTSATURDAY, MARCH 31
The great concern about a potential hydrogen explosion inside
the TMI-2 reactor came with the weekend. That it was a groundlessfear, an unfortunate error, never penetrated the public consciousness
afterward, partly because the NRC made no effort to inform thepublic it had erred.106/
Around 9:30 p.m. Friday night, the NRC chairman asked Roger Mattson
to explore the rate at which oxygen was being generated inside the
TMI-2 reactor system and the risk of a hydrogen explosion. "He said
he had done calculations," Mattson said in his deposition. "He wasconcerned with the answers." 107 / Mattson is director of the Divisionof Systems Safety within the Office of Nuclear Reactor Regulation(NRR), which is headed by Denton, and had spent part of Thursday andFriday working on how to remove a gas bubble from the reactor.
Following Denton's departure for TMI, Mattson served variously as
NRR's representative or deputy representative at the Incident Response
Center.
Hydrogen had been produced in the reactor as a result of ahigh-temperature reaction that occurred between hot steam and thezirconium cladding of the fuel rods. For this hydrogen to explodeor burn -- a less dangerous possibility -- enough oxygen would haveto enter the system to form an explosive mixture. There were fears
this would happen as the result of radiolysis. In this process,radiation breaks apart water molecules, which contain hydrogen andoxygen.
Two NRC teams worked throughout the weekend on the problem, andboth sought help from laboratories and scientists outside the NRC.
One group addressed the rate at which radiolysis would generate
oxygen at TMI-2. The second analyzed the potential for hydrogen
Robert Budnitz of the NRC also asked experts about
combustion.
possible chemicals that might remove the hydrogen.
At noon, Hendrie talked by telephone with Denton and expressed
his concern that oxygen freed by radiolysis was building up in the
Earlier, Hendrie had told Victor Stello, Jr., Denton'sreactor.
second-in-command at TMI, the same thing. The NRC chairman told
12 6

ACCOUNT OF THE ACCIDENT

NRC Chairman Joseph Hendrie testifying at a Commission hearing.

12 7

ACCOUNT OF THE ACCIDENT

Harold Denton, director of NRC's Office of Nuclear Reactor Regulation,
and Governor Thornburgh at a March 31 news conference in Harrisburg.

12 8

ACCOUNT OF THE ACCIDENT
Denton that Governor Thornburgh should be made aware of the potential
danger. Denton promised to speak with Thornburgh.
Shortly after 1:00 p.m., Mattson got some preliminary answers
regarding the potential for a hydrogen explosion.
An hour later,
Mattson got more replies. "I had an estimate there was oxygen being
generated, from four independent sources, all with known credentials
in this field," he said in his deposition. "The estimate of how
much oxygen varied, but all estimates said there was considerable
time, a matter of several days, before there was a potential combustible
mixture in the reactor coolant system."108/
At a Commission hearing, Mattson later admitted in response toquestions from Commissioner Pigford that the NRC could have determinedfrom the information available at that time that no excess oxygen
was being generated and there was no real danger of explosion.109/
But when Mattson met with the NRC commissioners at 3:27 p.m. on
Saturday, "the bottom line of that conversation . . . was there wereseveral days required to reach the flammability limit, although
there was oxygen being generated," Mattson recalled in his deposition.
"And I expressed confidence that we were not underestimating thereactor coolant system explosion potential; that is, the estimate of
2 to 3 days before reaching the flammability limit was a conservative
estimate."
By Saturday night, however, Mattson would be told by his
consultants that their calculations indicated that the oxygen percentageof the bubble was on the threshold of the flammability limit.110/
Around 6:45 p.m., Mattson talked with Vincent Noonan, the man
within NRC most knowledgeable about what might result from an explosion inside a reactor. One NRC consultant had predicted that ahydrogen blast would produce pressures of 20,000 pounds per squareinch within the TMI-2 reactor. B&W, designer of the reactor, however,had considered the dampening effects of water vapor on an explosion
and those of an enriched hydrogen environment and calculated a totalpressure of 3,000 to 4,000 psi. That was encouraging. Previous
analyses indicated the reactor coolant system of a TMI-2 reactor
could withstand blast pressures of that magnitude.
Late Saturday evening, James Taylor of B&W reiterated another
B&W engineer's conclusion first relayed to the NRC Thursday night -that no excess oxygen was being generated. That information, Mattson
stated in his deposition, never reached him.lll/
Saturday at 2:45 p.m., Hendrie met with reporters in Bethesda.
He said then that a precautionary evacuation out to 10 or 20 miles
from the Island might be necessary if engineers attempted to force
the bubble out of the reactor. NRC had concluded such an attempt
might cause further damage to the core, Hendrie said, and it mighttouch off an explosion of the bubble.
Stan Benjamin, a reporter with the Washington bureau of the
Associated Press, followed up Hendrie's press conference by interviewing two NRC officials: Edson Case, Denton's deputy in the
Office of Nuclear Reactor Regulation, and Frank Ingram, a public
information spokesman.
From them, and an NRC source he refused toname, Benjamin learned of the concern within the Incident Response

129

ACCOUNT OF THE ACCIDENT
Center that the bubble could become a potentially explosive mixture
within a matter of days, perhaps as few as two. Benjamin checked
his story with Case and Ingram, reading much of it to them word byword, before releasing the article. Case and Ingram agreed it was
accurate. The report -- first transmitted as an editor's note at
8:23 p.m. -- was the first notice to the public that some NRC officials
feared the bubble might possibly explode spontaneously.112/
Denton had been briefed throughout Saturday afternoon andevening by Hendrie and NRC officials in Bethesda on the oxygen
estimates and the potential for a burn or explosion. But he learnedof the AP story only a short time before he joined Governor Thornburghand Lieutenant Governor Scranton for a late evening press conferencein Harrisburg. The Governor assured reporters that "there is no
imminent catastrophic event foreseeable at the Three Mile Island
facility." Denton, too, said: "There is not a combustible mixture
in the containment or in the reactor vessel. And there is no near-term
danger at all." Denton also tried to deflate the impression, voiced
by several reporters, that contradictions existed between himself
and his colleagues at NRC headquarters. "No, there is no disagreement.
I guess it is the way things get presented," he said.113/
But there was disagreement, and Denton wanted it resolved.
President Carter had announced earlier in the evening he would visit
TMI the following day. Denton told Stello to explore the oxygen-hydrogenissue further with outside experts. Stello realized the concern inWashington. He had received a telephone call shortly after 9:00
p.m. from Eugene Eidenberg, a Presidential aide, inquiring about the
AP story. Stello told the White House that he did not share theconcern felt at NRC headquarters.
-0-0-0Saturday, as the NRC wrestled with managing the accident andthe envisioned danger of the hydrogen bubble, officials of the
Department of Health, Education, and Welfare struggled with theirown concerns.
That morning, senior HEW health officials gathered
and continued the previous day's discussion of the possibility of anevacuation; for the first time, they debated how large an area
should be evacuated.
But the discussions led ultimately to a
recommendation to consider immediate evacuation if the NRC could notprovide assurances that the reactor was cooling safely. Joseph Califano,HEW Secretary, summarized the group's views in a memorandum toJack Watson of the President's staff.
Later in the day, HEW health officials attended an interagency
meeting at the White House, convened by Watson, and repeated the HEW
recommendation to consider evacuation.
Richard Cotton, a key Califano
aide, raised another Califano recommendation that NRC officials
consult with HEW and Environmental Protection Agency experts regarding
the potential health effects of the efforts to control TMI-2'sreactor.
Cotton persisted after the meeting, and on Sunday andTuesday HEW officials were briefed by the NRC. These briefings,
however, were always informational; there was no NRC effort to seek
HEW's advice.114/
13 0

ACCOUNT OF THE ACCIDENTSUNDAY, APRIL 1

Throughout Saturday night and the early hours of Sunday, county
emergency preparedness offices were deluged with telephone callsfrom citizens concerned by the conflicting reports about the hydrogen
bubble.
But the flow of useful information from the state to the
local level had essentially ceased after Denton's arrival. The
Governor's office focused attention on the federal effort -- Denton
and officials from several •U . S. emergency agencies.
Oran Henderson,
director of the Pennsylvania Emergency Management Agency, was nolonger invited to the Governor's briefings and press conferences,and he did not attend after Friday night. Thus PEMA -- although it
continued to receive status reports from the Bureau of Radiation
Protection -- was isolated from information wanted at the local
level.
In Dauphin County, frustration ran high. Shortly before midnight
on Saturday, State Sen. George Gekas called the Governor in an
attempt to obtain accurate information.
Gekas was told the Governor
was too busy to talk. Then Gekas called Scranton, and got the same
response. At that point, Gekas told a Scranton aide that unless
more cooperation and information were forthcoming, Dauphin County
would order an evacuation at 9:00 a.m. Sunday. Scranton called thecounty's emergency center at 2:00 a.m. and agreed to meet officials
there later in the morning. The Lieutenant Governor arrived at
10:00 a.m., preceded by Henderson, who complained of his own inability
to obtain information. Scranton listened to Molloy and his colleagues.
"I think he was just totally shocked by what was transpiring at ourlevel; how busy we were; how much work we were doing; how complicatedit was," Molloy said in his deposition.115/-0-0-0Sunday, Mattson and several other NRC staffers met with NRC
Commissioners Hendrie, Victor Gilinsky, and Richard Kennedy. Their
purpose was to reach a judgment, based on the estimates and information
available, about the true potential for a hydrogen explosion inside
the reactor.
According to Mattson's deposition, the group agreed:

13 1

ACCOUNT OF THE ACCIDENT

President Jimmy Carter touring the TMI-2 control room with (1 tor) Harold Denton, Governor Thornburgh, and James Floyd, supervisorof TMI-2 operations, on April 1.

13 2

ACCOUNT OF THE ACCIDENT
5 percent oxygen was a realistic flammability limit, 11 percent
oxygen was a realistic detonation limit, that there could be
no spontaneous combustion below 900°F, that the oxygen production
rate was approximately one percent per day, and that thepresent oxygen concentration in the bubble was 5 percent.116/
After the meeting, Hendrie and Mattson drove to TMI to meet with
Denton.
Stello talked with Denton Sunday morning and outlined hisarguments against any danger of a hydrogen explosion inside thereactor. Pressurized water reactors, the type used at TMI-2, normallyoperate with some free hydrogen in the reactor coolant. This hydrogenjoins with the oxygen freed by radiolysis to form another watermolecule, which prevents the build-up of oxygen to a quantity thatwould allow an explosion to take place. Stello told Denton that theprocess was the same now, and there was no danger of explosion.
Hendrie and Mattson met with Denton and Stello in a hangar at
Harrisburg International Airport minutes before President Carter's
1:00 p.m. arrival.
Mattson and Stello had not talked to each othersince Friday morning.
Mattson outlined the conclusions reached at
NRC headquarters about the bubble and the reasoning behind them. In
an interview with the Commission staff, Mattson described what
happened next:
And Stello tells me I am crazy, that he doesn't believe it,that he thinks we've made an error in the rate of calculation. . . . Stello says we're nuts and poor Harold is there, he's
got to meet with the President in 5 minutes and tell it like
it is. And here he is. His two experts are not together.
One comes armed to the teeth with all these national laboratories
and Navy reactor people and high faluting PhDs around thecountry, saying this is what it is and this is his best summary.
And his other [the operating reactors division] director,
saying, "I don't believe it. I can't prove it yet, but I
don't believe it. I think it's wrong."117/Upon the President's arrival, Denton briefed the Chief Executiveon the status of the plant and the uncertainty regarding its infamous
bubble.
The President was driven to TMI, put on protective yellow
plastic shoecovers, and toured the facility with Mrs. Carter, Governor
Thornburgh, and Denton.
Stello, Hendrie, and Mattson went to thetemporary NRC offices.
During the afternoon, experts -- including
those at Westinghouse and General Electric -- were canvassed byphone.
"By three o'clock, we're convinced we've got it," Mattson
said in his interview. "It's not going to go boom."118/
NRC scientists in Bethesda eventually reached the same conclusion, but later in the day. Shortly before 4:00 p.m., NRC Commissioners Richard Kennedy, Peter Bradford, and John Ahearne met. They
expressed concern over the differing estimates presented by the NRC
staff and decided there might be a need to consider evacuation.

13 3

ACCOUNT OF THE ACCIDENT
Kennedy telephoned Hendrie at TMI and told him the three NRC
Commissioners thought Governor Thornburgh should advise a precautionary
evacuation within 2 miles of the plant, unless experts on-site had
better technical information than that available in Bethesda.119/
Hendrie assured Kennedy that the free hydrogen inside the reactor
would capture any oxygen generated and that no problem existed.
In midafternoon, new measurements showed the large bubble in
The gases still existed, but they were
the reactor was diminishing.
distributed throughout the system in smaller bubbles that madeWhy thiseliminating the predominantly hydrogen mixture easier.
occurred, no one knows. But it was not because of any intentional
manipulation by Met Ed or NRC engineers.
By late Sunday afternoon, NRC -- which was responsible for theconcern that the bubble might explode -- knew there was no danger ofa blast and that the bubble appeared to be diminishing. It was good
news, but good news unshared with the public. Throughout Sunday,
the NRC made no announcement that it had erred in its calculationsor that no threat of an explosion existed. Governor Thornburgh was
not told of the NRC miscalculation either. Nor did the NRC reveal
the bubble was disappearing that day, partly because the NRC experts
themselves were not absolutely certain.

13 4

ACCOUNT OF THE ACCIDENTMONDAY, APRIL 2

Monday morning Denton and Mattson met the press. George Troffer,a Met Ed official, had already told a reporter the bubble was
essentially gone. Denton acknowledged a "dramatic decrease inbubble size," but cautioned that more sophisticated analyses wereneeded "to be sure that the equations that are used to calculate
bubble size properly include all effects." As to the bubble's
potential for explosion, Denton told reporters "the oxygen generation
rate that I was assuming yesterday when I was reporting on thepotential detonation inside the vessel is, it now appears, to havebeen too conservative." Throughout the press conference, Denton
continued to refer to NBC's estimates as too conservative; he neverstated outright that NRC had erred in its conclusion that the bubble
was near the dangerous point.120/
According to Mattson, the tone of the press conference -- itsvagueness and imprecision -- was decided upon at a meeting of NRC
officials Monday morning.
We wanted to go slow on saying it was good news. We wanted tosay it is good news, do not panic, we think we have got it
under control, things look better, but we did not want tofirmly and finally conclude that there was no problem. We had
to save some wiggle room in order to preserve credibility.
That was our judgement."121/

13 5

ACCOUNT OF THE ACCIDENT

Harold Denton at an April 2 press conference. The bearded man
behind Denton is Roger Mattson, director of NRC's Division of Systems
Beside Denton is Joseph Fouchard, NRC's public affairs director.
Safety.

13 6

ACCOUNT OF THE ACCIDENTEPILOGUE

The accident at Three Mile Island did not end with the breaking
up of the bubble, nor did the threat to the health and safety of theworkers and the community suddenly disappear. A small bubble remained, gases still existed within TMI-2's cooling water, and thereactor itself was badly damaged. Periodic releases of low-level
radiation continued, and some feared a major release of radioactive
iodine-131 might yet occur. Schools remained closed. The Governor's
recommendation that pregnant women and preschool children stay morethan 5 miles from the plant continued.
Saturday, March 31, the Department of Health, Education, andWelfare had arranged for the rapid manufacture of nearly a quarter
million bottles of potassium iodide. 122 / That same day, thePennsylvania Bureau of Radiation Protection -- which had originallyaccepted HEW's offer to obtain the drug -- transferred responsibility
for handling the radioactive iodine blocker to the state's Department
of Health. Gordon MacLeod, who headed the health department, put the
drug shipments in a warehouse as they began arriving Sunday. During
the weekend, Thomas Gerusky, director of the Bureau of Radiation
Protection, requested that his people at TMI be issued potassium
iodide; Gerusky wanted BRP personnel to have the thyroid-blocking
agent available should a release of radioactive iodine occur.
MacLeod refused. He argued that if the public learned that any ofthe drug had been issued, a demand for its public distribution would
result.
MacLeod had the backing of the Governor's office and Harold
Denton in his decision not to issue the potassium iodide. The decision did not find agreement in Washington, however. On Monday, Jack
Watson asked HEW to prepare recommendations for the drug's distribution and use. These were developed by a group headed by Donald
Frederickson, director of the National Institutes of Health. The
recommendation included: administering potassium iodide immediately
to all workers on the Island; providing the drug to all people who
would have less than 30 minutes' warning of a radioactive iodine
release (roughly those within 10 miles of the plant); and that local
authorities assess these recommendations in light of their first-handknowledge of the situation.
13 7

ACCOUNT OF THE ACCIDENT
Governor Thornburgh received the recommendations in a WhiteHouse letter on Tuesday, although some Pennsylvania officials hadlearned of them Monday. MacLeod strongly opposed distributing the
drug to the public. Among his reasons: radioiodine levels were far
below what was indicated for protective action, and the likelihoodof a high-level release from TMI-2 was diminishing; distributing the
drug would increase public anxiety and people might take it without
being told to do so; and the possibility of adverse side-effects
presented a potential public health problem in itself. MacLeod chose
not to accept the federal recommendations. The potassium iodide
remained in a warehouse under armed guard throughout the emergency.
In midsummer, the FDA moved the drug to Little Rock, Arkansas, forstorage.
-0-0-0Tuesday, April 3, General Public Utilities, Met Ed's parent
company, established its TMI-2 recovery organization to oversee anddirect the long process of cleaning up TMI-2. Robert Arnold, a vicepresident of another subsidiary, the GPU Service Corporation, wasnamed to head the recovery operation.123/
Wednesday, April 4, schools outside the 5-mile area surrounding
TMI reopened. All curfews were lifted. But schools within 5 milesof the Island remained closed and the Governor's advisory remainedin effect for pregnant women and preschool children.
Some sense of normalcy was gradually returning to the TMI area.
Governor Thornburgh asked Denton repeatedly if the advisory could be
lifted, allowing pregnant women and preschool children to return
But the NRC wanted some specific event as a symbol to announcehome.
the crisis had ended. At first, the NRC looked to reaching "cold
shutdown" -- the point at which the temperature of TMI-2's reactor
coolant fell below the boiling point of water. When it became
obvious that cold shutdown was days away, agreement was reached
between Pennsylvania's Bureau of Radiation Protection and the NRC on
On Saturday, April 7, Kevin Molloy, at theending the advisory.
request of the Governor's office, read a press release announcing
the closing of the evacuation shelter at the Hershey Park Arena.
Not until 2 days later, however, did Governor Thornburgh officiallywithdraw the advisory.124/-0-0-0The accident at TMI did not end with cold shutdown, nor will it
end for some time. More than a million gallons of radioactive waterremain inside the containment building or stored in auxiliary building
The containment building also holds radioactive gases andtanks.
the badly damaged and highly radioactive reactor core. Radioactive
elements contaminate the walls, floors, and equipment of several
Ahead lies a decontamination effort unprecedented in thebuildings.
history of the nation's nuclear power industry -- a cleanup whose
total cost is estimated at $80 to $200 million and which will takeseveral years to complete.125/
13 8

ACCOUNT OF THE ACCIDENT

The potassium iodide supplies in a Harrisburg warehouse.

13 9

ACCOUNT OF THE ACCIDENT

TMI personnel cleaning up the contaminated auxiliary building.

14 0

ACCOUNT OF THE ACCIDENT
The initial cleanup began in April. Using a system called
EPICOR-I, Met Ed began decontaminating pre-accident water stored in
the TMI-1 auxiliary building, which contains low levels ofradioactivity (less than one microcurie per milliliter). Efforts todecontaminate the TMI-2 diesel generation building began in April
and work on the auxiliary and fuel handling buildings got under way
This involves mostly dry and wet vacuuming, mopping, andin May.
wiping of radioactive areas to remove the contamination -- a taskthat requires special clothing and respirators to protect workers.
The accident and its subsequent cleanup already have produced avariety of solid, slightly radioactive wastes, such as clothing,rags, ion-exchange resins, swipes, and contaminated air filters. To
date, 12 truckloads of these wastes have been hauled to Richland,
Washington, and buried at a commercial disposal site.
But the more difficult aspects of decontamination -- bothtechnically and politically -- lie ahead. Met Ed has asked the NRC
for permission to release the krypton-85 in the air of the containmentbuilding into the atmosphere in controlled bursts. The releases
would come over a 2-month period to ensure that off-site radiation
does not exceed the NRC's limits for routine operation of a nuclear
power plant.
Much of the contaminated water left from the accident -- some
600,000 gallons pooled in the containment building and about 90,000
gallons in the reactor coolant system -- contains high levels ofradioactivity (in excess of 100 microcuries per milliliter). Met Ed
had stored 380,000 gallons of water containing intermediate levelsof radioactivity (1 to 100 microcuries per milliliter) in several
Over the summer, the utility installed
TMI-2 auxiliary building tanks.
a system called EPICOR-II to treat this water. NRC approved its
use, provided that the resins used to remove radioactive materials
from the water were solidified before shipment from the Island to a
Met Ed began decontaminating the intermediate waterdisposal site.
in mid-October.
Until radioactive gases are removed from the containment building,no human entry into the sealed structure can be made. Meanwhile,detailed plans for entry and assessing conditions inside the building
Because no one knows the exact condition ofare being developed.
the reactor vessel or its core, no detailed plans have been made forhandling and removing its damaged core.
Thus, the accident at Three Mile Island, in a very real sense,
continues and will continue until the years-long cleanup of TMI-2 iscompleted. Workers will receive additional radiation doses until
the decontamination process is completed; five workers in lateAugust, for example, received doses in excess of the NRC's quarterly
limits for exposure to the skin or the extremities. And there still
remains some risk to the general public that released radiation
could escape from the Island.

14 1

ACCOUNT OF THE ACCIDENTFOOTNOTES

1.

For times cited in narrative, please refer to the "Catalog of
Events" compiled by the Commission's Technical Assessment Task
This unpublished document is available with the Commission's
Force.
official records in the National Archives.

2.

Commission Hearing, May 19, 1979, pp. 24, 27-28. For a discussionof the mental health effects of the TMI accident, see "Report ofthe Behavioral Effects Task Group."

3.

General Public Utilities Corporation, 1978 Annual Report. For afull discussion of the Commission's investigation of GPU and its
subsidiary, Metropolitan Edison, see "Report of the Office of ChiefCounsel on the Role of the Managing Utility and Its Suppliers."4.

See history section of "Report of the Office of Chief Counsel on
the Nuclear Regulatory Commission."5.

See "How a Nuclear Reactor Works," a lecture presented byCommissioner Theodore B. Taylor to members of the Commission,
April 26, 1979.

6.

Final Safety Analysis Report, TMI-2, Vol. 4, pp. 4.2-37, 4.3-20.
See also Taylor, supra.

7.

Final Safety Analysis Report, TMI-2, Vol. 4, pp. 4.2-4, 4.2-5,
4.3-19; figures 4.2-4, 4.3-25, 4.2-26; and Vol. 7, p. 7.8-3; figure
7.8-4.

8.

See Taylor, supra.
See also technical staff analysis report on"Alternative Event Sequences."

9.

Final Safety Analysis Report, TMI-2, Vol. 3, p. 3.8-38.

10.

See technical staff analysis reports on "Core Damage," "Chemistry,""Thermal Hydraulics," and "Alternative Event Sequences."11.

For a complete discussion of the pilot-operated relief valve, seetechnical staff analysis report on "Pilot-Operated Relief Valve
14 2

ACCOUNT OF THE ACCIDENT
Design and Performance," and section on PORV failure history in"Report of the Office of Chief Counsel on the Role of the Managing
Utility and Its Suppliers." See also discussion of "safety-related"
items in "Report of the Office of Chief Counsel on the Nuclear
Regulatory Commission."
12.

Commission Hearing, May 30, 1979, pp. 10, 115, 152-153.

13.

For a full discussion of Metropolitan Edison's and Babcock &Wilcox's treatment of problems associated with pilot-operated
relief valves, see "Report of the Office of Chief Counsel on theRole of the Managing Utility and Its Suppliers."

14.

For a discussion on operator training, see technical staff analysis
report on "Selection, Training, Qualification, and Licensing ofThree Mile Island Reactor Operating Personnel."See also
technical staff analysis report on "Technical Assessment of
Operating, Abnormal, and Emergency Procedures;" and sections on
attention to experience, TMI-2 site management, and procedures in"Report of the Office of Chief Counsel on the Role of the Managing
Utility and Its Suppliers;" and section on operator training andlicensing in "Report of the Office of Chief Counsel on the Nuclear
Regulatory Commission."

15.

Id.

16.

For a full discussion of the control room, see technical staff
analysis report on "Control Room Design and Performance." See also
"Report of the Office of Chief Counsel on the Role of the Managing
Utility and Its Suppliers" for a discussion of the TMI-2 control
room design history and design performance during the accident; and"Report of the Office of Chief Counsel on the Nuclear Regulatory
Commission" on the NRC's consideration of human factors in design
review during plant licensing.

17.

Commission Hearing, May 30, 1979, p. 168.

18.

See technical staff analysis report on "Condensate Polishing System."
See also section on attention to experience in "Report of the
Office of Chief Counsel on the Role of the Managing Utility and Its
Suppliers."

19.

For a discussion on operator training, see technical staff analysis
report on "Selection, Training, Qualification, and Licensing ofThree Mile Island Reactor Operating Personnel."See also technicalstaff analysis report on "Technical Assessment of Operating,Abnormal, and Emergency Procedures;" and sections on attention toexperience, TMI-2 site management, and procedures of "Report of the
Office of Chief Counsel on the Role of the Managing Utility and Its
Suppliers;" and section on operator training and licensing in "Reportof the Office of Chief Counsel on the Nuclear Regultory Commission."

20.

Commission Hearing, May 30, 1979, p. 168.
14 3

ACCOUNT OF THE ACCIDENT
21.

See technical staff analysis report on "Technical Assessment of
Operating, Abnormal, and Emergency Procedures." See also discussionof pressurizer level and "going solid" in procedures section of"Report of the Office of Chief Counsel on the Role of the Managing
Utility and Its Suppliers."

22.

Commission Hearing, May 30, 1979, p. 194.

23.

Commission Hearing, May 30, 1979, pp. 114-115; Commission Hearing,
May 31, 1979, p. 40.

24.

See technical staff analysis report on "Closed Emergency Feedwater
Valves."25.

See technical staff analysis report on "Technical Assessment of
Operating, Abnormal, and Emergency Procedures." See also discussionof emergency procedures for loss of reactor coolant and for
identifying the open pilot-operated relief valve in procedures
section of "Report of the Office of Chief Counsel on the Role ofthe Managing Utility and Its Suppliers."

26.

Commission Hearing, May 30, 1979, p. 128.

27.

Commission Hearing, May 30, 1979, p. 129.

28.

See technical staff analysis report on "Technical Assessment of
Operating, Abnormal, and Emergency Procedures." See also discussionof emergency procedures for loss of reactor coolant and for
identifying the open pilot-operated relief valve in procedures
section of "Report of the Office of Chief Counsel on the Role ofthe Managing Utility and Its Suppliers."

29.

Commission Hearing, May 30, 1979, p. 146.

30.

See unpublished "Catalog of Events."

31.

Commission Hearing, May 31, 1979, p. 38.

32.

Commission Hearing, May 30, 1979, p. 187.

33.

Commission Hearing, May 30, 1979, p. 161.

34.

See technical staff analysis reports on "Core Damage," "Thermal
Hydraulics," and "Chemistry." See also section on Met Ed's
understanding of core condition on March 28 in "Report of the
Office of Chief Counsel on the Role of the Managing Utility and Its
Suppliers."

35.

Rogers deposition, pp. 84-85.

36.

Commission Hearing, May 30, 1979, pp. 119-120.

37.

See technical staff analysis reports on "Core Damage" and "Chemistry."
14 4

ACCOUNT OF THE ACCIDENT
38.

Final Safety Analysis Report, TMI-2, Vol. 13, p. 13A-3..

39.

Commission Hearing, May 31, 1979, pp. 6-7.

40.

Prepared testimony of Gary Miller, Commission Hearing, May 31,
1979:"TMI Station March 28, 1979, Incident Statement by G. P.
Miller, Station Manager," pp. 3-4.

41.

NRC Region I answering service log. For a complete discussion of
the emergency response during the TMI accident, see "Report of the
Office of Chief Counsel on Emergency Response," which is in theform of a chronology. See also "Technical Report on Emergency
Preparedness and Response." For a discussion of Met Ed's managementof the accident, see section on management approach to the emergencyof "Report of the Office of Chief Counsel on the Role of the Managing
Utility and Its Suppliers."

42.

Dornsife deposition, p. 20.

43.

Final Safety Analysis Report, TMI-2, Vol. 13, p. 13A-4.

44.

For a discussion of containment and isolation, see technical staff
analysis report on "Containment."

45.

Mattson deposition, pp. 12-14. For a complete discussion of"grandfathering" and other matters related to plant licensing, seesection on plant licensing in "Report of the Office of Chief Counsel
on the Nuclear Regulatory Commission."46.

For a complete discussion on selection of containment isolation
criteria for TMI-2, see section on containment isolation criteria
in "Report of the Office of Chief Counsel on the Role of theManaging Utility and Its Suppliers."

47.

See technical staff analysis report on "Containment."48.

Commission Hearing, May 31, 1979, p. 51.

49.

Commission staff notes of Pintek interview, pp. 1-2.

50.

For a discussion of news media coverage of the TMI accident, see"Report of the Public's Right to Information Task Force."

51.

Commission Hearing, May 19, 1979, p. 125.

52.

Commission Hearing, May 31, 1979, pp. 236-237.

53.

In addition to unpublished "Catalog of Events," please refer to"Report of the Office of Chief Counsel on Emergency Response" fortimes and dates cited.

14 5

ACCOUNT OF THE ACCIDENT
54.

Commission Hearing, May 19, 1979, p. 15.

55.

Commission Hearing, August 2, 1979, pp. 180-183.

56.

Transcript of Scranton news conference, March 28, 1979, 10:55 a.m.

57.

Id. For a discussion on radiation exposure to the public during
the accident and its potential health effects, see "Report of the
Health Physics and Dosimetry Task Group" and "Report of the
Radiation Health Effects Task Group."

58.

Commission Hearing, August 2, 1979, p. 184. See also discussion of
information sources in "Report of the Public's Right to Information
Task Force."59.

See technical staff analysis reports on "Thermal Hydraulics,""Chemistry," and "Technical Assessment of Operating, Abnormal, andEmergency Procedures." See also discussion of rapid
depressurization in emergency response section of "Report of the
Office of Chief Counsel on the Nuclear Regulatory Commission."60.

For a discussion of the radiation exposure to workers during theaccident, see "Report of the Health Physics and Dosimetry Task
Group." For a discussion on NRC requirements for Met Ed's
provisions for worker protection, see "Report of the Public Healthand Epidemiology Task Group."

61.

Commission Hearing, May 31, 1979, p. 57.

62.

Commission Hearing, May 31, 1979, p. 58.

63.

Rogers deposition, p. 114.

64.

Commission Hearing, May 31, 1979, p. 59.

65.

For a discussion on radiation exposure to the public during theaccident and its potential health effects, see "Report of the
Health Physics and Dosimetry Task Group" and "Report of the
Radiation Health Effects Task Group."

66.

Governor's log, March 28, 1979, p. 3.

67.

Transcript of Scranton news conference, March 28, 1979, 4:30 p.m.

68.

Id.

69.

Commission Hearing, May 19, 1979, pp. 37, 41.

70.

Dauphin County Office of Emergency Preparedness log, March 29,
1979.

71.

For a discussion of radiation monitoring during the accident, see"Report of the Health Physics and Dosimetry Task Group."
14 6

ACCOUNT OF THE ACCIDENT
72.

MacLeod deposition, pp. 21-26.

73.

Robbins deposition, pp. 36-37.

74.

MacLeod deposition, pp. 29-36.

75.

Reilly interview, pp. 92-94; Gallina deposition, pp. 56-57; Smithdeposition, p. 36; and Gerusky interview, pp. 24-25. See also
"Report of the Public's Right to Information Task Force."

76.

NRC telephone transcript, March 29, 1979, 02-228-CH6/KD-2-6.

77.

Pennsylvania DER news release, March 29, 1979. See also "Report of
the Public's Right to Information Task Force" and "Report of the
Office of Chief Counsel on Emergency Response."

78.

Higgins deposition, pp. 42, 45-46; Gallina deposition, p. 60;
Critchlow interview, first and second tape, pp. 15-18.

79.

Barrett deposition, pp. 39-50.

80.

Commission Hearing, August 2, 1979, pp. 316.

81.

Commission Hearing, May 31, 1979, pp. 172-181.

82.

Commission Hearing, August 2, 1979, pp. 298-299.

83.

Id., pp. 303-316.

84.

Collins deposition, pp. 70-72; Scranton interview, p. 54; Gerusky
deposition, pp. 53-54; Dornsife deposition, p. 76; NRC telephonetranscript, March 30, 1979, 03-019-CH2.20 SW-10.

85.

Molloy deposition, pp. 48-49; Commission Hearing, August 2, 1979,
pp. 10-11.

86.

Commission Hearing, May 31, 1979, pp. 257-258.

87.

Thornburgh deposition, p. 77.

88.

Commission Hearing, August 21, 1979, p. 10.

89.

Gerusky deposition, pp. 64-65, 67.

90.

Commission Hearing, August 21, 1979, p. 25.

91.

Transcript of Herbein news conference, March 30, 1979, 11:00 a.m.

92.

See "Report of the Public's Right to Information Task Force."

14 7

ACCOUNT OF THE ACCIDENT
93.

Watson deposition, pp. 73-76, 90-91.

94.

Commission Hearing, May 19, 1979, p. 221.

95.

Commission Hearing, May 19, 1979, p. 38. For a discussion of themental health effects of the TMI accident, see "Report of the
Behavioral Effects Task Group."

96.

Commission Hearing, May 19, 1979, p. 127.

97.

Henderson deposition, pp. 71-73; Commission Hearing, August 2, 1979,
For full discussion on emergency planning and response,
pp. 12-18.
see "Technical Report on Emergency Preparedness and Response,""Report of the Public Health and Epidemiology Task Group," "Report of
the Office of Chief Counsel on Emergency Preparedness," and "Reportof the Office of Chief Counsel on Emergency Response." For dates andtimes in the following section, refer to the latter report.

98.

Dieckamp deposition, pp. 129-136.

99.

Denton deposition, pp. 101-102. For a complete discussion of theevents concerning the hydrogen bubble, see "Report of the Office ofChief Counsel on Emergency Response." See also technical analysis
of hydrogen production in technical staff analysis report on"Chemistry."

100. Knouse interview, pp. 71-73; transcript of Denton-Thornburgh news
conference, March 30, 1979.
101. Waldman interview, pp. 68-69.
102. Watson deposition, pp. 52-57; Eidenberg deposition,
103. Commission Hearing, August 2, 1979, pp. 194-195.

p. 47-48.

104. For a complete recount of the potassium iodide story, see "Reportof the Public Health and Epidemiology Task Group" and "Report of
the Office of Chief Counsel on Emergency Response."105. Villforth deposition, pp. 33-35; "Chronology of Events at HEW
Regarding TMI, 3/28/79 through 4/30/79."
106. For a complete discussion of the events concerning the hydrogen
bubble, see "Report of the Office of Chief Counsel on Emergency
Response." See also technical analysis of hydrogen production intechnical staff analysis report on "Chemistry."
107. Mattson deposition, p. 184.
108. Id., p. 186.
109. Commission Hearing, August 22, 1979, pp. 294-296. See also Mattson
deposition, pp. 178-180.
14 8

ACCOUNT OF THE ACCIDENT
110. Mattson deposition, p. 179.
111. Id., pp. 190-191.
112. For a full discussion on this incident, see "Report of the Public's
Right to Information Task Force."
113. Transcript of Denton-Thornburgh news conference, March 31, 1979,
Part 1, p. 3.
114. For a more detailed discussion of HEW's activities during theaccident, see "Report of the Office of Chief Counsel on Emergency
Response" and "Report of the Public Health and Epidemiology Task
Group."
115. Molloy deposition, pp. 81-100. See also Commission Hearing,
August 2, 1979, p. 16.
116. Mattson deposition, p. 192.
117. Mattson interview, cassette 16, parts 5 and 6, pp. 34-35.
118. Id., cassette 17, parts 7 and 8, p. 4.
119. For a discussion on the NRC commissioners and their role in the
management of the agency and during the emergency, see "Report of
the Office of Chief Counsel on the Nuclear Regulatory Commission."
120. Transcript of Denton news conference, April 2, 1979. For a
discussion of NRC public statements on the hydrogen bubble problems,see "Report of the Public's Right to Information Task Force."
121. Mattson interview, cassette 17, parts 7 and 8, p. 7. See also
"Report of the Public's Right to Information Task Force."
122. For a complete recount of the potassium iodide story, see "Reportof the Public Health and Epidemiology Task Group" and "Report of
the Office of Chief Counsel on Emergency Response."
123. For discussion of Met Ed's recovery efforts, see section on TMI-2
recovery program in "Report of the Office of Chief Counsel on theRole of the Managing Utility and Its Suppliers" and technical staff
analysis report on "Recovery."124. Molloy deposition, pp. 115-117. See also "Report of the Office ofChief Counsel on Emergency Response" and "Technical Staff Report on
Emergency Preparedness and Response."
125. For a discussion of TMI-2's recovery program, see technical staff
analysis report on "Recovery" and the TMI-2 recovery program sectionof "Report of the' Office of Chief Counsel on the Role of the Managing
Utility and Its Suppliers."

14 9

APPENDICESEXECUTIVE ORDER 12130
PRESIDENT'S COMMISSION ON THE ACCIDENT AT
THREE MILE ISLAND
By the authority vested in me as President by the Constitution of
the United States of America, and in order to provide, in accordancewith the provisions of the Federal Advisory Committee Act (5 U.S.C.
App. 1), an independent forum to investigate and explain the recent
accident at the nuclear power facility at Three Mile Island in
Pennsylvania, it is hearby ordered as follows:
1-1.

Establishment.

1-101. There is established the President's Commission on the
Accident at Three Mile Island.
1-102. The membership of the Commission shall be composed of not
more than twelve persons appointed by the President from among citizens
who are not full time officers or employees in the Executive Branch.
The President shall designate a Chairman from among the members of theCommission.
1-2.

Functions.

The Commission shall conduct a comprehensive study and1-201.
investigation of the recent accident involving the nuclear power facility
on Three Mile Island in Pennsylvania. The study and investigation shall
include:(a)a technical assessment of the events and their causes;(b)

an analysis of the role of the managing utility;(c) an assessment of the emergency preparedness and response of
the Nuclear Regulatory Commission and other Federal, state and local
authorities;

15 1

EXECUTIVE ORDER

an evaluation of the Nuclear Regulatory Commission's(d)licensing, inspection, operation and enforcement procedures as applied
to this facility;(e) an assessment of how the public's right to information
concerning the events at Three Mile Island was served and of the steps
which should be taken during similar emergencies to provide the publicwith accurate, comprehensible and timely information; and(f) appropriate recommendations based upon the Commission's
findings.
1-202. The Commission shall prepare and transmit to the President
and to the Secretaries of Energy and Health, Education and Welfare a
final report of its findings and recommendations.
1-3.

Administration.

1-301. The Chairman of the Commission is authorized to appoint andfix the compensation of a staff of such persons as may be necessary todischarge the Commission's responsibilities, subject to the applicableprovisions of the Federal Advisory Committee Act and Title 5 of theUnited States Code.
To the extent authorized by law and requested by the
1-302.
Chairman of the Commission, the General Services Administration shallprovide the Commission with necessary administrative services,
facilities, and support on a reimbursable basis.
1-303. The Department of Energy and the Department of Health,
Education, and Welfare shall, to the extent permitted by law and subject
to the availability of funds, provide the Commission with such
facilities, support, funds and services, including staff, as may benecessary for the effective performances of the Commission's functions.
1-304. The Commission may request any Executive agency to furnish
such information, advice or assistance as it deems necessary to carryout its functions. Each such agency is directed, to the extent
permitted by law, to furnish such information, advice or assistance uponrequest by the Chairman of the Commission.
1-305. Each member of the Commission may receive compensation at
the maximum rate now or hereafter prescribed by law for each day suchmember is engaged in the work of the Commission. Each member may also
receive travel expenses, including per diem in lieu of subsistence(5 U.S.C. 5702 and 5703).
1-306. The functions of the President under the Federal Advisory
Committee Act which are applicable to the Commission, except that ofreporting annually to the Congress, shall be performed by the
Administrator of General Services.

15 2

EXECUTIVE ORDER
1-4. Final Report and Termination.
1-401. The final report required by Section 1-202 of this Ordershall be transmitted not later than six months from the date of theCommission's first meeting.
1-402. The Commission shall terminate two months after thetransmittal of its final report.

/s/

Jimmy Carter

THE WHITE HOUSE
April 11, 1979

15 3

COMMISSIONOPERATIONS & METH ODOLOGYThis appendix will appear in thepermanent edition of the report.

15 5

COMMISSIONERS' BIOGRAPHIES
Babbitt, Bruce.
Governor of Arizona, 1978- . Born: June 27,
1938, Los Angeles, Calif. Education: Notre Dame University (BA,1960); University of Newcastle, England (MS, 1963); Harvard Law
School (LLB, 1965).
Experience:
special assistant to director,
VISTA, 1966-67; attorney, Brown & Bain, Phoenix, Ariz., 1967-74;
attorney general of Arizona, 1974-78.
Honors & Awards: Marshall
Scholar, 1960-62; Thomas Jefferson Award, 1979, Society of Professional
Grand Canyon:
An
Journalists-Sigma Delta Chi.
Publications:
Anthology (1978); Color and Light: The Southwest Canvases of Louis Akin
National Governors' Association (chairman,(1974). Memberships:
Subcommittee on Public Protection); Four Corners Regional Commission;
Activities:
former member, National Association of Attorneys General.
Advisory Commission on Intergovernmental Relations; chairman, Southwest
Border Regional Commission; Advisory Committee, Kennedy School ofGovernment, Harvard University.
Haggerty, Patrick Eugene. General Director and Honorary Chairman,
Texas Instruments, Inc., Dallas, Tex., 1976- . Born: March 17,
1914, Harvey, N.D. Education: Marquette University (BS, 1936).
Experience:
Badger Carton Co., Milwaukee, Wis., 1935-42: production
manager, 1935-39, assistant general manager, 1939-42; lieutenant,
U.S. Naval Reserve at Bureau of Aeronautics, U.S. Dept. of the Navy,general manager, Laboratory
1942-45; Texas Instruments, Inc., 1945-76:
and Manufacturing Division, 1945-51, executive vice president anddirector, 1951-58, president, 1958-66, chairman, 1966-76, retired,1976. Honors & Awards: Medal of Honor, 1967, Electronic Industries
Association; Founders Award, 1968, Institute of Electrical andElectronics Engineers; Industrial Research Institute Medalist, 1969;
John Fritz Medalist, 1971; Alumnus of the Year, 1972, Marquette
University; Wema Medal of Achievement, 1972; Henry Laurence Gantt
Medal, 1975; honorary doctorates from: St. Mary's University, 1959,
Marquette University, 1960, Polytechnic Institute of Brooklyn, 1962,
University of Dallas, 1964, North Dakota State University, 1967,
Catholic University, 1971, Rensselaer Polytechnic Institute, 1972,
Management Philosophies
University of Notre Dame, 1974. Publications:(1965),
The
Productive
Societyand Practices of Texas Instruments
Rockefeller
University(chairman,
Boardof(1973). Memberships:
Trustees); University of Dallas (Board of Trustees and Executive

15 7

COMMISSIONERS' BIOGRAPHIESCommittee); Institute of Electrical and Electronics Engineers (Fellow);
National Academy of Engineering (elected, 1965); American Association
for the Advancement of Science (Fellow); National Security Industrial
Association (life member and former vice chairman, Board of Trustees);
Texas Academy of Science (life member); The Business Council.
Activities: vice chairman, Defense Science Board, 1965-67; National
Commission on Technology, Automation, and Economic Progress, 1968;
Presidential Science Advisory Committee, 1970-71; chairman, National
Council on Educational Research, 1973-74; Executive Committee,
Tri-Lateral Commission, 1973-76; Board of Governors, U.S. Postal
Service, 1972-73.

President, Dartmouth College, Hanover, N.H., 1970- .
Kemeny, John G.
Born: May 31, 1926, Budapest, Hungary; came to U.S. 1940; naturalized
U.S. citizen, 1945. Education: Princeton University (BA, 1947;
assistant, Theoretical Division, Manhattan
PhD ) 1949). Experience:
Project, U.S. Dept. of the Army, Los Alamos Scientific Laboratory,
N. Mex., 1945-46; research assistant to Albert Einstein, Institute
Fine
for Advanced Study, 1948-49; Princeton University, 1949-53:
Instructor in Mathematics, 1949-51, assistant professor of philosophy,
professor of mathematics,
1951-53; Dartmouth College, 1953-70:
1953-70, chairman of Mathematics Department, 1955-67, Albert Bradley
Honors & Awards: Priestley
Third Century Professor, 1969-70.
Middlebury College, 1965,
Award, 1976; honorary doctorates from:
Columbia University, 1971, Princeton University, 1971, University of
New Hampshire, 1972, Boston College, 1973, University of Pennsylvania,
1975, Colby College, 1976, Bard College, 1978, Lafayette College,
A Philosopher Looks at Science (1959),
1978.
Publications:
Man and the Computer (1972), Random Essays, numerous articles;
co-author:
Basic Programming (1968), Denumerable Markov Chains(1966), Finite Mathematics with Business Applications (1962), Finite
Markov Chains (1960), Mathematical Models in the Social Sciences(1962), Finite Mathematical Structures (1958), Introduction to Finite
Mathematics (1957); contributor, Encyclopaedia Britannica; associate
editor, Journal of Mathematical Analysis and Applications, 1959-70.
Phi Beta Kappa; Association for Symbolic Logic
Memberships:(consulting editor, 1950-59); Mathematical Association of America(chairman, New England Section, 1959-60; Board of Governors, 1960-63;
chairman, Panel on Teacher Training, 1961-63; chairman, Panel on
Biological and Social Sciences, 1963-64); American MathematicalSociety; American Philosophical Association; American Academy ofArts and Sciences; Sigma Xi (national lecturer, 1967); National
Council of Teachers of Mathematics; American Association for the
consultant, Rand Corp., 1953-70;
Advancement of Science.
Activities:
consultant, Educational Research Council of Greater Cleveland,
1959-70; chairman, U.S. Commission on Mathematics Instruction,
vice chairman, Advisory
1958-60; National Research Council, 1963-66;
Committee on Computing, National Science Foundation, 1968-69; delivered
Vanuxem Lectures, Princeton University, 1974; National Commission on
Libraries and Information Science, 1971-73; Advisory Committee to
Regional Director, U.S. Dept. of Health, Education, and Welfare,
1971-73; trustee, Foundation Center, 1970-76; trustee, Carnegie
Foundation for Advancement of Teaching, 1972-78; director, Council
for Financial Aid to Education, 1976-79; director, Honeywell, Inc.,
1978-79.
15 8

COMMISSIONERS' BIOGRAPHIES
Lewis, Carolyn Diana.
Associate Professor and Coordinator of the
Broadcast Division, Columbia University Graduate School of Journalism,
New York, N.Y., 1978- . Born: Sept. 8, 1931, New York, N.Y.
Education: University of Arizona (BA, 1951); University of Oslo,
Norway (1951); University of Sydney, Australia (1956-58). Experience:
reporter, United Press International, Sydney, 1954-56; radio news
commentator, Macquarie Network, Australia, 1958-65; television news
commentator, ATN, Sydney, 1958-65; reporter and columnist, Daily Mirror,
Sydney, 1959-65; reporter, Washington Post, 1965-68; Capitol Hillcorrespondent, WTOP-TV and radio, 1968-74; moderator, "Meeting of
the Minds," WNBC, 1966-68; Capitol Hill correspondent, TelevisionNews, Inc., 1974; correspondent, impeachment hearings, PBS (National
Public Affairs Center for Television), 1974-75; associate professor
Honors & Awards: Gavelof journalism, Boston University, 1975-78.
Award, American Bar Association.
Publications:
regular contributor,
Op-Ed, The New York Times; Washington Post; Reader's Digest; TV Guide;
chapter in 1979 Dupont-Columbia University Survey of Broadcast
Journalism. Memberships:
Phi Kappa Phi; Delta Sigma Rho.
Marks, Paul Alan. Vice President for Health Sciences, 1973- ,Frode Jensen Professor of Medicine, 1974- ; Professor of Human
Genetics and Development, 1969- , Director, Cancer Center, 1973- ,Columbia University, New York, N.Y. Born: Aug. 16, 1926, New York,N.Y.
Education:
Columbia College, Columbia University (AB, 1945);
College of Physicians and Surgeons, Columbia University (MD, 1949).
Experience:senior investigator, National Institutes of Health,1953-55; Columbia University, 1952- : Fellow, College of Physiciansand Surgeons, 1952-53, instructor in medicine, 1955-56, associate in
medicine, 1956-57, assistant professor of medicine, 1957-61, associate
professor of medicine, 1961-67, professor of medicine, 1967-74,
chairman, Dept. of Human Genetics and Development, 1969-70, dean,
Faculty of Medicine, 1970-73; visiting attending physician, Francis
Delafield Hospital, 1959-75; visiting scientist, Laboratory of
Cellular Biochemistry, Pasteur Institute, Paris, France, 1961-62;
Presbyterian Hospital, 1962- : associate attending physician,
1962-67, attending physician, 1967- . Honors & Awards: Phi Beta
Kappa; Columbia University:
Janeway Prize, 1949, Joseph Mather
Smith Prize, 1959, Stevens Triennial Prize, 1960, Bicentennial
Medal, 1968; Swiss-American Foundation Award in Medical Research,
1965; Fellow, American Academy of Arts and Sciences, 1972; Instituteof Medicine, National Academy of Sciences, 1972. Publications:numerous articles; Editorial Board, 1964-71, associate editor,
1976-77, editor-in-chief, 1978- , Blood, Journal of the American
Society of Hematology; editor, 1967-71, associate editor, 1971-72,
Journal of Clinical Investigation; consulting editor, Blood Cells,
1974- . Memberships: American Association for the Advancement of
Science; American Association for Cancer Research; American Collegeof Physicians; American Society of Hematology (chairman, Committee
on Scientific Affairs, 1970, chairman, Publications Committee,
1973-74); American Society of Human Genetics (Program Committee,1963); Association of American Physicians; American Society for
Clinical Investigation (president, 1971-72); National Academy of
Sciences (elected, 1973).
Activities: Advisory Panel, National
Science Foundation, 1964-67; Organizing Committee, International
School for Developmental Biology, NATO, 1971-72; Delos Conferences,

15 9

COMMISSIONERS' BIOGRAPHIESAthens, Greece, 1971-73; chairman, Hematology Training Grants Committee,
National Institutes of Health, 1971-73; chairman, Executive Committee,
Division of Medical Sciences, National Research Council, National
Academy of Sciences, 1973-76; Founding Committee, Radiation Effects
Research Foundation, Japan, 1975-77; President's Panel on Biomedical
Research, 1975-76; President's Cancer Panel, 1976- ; trustee,
St. Luke's Hospital Center, 1970- ; trustee, Roosevelt Hospital,
1970- ; trustee, Presbyterian Hospital, 1972- ; Board of Directors,
Keystone Life Sciences Center, Colo., 1976- ; director, Charles H.
Revson Foundation, Inc., 1976- ; Board of Trustees, Metpath Institutefor Medical Education, 1977- ; director, Dreyfus Leverage Fund,
1978; director, Pfizer Inc., 1978- .
Marrett, Cora Bagley.
Professor of Sociology and Afro-American
Studies, University of Wisconsin, Madison, 1979- . Born: June 15,
1942, Richmond, Va.
Education:
Virginia Union University (BA,1963), University of Wisconsin (MA, 1965; PhD, 1968). Experience:
assistant professor of sociology, University of North Carolina,
1968-69; Western Michigan University, 1969-74: assistant professorof sociology, 1969-72, associate professor of sociology, 1972-74;
associate professor, Departments of Sociology and Afro-American
Studies, University of Wisconsin, 1974-79.
Honors & Awards: Summer
Stipend for Younger Humanists, National Endowment for the Humanities,
1972; Resident Fellow, National Academy of Sciences, 1973-74; Fellowship,
Center for Advanced Study in the Behavioral Sciences, 1976-77.
Publications:numerous articles in technical journals.
Memberships:
American Sociological Association (chairwoman, Committee on the
Status of Women in Sociology, 1972-74; Editorial Board,
American Sociologist, 1972-75; Minority Fellowship Committee, 1973-74);
Southwestern Social Science Association (Editorial Board,
Social Science Quarterly, 1972- ); Social Science Research Council(Board of Directors, 1973-80; Executive Committee, 1975-80).
Activities:
U.S. Army Scientific Advisory Panel: consultant, 1976-77, Research
Advisory Group, Institute for the Behavioral and Social Sciences,
1976-77; American Association for the Advancement of Science:
conference consultant, "Minority Women in Science and Engineering,"
1975, "Women in Basic Research Careers," 1977, conference co-organizer,"Minorities in Science," 1976; National Academy of Sciences, National
Research Council:
Social Science Panel, Advisory Committee to the
U.S. Dept. of Housing and Urban Development, 1970-71, chairwoman,workshop, "Issues in the Employment of Women," 1974; National
Science Foundation:
Advisory Panel, Minority Institutions Science
Improvement Program, 1977, Advisory Committee, Program on Ethics andValues in Science and Technology, 1977-78.
McBride, Lloyd.
International President, United Steelworkers ofAmerica, Pittsburgh, Pa., 1977- ; Vice President, AFL-CIO, 1977- .
Born: March 9, 1916, Farmington, Mo. Experience: member, Steel
Workers Organizing Committee, 1936; organizer and Negotiating Committee,
Local 1295, St. Louis, Mo., 1936; president, Local 1295, 1938-40;
president, St. Louis Industrial Union Council of CIO, 1940-42;
president, Missouri State CIO Industrial Union Council, 1942-44;
U.S. Naval Reserve, 1944-46; United Steelworkers of America, AFL-CIO,
1946:
staff union representative, 1946-58, subdistrict director,
1958-65, director, District 34 (Mo., Kan., Neb., Iowa, southern
16 0

COMMISSIONERS' BIOGRAPHIESIll.), (secretary and chairman, basic steel negotiation, Armco SteelCorp.; chairman, multi-plant bargaining, American Steel Foundries),
1965-77.
Honors & Awards: Honorary Fellow, Truman Library Institute.
Memberships:
National Urban Coalition (Board of Directors); American
Arbitration Association (director); Americans for Energy Independence(Board); National Center for Resource Recovery (Board of Directors);
National Society for the Prevention of Blindness (Board of Directors);
Salvation Army (advisory member).
Activities:
chairman, Foundry
and Forgings Industry Conference; chairman, Lead Workers Conference;delegate, International Metalworkers Federation, Geneva, Switzerland;Labor Policy Advisory Committee, U.S. Dept. of Labor; vice president,
American Immigration and Citizenship Conference; Advisory Committee
for Trade Negotiations; National Commission on Air Quality; President's
Committee on Employment of the Handicapped.
Partner; Verner, Liipfert, Bernhard, &McPherson, Harry C., Jr.
McPherson; Washington, D.C.; 1969- . Born: Aug. 22, 1929, Tyler,
Tex. Education:
University of the South (BA, 1949), Columbia
University (1949-50), University of Texas Law School (LLB, 1956).
Experience: U.S. Senate Democratic Policy Committee, 1956-63:
assistant general counsel, 1956-59, associate general counsel,
1959-61, general counsel, 1961-63; deputy under secretary of the
Army for international affairs and special assistant to the secretaryfor civil functions, 1963-64; assistant secretary of state foreducational and cultural affairs, 1964-65; special assistant andcounsel (1965-66) and special counsel (1966-69) to President Lyndon B.
Johnson.
Honors & Awards: Distinguished Civilian Service Award,
1964, U.S. Dept. of the Army; Honorary DCL, 1965, University of theSouth; Arthur S. Fleming Award, 1968. Publications: A_
Political Education (1972); Editorial Board, Foreign Affairs;
Publications Committee, The Public Interest.
Memberships:
N.Y.
Council on Foreign Relations (Board of Directors, 1974-77); Maryland
Inquiry Panel.
Activities:
John F. Kennedy Center for Performing
Arts: vice chairman, 1969-76, general counsel, 1977- ; Board ofTrustees, Woodrow Wilson International Center for Scholars, 1969-74;
chairman, Task Force on Domestic Policy, Democratic Advisory Councilof Elected Officials, 1974-76.
Peterson, Russell W.
President and Chief Executive Officer, National
Audubon Society, New York, N.Y., 1979- . Born: Oct. 3, 1916,
Portage, Wis.
Education:
University of Wisconsin (BS, 1938; PhD,
1942). Experience; E.I. DuPont de Nemours & Co., Inc., 1942-69:
research director, Textile Fabrics Division, 1954-55 and 1956-59,
merchandising manager, Textile Fibers, 1955-56, director, New Products
Division, Textile Fibers, 1959-62, director, Research and Development
Division, 1963-69; governor, State of Delaware, 1969-73; chairman,
President's Council on Environmental Quality, 1973-76; founding
president, New Directions, Washington, D.C., 1976-77; director,
Honors &Office of Technology Assessment, U.S. Congress, 1978-79.
Awards: Conservationist-of-the-Year, 1971, National Wildlife Federation;
Gold Medal Award, 1971, World Wildlife Fund; Annual Award, 1971,
Commercial Development Association; Parson's Award, 1974, American
Chemical Society; Annual Award, 1977, National Audubon Society;
Proctor Prize of Sigma Xi, 1978; Distinguished Citizen Award, National
Municipal League; Honorary Fellow, Textile Research Institute;
16 1

COMMISSIONERS' BIOGRAPHIES
honorary doctorates from:
Williams College, 1975, Stevens Instituteof Technology, 1979, Butler University, 1979, Springfield College,
numerous articles in Chemical and Engineering
1979. Publications:News, American Scientist, Smithsonian, Industry Week, Harvard Business
Review, Bioscience, The New York Times, Washington Post,
Phi Beta Kappa; Sigma Xi;
Congressional Record.
Memberships:
North-South Roundtable; International Institute for Environment andDevelopment; American Chemical Society; Federation of American
Scientists; American Ornithological Union; American Institute ofChemists (Fellow); American Association for the Advancement of
Science (director); Alliance to Save Energy (director); The World
regional vice president,
Wildlife Fund (director).
Activities:
National Municipal League, 1968- ; Board of Directors, Textile
Research Institute, 1956-69 (chairman, Executive Committee, 1959-61;
chairman, Board of Directors, 1961-63); co-chairman, Save Our Seas;
director, Tri-County Conservancy of the Brandywine; chairman, National
Education Commission of the States, 1970; chairman, National Advisory
Commission on Criminal Justice Standards and Goals, 1971-73; chairman,
Southern States Nuclear Board; chairman, Delaware River Basin Commission,
1971-72; chairman, Executive Committee, National Commission on
Critical Choices for Americans, 1973-74; vice chairman, U.S. Delegation
to the U.N. World Population Conference, 1974; vice chairman, U.S.
Delegation to the U.N. World Conference on Human Settlements, 1976.
Pigford, Thomas H.
Professor of Nuclear Engineering and Chairman,
Department of Nuclear Engineering, University of California, Berkeley,
Born:
April 21, 1922, Meridian, Miss. Education: Georgia
1959- .
Institute of Technology (BS, 1943); Massachusetts Institute ofTechnology (SM, 1948; ScD, 1952). Experience: Massachusetts Instituteinstructor of chemical engineering, 1946-47,
of Technology, 1946-57:
assistant professor of chemical and nuclear engineering, 1950-55,
associate professor, 1955-57; director, Graduate School of Engineering
Practice, Oak Ridge, Tenn., 1950-52; senior development engineer,
Aqueous Homogenous Reactor Project, Oak Ridge National Laboratory,
1952; director of engineering, director of nuclear reactor projects,
assistant director of research laboratory, General Atomic Division,
General Dynamics Corp., San Diego, Calif., 1957-59. Honors & Awards:
E. I. DuPont de Nemours Fellowship, 1948-50; Outstanding Young Manof Greater Boston, 1956; Arthur H. Compton Award, 1971, American
Nuclear Society; Fellowship, Japan Society for the Promotion of
Science, 1975; Founders Award, 1978, American Nuclear Society.
Publications:co-author, Nuclear Chemical Engineering (1957);
National
numerous research papers and articles.
Memberships:
Academy of Engineering (elected, 1976); American Nuclear Society(charter member, Fellow, former director); National Atomic Safety
and Licensing Board Panel (1963-72); American Association for the
Advancement of Science; American Institute of Chemical Engineering;
American Institute of Mechanical Engineers; Committee on Radioactive
Waste Management, National Research Council, National Academy of
Sciences.
Activities:
teaching, research, consultant to government
and various industries.
Visiting Lecturer with rank of Professor,
Taylor, Theodore B.
Mechanical and Aerospace Engineering Department, Princeton University,
1976- .
Born:
July 11, 1925, Mexico City, Mexico (parents American
16 2

COMMISSIONERS' BIOGRAPHIES
citizens). Education:
California Institute of Technology (BS,1945); Cornell University (PhD, 1954). Experience: U.S. Naval
Reserve, 1942-46; theoretical physicist, University of California
Radiation Laboratory, Berkeley, 1946-49; staff member, Los Alamos
Scientific Laboratory, 1949-56; technical director of Project Orion,
senior research advisor, General Atomic Division, General Dynamics
Corp., San Diego, Calif., 1956-64; deputy director (scientific),
Defense Atomic Support Agency, U.S. Dept. of Defense, 1964-66;
chairman of the board and founder, International Research andHonors & Awards: Ernest 0. Lawrence
Technology Corp., 1967-76.
co-author:
The Restoration ofMemorial Award, 1965.
Publications:
the Earth (1973), Nuclear Theft:
Risks and Safeguards (1974),
Nuclear Proliferation (1977), Energy: The Next Twenty Years (1979),
and author of numerous articles in technical journals and popular
media. Memberships:
American Association for the Advancement of
Science, American Physical Society, International Solar Energy
Society.
Activities:
consultant:
Air Force Science Advisory
Board, 1955-58, Los Alamos Scientific Laboratory, 1956-64, Aerospace
Corp., 1960-61, Atomic Energy Commission, 1966-70, Defense Atomic
Support Agency, 1966-69, Rockefeller Foundation, 1977-79; chairman,
Los Alamos Study Group, Air Force Space Study Commission, 1961;
Voluntary Speaker Program in Asia, U.S. Information Service, 1977-79.
Trunk, Anne D.
Resident, Middletown, Pa.; married, six children.
Born: Dec. 31, 1934, New York, N.Y. Activities: Middletown Civic
Club (president, 1971-72); Middletown Women's Club; Advisory Board,
L. J. Fink Elementary School, Middletown, Pa.; Welcome Committee,
Terre Haute, Ind.

16 3

STAFLIOFFICE OF THE CHIEF COUNSEL
Stanley M. Gorinson, Chief Counsel
Emergency Preparedness TeamCharles A. Harvey, Jr.,
Ruth Dicker
Eric Pearson

Team Leader

Role of the Managing Utility and Its Suppliers Team
Winthrop A. Rockwell, Team Leader
Joan L. GoldfrankMichael R. Hollis
Role of the Nuclear Regulatory Commission Team
Kevin P. Kane, Deputy Chief Counsel and Team Leader
Stan M. Helfman, Team Co-leader
Gary M. Sidell
Law Clerks
Jeffrey Klein
Kenneth D. Noel
Legal Assistants
Thomas S. Blood, Jr.
Louis F. Cooper
Mary Ann Hanlon
Sondra M. Korman
Leslie A. Moushey
Susan R. Paisner
Karen Randall
Dan W. Reicher
Daniel J. Sherman
Claudia A. Velletri

16 5

STAFF LISTOFFICE OF THE DIRECTOR OF TECHNICAL STAFF
Vincent L. Johnson, Director of Technical Staff
Technical Assessment Task Force
Leonard Jaffe, Head
William M. Bland, Jr.
Robert English
Ronald M. Eytchison
Dwight Reilly
William Stratton
Jasper L. Tew
Public Health and Safety Task Force
Jacob I. Fabrikant, Head
Lloyd Corwin, Advisory/Administrative AssociateJohn A. Auxier, Head, Health Physics and Dosimetry
Task Group
George W. Casarett, Head, Radiation Health Effects
Task GroupPaul M. Densen, Head, Public Health and Epidemiology Task
Group
Bruce P. Dohrenwend, Head, Behavioral Effects Task
Group
Emergency Preparedness and Response Task Force
Russell R. Dynes, Head
Quinten Johnson
Arthur H. Purcell
Robert Stallings
Philip Stern
Dennis E. Wenger
Public's Right to Information Task ForceDavid M. Rubin, Head
Holly A. Chaapel
Ann Marie Cunningham
Nadyne G. Edison
Mary Beth Franklin
Sharon M. Friedman
Wilma I. Hill
Nancy C. Joyce
Mary Paden
Roy S. Popkin
Peter M. Sandman
Mark C. Stephens
Mitchell Stephens
Patricia E. Weil
Emily Wells

16 6

STAFF LIST
Administrative Staff
Francis T. Hoban, Director of Administration
Fred Bowen, Former Director of Administration
Jeanne L. Holmberg, Administrative Officer
Betty A. Turner, Administrative Officer
Richard Sprince, Assistant to the Director
Nancy D. Watson, Staff Assistant
Barbara R. Chesnik, Research Associate/SupervisorDocument Control
Madeline Pinelli, Former Supervisor-Document Control

16 7

STAFF LISTOFFICE OF THE PUBLIC INFORMATION DIRECTOR
Barbara Jorgenson, Public Information Director
Cathryn M. Dickert, Congressional Relations/Executive Assistant to the Director
Public Information Staff
Wilma I. Hill, Media Associate
Holly A. Chaapel, Public Information AssistantMary Beth Franklin, Public Information Assistant
Administrative Staff
Wayne Fortunato-Schwandt, Administrative
Associate/Manuscript Production
Elsie E. Whited, Staff Assistant
Editorial Staff
Patrick Young, Senior Writer
Nancy C. Joyce, Staff Writer/Media Associate
Judy Ross Ferguson, Photo and Copy Editor
Joseph Foote, Production Consultant
Copy Editors
Lisa Berger
Nina Graybill
Michael F. Leccese
Vivian Noble
Claude E. Owre
Roger L. Wall

16 8

STAFF LIST
COMMISSION CONSULTANTS
Special Assistants to the Chairman
Ruth LaBombard
Elizabeth R. Dycus
Consultants to the Office of the Chief Counsel
Dennis Bakke
Ernest Gellhorn
Harold Green
Samuel W. Jensch
Richard StewartPeter Strauss
Consultants to the Technical Assessment Task ForceLouis Baker
Robert Burns
Arthur M. CarrPaul Cohen
Michael Corridini
Hans Fauske
Herb E. Feinroth
Mario Fontana
Frederick ForscherPeter Griffith
Jerry Griffiths
Raymond Heiskala
George Inskeep
John Ireland
Walter Kirchner
Dave Latham
Harry Lawroski
Saul Levy
John Mailer
Peter Mailer
Peter Mast
Margaret Mlynczak
Frank Muller
John Orndoff
Matthew Opeka
Dana Powers
A. B. Reynolds
Warren Rosenau
Robert Seale
Michael Stern
Neil E. Todreas
Beverly Washburn

16 9

STAFF LIST
Consultants to the Public Health and Safety Task ForceJames F. CrowDavid A. Hamburg
Henry S. Kaplan
Walsh McDermott
Consultants to the Health Physics and Dosimetry Task Group
Carol D. Berger
Charles M. Eisenhauer
Thomas F. Gesell
Alun R. Jones
Mary Ellen Masterson
Consultants to the Radiation Health Effects Task Group
Seymour Abrahamson
William J. Bair
Michael A Bender
Arthur D. Bloom
Victor P. Bond
Consultants to the Public Health and Epidemiology Task GroupDavid Axelrod
Maura S. Bluestone
Eugene W. Fowinkle
Kenneth G. Johnson
Ellen W. Jones
Raymond Seltser
Consultants to the Behavioral Effects Task Group
Barbara S. Dohrenwend
Stanislav V. Kasl
George J. Warheit
Consultant to the Emergency Preparedness

Task ForceJohn Ruch
Consultants to the Public's Right to Information Task Force
Alton Blakeslee
Hillier Krieghbaum
Howard J. Lewis

17 0

STAFF LISTSUPPORT STAFF
Evan M. Adelson
Margie A. Baker
Virginia Barnes
Estelle Barrios
Ruth Anne Beer
Elizabeth Brown
Robin A. Brown
Wilma 0. Bryan
Sheari Carruth
Barbara L. Cole
Gloria J. Coley
Georgia G. Davis
Simone Demers
Dan M. Einfalt
Adam M. Eisgrau
Linda FantacciFrederick W. Fisher
LaJuan M. Fowler
June H. Frazier
Ellen Glassman
Jerrold Greenberg
Barbara Harmon
Kelly L. Hilleary
Lorraine Hodge
Martha Hollister
Ada Hungerford

Barrington R. Johnson
Julie Kantrowitz
Alicia Lucas
Connie McDougal
Dennis Melby
Doris C. Miller
Jane Modatic
Sharon L. Neuenberger
Donald O'Grady
Ada Panciarelli
Kevin A. Powers
James P. Pryor
Maggie Ruiz
Sheila Elaine Saunders
Nora Schwartz
Beth Stephens
Susan Stevenson
Janet Stewart
Trisha Thompson
Diane L. Walter
Willa Weatherly
Steven R. Weiss
Pixie J. Westhoven
Ronald WoernerMary Woolard
Marily Woznicki

17 1

GLOSSARY

Auxiliary building - A structure housing a variety of equipment andlarge tanks necessary for the operation of the reactor. These
include make-up pumps, the make-up and waste gas decay tanks, andthe reactor coolant hold-up tanks.
Babcock & Wilcox (B&W) - The company that designed and supplied theTMI-2 reactor and nuclear steam supply system.
Background radiation - Radiation arising from natural radioactive
materials always present in the environment, including solar andcosmic radiation and radioactive elements in the upper atmosphere,
the ground, building materials, and the human body.
Beta particles - High-energy electrons; a form of ionizing radiationthat normally is stopped by the skin, or a very thin sheet of metal.
Bureau of Radiation Protection (BRP) - A division of Pennsylvania's
Department of Environmental Resources.
BRP is the state's leadagency in monitoring radiation releases from nuclear plants andadvises the Pennsylvania Emergency Management Agency during radiologicalemergencies.
Burns and Roe - Architectural and engineering firm responsible forthe design of TMI-2.
Candy cane - The section of pipe carrying water from the reactor toa steam generator.
Chain reaction - A self-sustaining reaction; occurs in nuclear
fission when the number of neutrons released equals or exceeds thenumber of neutrons absorbed plus the neutrons which escape from thereactor.
Cladding - In a nuclear reactor, the metal shell of the fuel rod inwhich uranium oxide pellets are stacked.
Collective dose - The sum of the individual doses received by eachmember of a certain group or population. It is calculated by multi17 3

GLOSSARY
plying the average dose per person by the number of persons within aConsequently, the collective dose isspecific geographic area.
For example, a thousand people each
expressed in person-rems.
exposed to one rem would have a collective dose of 1,000 person-rems.
Condensate booster pumps - Three pumps located between the condensate
polisher and the main feedwater pumps.
Condensate polisher - A device that removes dissolved minerals fromthe water of the feedwater system.
Condensatepumps - Three pumps in the feedwater system that pumpwater from the condensers to the condensate polishers.
Condensers - Devices that cool steam to water after the steam has
passed through the turbine.
Containment building - The structure housing the nuclear reactor;
intended to contain radioactive solids, gases, and water that might
be released from the reactor vessel in an accident.
Control rod - A rod containing material that absorbs neutrons; used
to control or halt nuclear fission in a reactor.
Core_ - The central part of a nuclear reactor that contains the fueland produces the heat.
Critical - Term used to describe a nuclear reactor that is sustaininga chain reaction.
Curie - A unit of the intensity of radioactivity in a material. A
curie is equal to 37 billion disintegrations each second.
Decay heat - Heat produced by the decay of radioactive particles; ina nuclear reactor this heat, resulting from materials left from thefission process, must be removed after reactor shutdown to preventthe core from overheating. See radioactive decay.
Design basis accident (DBA) - Hypothetical accidents evaluatedduring the safety review of nuclear power reactors. Plants are
required to have safeguards that will ensure that radiation releases
off-site will be within NRC limits should any of these accidents
occur.
Emergency core cooling system (ECCS) - A backup system designed tosupply cooling water to the reactor core in a loss-of-coolant accident.
Emergency feedwater pumps - Backup pumps intended to supply feedwater
to the steam generators should the feedwater system fail to supply
Also called auxiliary feedwater pumps.
water.
Feedwater pumps - Two large pumps capable of supplying TMI-2's twosteam generators with up to 15,500 gallons of water a minute.
17 4

GLOSSARY
Feedwater system - Water supply to the steam generators in apressurized water reactor that is converted to steam to drive turbines;
part of the secondary loop.
Fission - The splitting apart of a heavy atomic nucleus, into two or
more parts when a neutron strikes the nucleus. The splitting releasesa large amount of energy.
Fission products - Radioactive nuclei and elements formed by thefission of heavy elements.
Fuel damage - The failure of fuel rods and the release of the radioactive fission products trapped inside them. Fuel damage can occur
without a melting of the reactor's uranium.
Fuel melt - The melting of some of the uranium oxide fuel inside areactor.
Fuel rod - A tube containing fuel for a nuclear reactor.
Gamma rays - High-energy electromatic radiation; a form of ionizing
radiation, of higher energy than X-rays, that penetrates very deep
into body tissues.
General emergency - Declared by the utility when an incident at anuclear power plant poses a potentially serious threat of radiation
releases that could affect the general public.
General Public Utilities Corporation (GPU) - A utility holding
company; parent corporation of the three companies that own TMI.
Genetic defects - Health defects inherited by a child from themother and/or father.

Half-life - The time required for half of a given radioactive substanceto decay.
Health physics - The practice of protecting humans and their environment
from the possible hazards of radiation.
High pressure injection (HPI) - A pump system, capable of pumping up
to about 1,000 gallons a minute into the reactor coolant system;
part of the emergency core cooling system.
Iodine-131 - A radioactive form of iodine, with a half-life of 8.1
days, that can be absorbed by the human thyroid if inhaled or ingested
and cause non-cancerous or cancerous growths.
Ionizing radiation - Radiation capable of displacing electrons fromatoms; the process produces electrically charged atoms or ions.
Forms include gamma rays, X-rays, and beta particles.
Isolation - Condition intended to contain radioactive materials
released in a nuclear accident inside the containment building.

17 5

GLOSSARY
Krypton-85 - A radioactive noble gas, with a half-life of 10.7
years, that is not absorbed by body tissues and is soon eliminatedby the body if inhaled or ingested.
Let-down system - A means of removing water from the reactor coolant
system.
Loss-of-coolant accident (LOCA) - An accident involving a broken
pipe, stuck-open valve, or other leak in the reactor coolant systemthat results in a loss of the water cooling the reactor core.
Make-up system - A means of adding water to the reactor coolant
system during normal operation.
Make-up tank - A storage tank in the auxiliary building which provides
water for the make-up pumps.
Meltdown - The melting of fuel in a nuclear reactor after the lossof coolant water. If a significant portion of the fuel should melt,
the molten fuel could melt through the reactor vessel and releaselarge quantities of radioactive materials into the containmentbuilding.
Metropolitan Edison Company (Met Ed) - Operator and part owner of
the Three Mile Island nuclear power plant.
Millirem - 1 one-thousandth of a rem; see rem.
Natural cooling - The circulation of water without pumping by heatingwater in the core and cooling it in the steam generator.
Neutron - An uncharged particle found in the nucleus of every atom
heavier than ordinary hydrogen; neutrons sustain the fission chain
reaction in nuclear reactors.
Noble gases - Inert gases that do not react chemically and are notabsorbed by body tissues, although they may enter the blood if
inhaled into the lungs. These gases include helium, neon, krypton,
xenon, and radon.
Nuclear Regulatory Commission (NRC) - U.S. agency responsible forthe licensing and regulation of commercial, test, and research
nuclear reactors.
Nucleus - The central core of an atom.
Pennsylvania Emergency Management Agency (PEMA) - Agency responsible
for the state's response to natural and human-made disasters.
Person-rems - See collective dose.
"Poisons" - Materials that strongly absorb neutrons; used to control
or stop the fission reaction in a nuclear reactor.
17 6

GLOSSARY
Pilot-operated relief valve (PORV) - A valve on the TMI-2 pressurizer,
designed to open when steam pressure reaches 2,255 pounds per squareinch.
Potassium iodide - A chemical that readily enters the thyroid gland
when ingested.
If taken in a sufficient quantity prior to exposure
to radioactive iodine, it can prevent the thyroid from absorbing anyof the potentially harmful radioactive iodine-131.
Pressure vessel - See reactor vessel.
Pressurizer - A tank that maintains the proper reactor coolant
pressure in a pressurized water reactor.
Pressurized water reactor - A nuclear reactor system in which reactor
coolant water is kept under high pressure to keep it from boilinginto steam.
Primary system - See reactor coolant system.
Radioactive decay - The spontaneous process by which an unstableradioactive nucleus releases energy or particles to become stable.
Radioactivity - The spontaneous decay of an unstable atom. During
the decay process, ionizing radiation is usually given off.
Radiolysis - The breaking apart of a molecule by radiation, such as
the splitting of water into hydrogen and oxygen.
Reactor (nuclear) - A device in which a fission chain reaction canbe initiated, maintained, and controlled.
Reactor coolant pump - One of four large pumps used to circulate thewater cooling the core of the TMI-2 reactor.
Reactor coolant system - Water that cools the reactor core andcarries away heat.
Also called the primary loop.
Reactor vessel - The steel tank containing the reactor core; also
called the pressure vessel.
Rem - A standard unit of radiation dose. Frequently radiation doseis measured in millirems for low-level radiation; 1,000 millirems
equal one rem.
Respirator - A breathing mask that filters the air to protect against
the inhalation of radioactive materials.
Safety-related - The NRC employes several broad definitions for thisconcept.
By one, safety-related items are "structures, systems andcomponents that prevent or mitigate the consequences of postulated
accidents that could cause undue risk to the health and safety ofthe public." However, the NRC has no specific list of safety-related
items. The licensee designates what in its plant is considered
17 7

GLOSSARY
If the NRC disagrees, the question is negotiated.
safety-related.
Safety-related items receive closer quality control and assurance,
maintenance, and NRC inspection.
Saturation temperature - The temperature at which water at a given
pressure will boil; the saturation point of water at sea-level is
212° F.
Scram - The rapid shutdown of a nuclear reactor, by dropping control
rods into the core to halt fission.
Secondary system - See feedwater system.
Site emergency - Declared by the utility when an incident at anuclear power plant threatens the uncontrolled release of radioactivity
into the immediate area of the plant.
Solid system - A condition in which the entire reactor coolant
system, including the pressurizer, is filled with water.
Steam generator - A heat exchanger in which reactor coolant waterflowing through tubes heats the feedwater to produce steam.
Steam table - A chart used to determine the temperature at whichwater will boil at a given pressure.
Teratogenesis - The process of the development of gross abnormalities
in the developing unborn child; these abnormalities or birth defects
are not inherited.
Thermoluminescent dosimeter (TLD) - A device to measure nuclear
radiation.
TMI - Three Mile Island; site of two nuclear power reactors operated
by Metropolitan Edison Company.
Transient - An abnormal condition or event in a nuclear power system.
Trip - A sudden shutdown of a piece of machinery.
Turbine building - A structure housing the steam turbine, generator,and much of the feedwater system.
Uranium Oxide (UO ) - A chemical compound containing uranium andoxygen that is used as a fuel in nuclear reactors.
Waste gas decay tank - One of two auxiliary building tanks in whichradioactive gases removed from the reactor coolant are stored.
Xenon-133 - A radioactive noble gas, with a half-life of 5.3 days,
that is not absorbed by body tissues and is soon eliminated by the
body if inhaled or ingested.
Zircaloy-4 - A zirconium alloy from which fuel rod cladding is made.
17 8

Allied Pix Service, Inc., p. 136; Courtesy of U.S.
PHOTO CREDITS:
Department of Energy/EG&G, p. 108; Maps, Inc., p. 6; Courtesy ofMetropolitan Edison Company, pp. 82, 84, 85, 92, 97, 140; Bill Pierce/
CONTACT-CAMP, cover; United Press International Photos, pp. 121, 139;
Wide World Photos, pp. 80, 95, 98, 105, 110, 113, 117, 127, 128, 132.

179
* U. S. GOVERNMENT PRINTING OFFICE : 1979 0 - 303-300