REGULATORY ANALYSIS OF

REVISIONS TO 10 CFR 20

Unified Skin Dose Limit

October 2001

Prepared by:

Alan K. Roecklein, NRC

and

John W. Baum, PhD, CHP

Baum & Associates, Inc.

Radiation Safety Consultants

317 Maple Avenue

Patchogue, NY 11772
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Table of Contents

1. Statement of the Problem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

2. Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

3. Objectives of this Rulemaking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 

4. Alternatives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

5. Consequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 

6. Value Impact Analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

6.1 Routine Surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 

6.2 Follow-up Surveys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 

6.3 Nuclear Power Plant Jobs Likely to be Affected by DRPs . . . . . . . . . . . . . . . . . . 18 

a) Reactor Cavity Decontamination . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 

b) Residual Heat Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 

c) Steam Generator Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 

d) Excore Detector Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 

e) Refueling Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 

f) Upper Internal Lift Rig Decontamination . . . . . . . . . . . . . . . . . . . . . . . . . . 25 

g) Decontamination of Refueling Equipment . . . . . . . . . . . . . . . . . . . . . . . . . 26 

6.4 Protective Clothing Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 

6.5 DRP and Contamination Control Administrative Activities . . . . . . . . . . . . . . . . . . 28 

6.6 Lab Analyses of DRPs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 

6.7 NRC Surveillance Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 

6.8 NRC Costs to Implement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 

6.9 Plant Costs to Implement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 

6.10 Total of Values and Impacts for Nuclear Power Plants . . . . . . . . . . . . . . . . . . . 32 

7. Value/Impacts on Other Licensees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 
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8. Sensitivity Analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 

9. Decision Rationale . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 

9.1 Goal ñ Maintain worker and plant safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 

9.2 Goal ñ Reduce unnecessary regulatory burden . . . . . . . . . . . . . . . . . . . . . . . . . 35 

9.3 Goal ñ Increase public confidence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 

9.4 Goal ñ Increase NRC efficiency and effectiveness . . . . . . . . . . . . . . . . . . . . . . . 36 

10. References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 

Appendix A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 

Appendix B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 
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1. Statement of the Problem

Since 1985, many nuclear power plants have detected contamination of individuals and their

clothing by small, usually microscopic, highly radioactive beta or beta-gamma emitting particles

with relatively high specific activity (James, 1988; Kelly and Gustafson, 1994). These particles,

known as ?discrete radioactive particlesî (DRPs) and sometimes as ?hot particles,î most

commonly contain 60Co from corrosion products or fission products from leaking fuel. A unique

aspect of DRPs on or near the skin is that very small amounts of tissue can be exposed to very

large, highly nonuniform doses. These intense local irradiations may produce deterministic

effects such as reddening, ulceration, or necrosis of small areas of skin, but the stochastic risk

of inducing skin cancer due to a DRP exposure is negligible. The skin cancer risk from a DRP

dose at the proposed limit of 50 rem averaged over 10 cm2

 is estimated to be 4 orders of

magnitude lower than the cancer risk associated with a whole-body dose of 5 rems.

In addition to power reactors, DRPs have been occasionally encountered at facilities that

manufacture radioactive sources for calibration, medical devices, industrial gauges, and similar

devices that contain radioactive materials. Highly localized skin contaminations are also

encountered at facilities that manufacture or use high specific activity liquids, such as nuclear

medicine, radio-pharmacies, and radio-pharmaceuticals manufacturers. Although not

technically ìDRPsî, such localized contaminations share many of the key characteristics

exhibited by DRPs, mainly highly localized intense radiation fields from small to nearly

microscopic sources on the skin. 

2. Background

Prior to the revision of 10 CFR 20, the NRC issued Information Notice (IN) No. 90-48,

?Enforcement Policy for Hot Particle Exposuresî (NRC, 1990), containing a Commissionapproved policy statement. This statement indicated that enforcement discretion would be

used in cases involving occupational doses to the skin from exposure to DRPs that exceed the

skin dose limit in 10 CFR 20. IN 90-48 further stated that the provisions of this enforcement

policy would be followed by the NRC staff until a new limit applicable to DRP exposure cases

was established by revising 10 CFR 20.
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IN 90-48 explained that, for DRP exposures to the skin, the staff would use a beta emission

criterion of 75 Ci-hr (approximately 300-500 rad) for a DRP on the skin and a skin dose

criterion of 0.5 Sv (50 rem) for a DRP off the skin averaged over one cm2

 for determining

appropriate discretionary enforcement actions and appropriate severity levels. IN 90-48 stated

that the enforcement policy did not change the limits of 10 CFR 20, the methods for determining

compliance with those limits, or the notification and reporting requirements of 10 CFR Parts 19

and 20. Thus, exposures above 0.5 Sv (50 rem) were still reportable.

In 1991, the NRC revised Part 20 and its occupational dose limit for the skin of the whole body

or to any extremity to 0.5 Sv (50 rem) averaged over one cm2

 per year to prevent deterministic

effects (56 FR 23360; May 21, 1991). This dose limit for the skin is contained in 10 CFR

20.1201(a)(2)(ii) (CFR, 2000) and is intended to prevent damage to relatively large areas of the

skin that could compromise skin function or appearance. The Federal Register notice for the

final rule stated that there would be a rulemaking to set limits for skin irradiated by DRPs. This

rule responds to that commitment.

In 1989 the National Council on Radiation Protection and Measurements (NCRP) issued report

No. 106, ìLimit for Exposure to ëHot Particlesí on the Skinî (NCRP, 1989) in which it 

recommended "(1) A limit for exposure to hot particles be based on ensuring that acute deep

ulceration of the skin be prevented and that this be accomplished by a limit based on the time

integral of the beta particles emitted due to the activity of the particle in contact with the skin,

and (2) Exposure to the skin from a "point" particle or a particle of unknown size but less than 

1 mm in diameter be limited to 1010 beta particles emitted from the radionuclides contained in

the particle. For the case where 1 beta particle is emitted per disintegration, this limit may be

expressed as 10 GBq-s or 75 Ci-hr. For a particle for which the self absorption can be

measured or calculated, the limit can be increased by the ratio of the beta particles emitted by

the radionuclides divided by the beta particles emitted from the surface of the particle. 

Alternatively, the limit can be expressed as 1010 beta particles emitted from the surface of the

particle."
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These recommendations were based on consideration of both stochastic (cancer) and deep

ulceration (nonstochastic) risk estimates. At the proposed limit, the skin cancer mortality risk

estimates were considered insignificant (about a factor of 2.3 x 10-6 lower than the deep

ulceration risk) and orders of magnitude below the observed risks of mortality from accidents in

safe industries. It was also recognized by the NCRP that when small areas of skin involved in

DRP irradiation are irradiated sufficiently to cause erythema and lesions which give the

appearance of dry desquamation, such effects are temporary, are confined to an area of a few

square millimeters, and were not considered to be severe nonstochastic effects. Ulceration,

dermal thinning and pigment changes in such small areas were also not considered to be

severe nonstochastic effects. 

The NCRP recommendations were for particles on the skin. However, the Council indicated

that the circumstances in which skin is irradiated by DRPs not directly on the skin required

further study. They also indicated that "Additional research is occurring presently and should

be continued on both the biological effects of hot particles and the dosimetry of hot particles. 

Results from this ongoing work may well eventually provide sufficient new information to further

support these recommendations or to require their review at a later time."

Therefore, before rulemaking could proceed, the staff determined that additional research to

study the effects of DRPs both on and off the skin was needed to provide adequate information

to form the technical basis necessary for rulemaking. The NRC contracted with Brookhaven

National Laboratory (BNL) for this research. The research was completed in June l997 and

published as NUREG/CR-6531, ?Effects of Radioactive Hot Particles on Pig Skinî (Kaurin, et

al., 1997). This work was reviewed and commented on by numerous members of the NCRP,

the International Commission on Radiological Protection and representatives of the nuclear

power industry. The results of this work and other recent studies were considered by the

NCRP Scientific Committee 86 which published Report 130, ìBiological Effects and Exposure

Limits for ëHot Particlesí,î in 1999 (NCRP, 1999). 
6 

NCRP Report 130 provided an extensive review and summary of the scientific literature on

biological effects and dosimetry related to DRP exposures to skin and other organs. In this

review the Council discusses the problems of dosimetry for particles on clothing. In the working

environment a DRP on clothing may move relative to a specific skin site, and may be at a

variable distance from the skin. Both of these factors will result in a more homogenous dose to

a larger area of skin. The anticipated movement of a particle on clothing relative to the skin

would also make it difficult to identify the most highly exposed 1 cm2 of skin and to quantify the

exposure. Therefore, a limit was derived that would take account of a range of potential

geometries specific to DRP exposure that will prevent deep ulceration. To achieve this goal,

the Council recommended: "The dose at a depth of 70 m on skin (including ear), hair or

clothing be limited to no more than 0.5 Gy averaged over the most highly exposed 10 cm2

 of

skin." 

When applied to DRPs, this limit is mathematically equivalent to the 1010 beta particles or 

75 Ci-hr [2,775 kBq-hr] limit recommended by NCRP in Report 106, which is the current

enforcement discretion limit, and to a limit of 500 rad (5 Gy) averaged over 1 cm2

. The limit is

below the dose at which the probability for acute lesions is 50 percent for all the particle

energies studied and reviewed by the NCRP. At this limit, the risk of a stochastic effect (skin

cancer mortality) was estimated as 1.1 x 10-7. It was recognized by the NCRP that small

transient effects may occur: "However, if a biological effect were to result from a hot-particle

exposure near or exceeding the recommended limit, the result is an easily treated medical

condition still involving extremely small risk. Such occurrences would be indicative of the need

for improvement in radiation protection practices, but should not be compared in seriousness to

exceeding whole body exposure limits.î

In March of 2001 the NCRP issued Statement No. 9 which addresses "Extension of the Skin

Dose Limit for Hot Particles to Other External Sources of Skin Irradiation." In this document,

the NCRP points out that a single radioactive particle in random motion relative to the skin

could produce a dose distribution nearly equivalent to that from either distributed contamination

on the skin or an external beam that exposed the same area. The main difference is that the

instantaneous dose rate to a small area of skin near the source would be higher for a moving

DRP or a very small beam than for uniform contamination or a uniform beam delivering the
7 

same total dose over the same area. For this reason the NCRP indicated that "the absorbed

dose in skin at a depth of 70 m from any external source of irradiation be limited to 0.5 Gy 

(50 rad) averaged over the most highly exposed 10 cm2

 of skin."

To minimize the probability that exposures from DRPs would result in doses that exceed current

NRC guidelines, licensees have reduced the number of potential sources of cobalt DRPs, and

conduct rigorous DRP exposure control programs. These include more frequent surveys, e.g.,

once every two hours (which increase health physics technician exposures), and personnel

monitoring checks (which increase the workerís whole-body dose) to avoid DRP exposures to

the skin and to minimize the possibility of a reportable event. Considering the almost

nonexistent deterministic effects that are being averted, any measurable whole-body doses

attributable to monitoring workers for DRP contamination would not be considered as low as

reasonably achievable (ALARA) and should be avoided.

In addition, personnel contaminated by DRPs or high specific activity drops of liquid could in

many cases exceed the current regulatory skin dose limit of 50 rem/yr averaged over 1 cm2

before decontamination is completed successfully. Such personnel would be required by

current NRC regulations to stop all work that may lead to any additional occupational exposure

for the remainder of the calendar year. Such an action is unnecessary in view of the minimal

risk from such contaminations, and may have severe consequences on the personís

employment position, including in some cases loss of a job.

3. Objectives of this Rulemaking 

The statement of consideration published with the revised 10 CFR Part 20 (56 FR 23360, 

May 21, 1991) stated that the DRP issue would be resolved by rulemaking. The objective of

this rulemaking is to provide a risk-based skin dose limit for all sources of shallow-dose

equivalent including DRPs and small area contaminations that: (a) trades a higher risk of

occurrence of deterministic effects to the skin for a reduction in the risk of whole-body

stochastic effects, (b) reduces the unnecessary regulatory burden on licensees for reporting

exposures which have insignificant health implications, (c) aids in avoiding unnecessary wholebody exposures and possible additional non-radiological health risks such as heat stress to
8 

workers, and (d) provides a common limit for shallow-dose equivalent from all external sources

of exposure to the skin.

4. Alternatives 

Two alternatives are considered:

Alternative 1 - Make no change to Part 20.

This is the no-action option (the status quo). It is the alternative that is used for comparing

costs and benefits with the recommended Alternative 2 below. 

Alternative 2 - Propose a shallow-dose equivalent limit in ß 20.1201 for skin of 50 rem

(0.5 Sv) averaged over the 10 square centimeters of skin receiving the

highest exposure.

To determine the preferred alternative, the costs and benefits of each are evaluated, and

differences in net costs/yr and total costs discounted over a period of 20 years are estimated. 

An estimated 104 nuclear power units and a few materials licensees would be affected by the

proposed changes. Information derived from two EPRI Reports (James, 1988; and Kelly &

Gustafson, 1994), one joint EPRI/NEI report (ERS, 1997), NRC documents (Karagiannis and

Hagemeyer, 2000; NRC, 1997); from inspection reports in the NMED Database (NMED, 2001), 

and through personal contacts with staff at several plants and knowledgeable individuals, was

used in arriving at the estimates below.

James (1988) surveyed sixty-one plants for incidence of DRPs. Nineteen of these reported

finding fuel DRPs. Twenty-nine plants reported finding only activation DRPs. Kelly and

Gustafson (1994) surveyed all nuclear utilities and nuclear power plants operating in 1991. 

Ninety-nine percent of the operating power reactors (71 sites/109 reactor units) responded to

the survey. This is an exceptionally high participation rate and is indicative of the importance

that utilities placed on collecting and documenting the industryís experience with DRPs. Of the

15,068 DRPs discovered during the period covered by this report only 0.2% involved both a

skin contamination and a DRP of activity 1 Ci. Since 1991, plants have improved operations
9 

significantly. As a result only two or three plants are currently experiencing significant DRP

problems.

5. Consequences

(1) Routine area surveys of the workplace are conducted for DRPs and contamination

during operations and shutdowns at nuclear power plants as part of a DRP and

contamination-control program. The number of such surveys needed should not change

under the new rule. These surveys are made to prevent spread or release of

contamination, and even particles well below the activity value of concern for the dose

limit will continue to be searched for.

(2) Following the discovery of DRPs during maintenance operations at a nuclear power

plant, follow-up surveys are routinely employed to ensure that particles have been

adequately controlled to prevent their spread to other locations, and to prevent workers

from exceeding administrative and regulatory dose guidelines. The frequency, number

and extent of these surveys are a function of particle activity, and plant and regulatory

action levels. .

With the new dose limit one must average the dose over an area of 10 cm2

 rather than

the formerly used 1 cm2

, leaving the skin dose limit of 50 rem/yr (0.5 Sv/yr) unchanged. 

For DRPs on the skin and other small area exposures, this is mathematically equivalent

to raising the current dose limit by a factor of 10, from 50 rem (0.5 Sv) averaged over

the most highly exposed 1 cm2

 area of skin to 500 rem (5 Sv) averaged over the most

highly exposed 1 cm2

 area of skin. The new dose limit is in effect 50 rem (0.5 Sv)

averaged over the most highly exposed 10 cm2

 of skin. This will make it reasonable to

use longer working periods or ?stay timesî in those jobs likely to experience DRP or

contamination problems, and yet not exceed the dose limit. These stay times are

typically set at 2-3 hours under the current policy. Assuming the stay times are

extended by at least a factor of three, they will typically be more than six hours, which

would essentially remove the need for a worker to leave a job to check for DRPs or

contamination. Or, the number of times a surveyor will need to enter the area to check
10 

workers for DRPs will be fewer, and may be zero for most jobs. Thus, whole-body dose,

added labor time, and costs should all be reduced significantly under the new regulation.

(3) Protection from DRPs and contamination tends to increase the need for an extra layer of

protective clothing. Any reduction of needs for protective clothing will also reduce the

very important, related non-radiological hazards such as heat stress risks, and will

increase the efficiency of workers. In addition, clothing is more often discarded as

waste rather than washed if DRPs or contamination are present. However, under the

new regulation, we expect costs for clothing, laundering and surveying to be reduced

significantly since these costs are dictated primarily by contamination control needs. 

These will be less critical when dose from contamination can be averaged over 10 cm2

.

(4) Nuclear Power Plant Jobs Likely to be Affected by DRPs: 

(a) During refueling operations at nuclear power plants, the reactor cavity is

decontaminated. This operation is normally on the critical path and, at plants

experiencing DRP problems, to avoid exceeding DRP administrative action

levels, workers leave the work area to check for DRPs or contamination. This

leads to additional external whole-body dose, labor costs and power costs. The

frequency of these special checks is expected to decrease by about a factor of 

three for the few plants that will experience this problem under the new

regulation. This will result in significant savings of whole-body dose and labor

costs.

(b) In nuclear power plants, work on the Residual Heat Removal (RHR) heat

exchanger and valves is likely to result in DRP releases if the plant has had

significant fuel failures, or problems with activated cobalt particles. Workers

must leave the job periodically to check for DRPs or contamination in order to

avoid exceeding the administrative action levels and limits. The new regulation

is expected to require fewer such extra entries with resulting savings in both

whole-body dose and labor costs.
11 

(c) In PWR plants, steam generator maintenance is sometimes a critical path

job and is a significant source of DRPs and contamination for plants which have

experienced significant fuel failures or activated cobalt particles. The extra time

and whole-body dose caused by needed checks for DRPs or contamination

under the existing policy will be reduced under the new regulation. The

reduction in extra entries is expected to yield significant dose and cost savings.

(d) In PWR plants, maintenance of excore detectors is a potential source of

DRPs and contamination. Workers are often required to leave the job to check

for DRPs on their clothing, thus causing extra whole-body dose and higher labor

costs. Since this job is often on the critical path, large additional costs can result

from the extended outages. The need for these checks is expected to be

reduced under the new regulation. 

(e) Refueling operations are generally on the critical path and are occasionally

a source of DRP exposures. Delays due to the need for periodic checks for

DRPs and contamination can lead to significant whole-body dose, and increased

labor and power costs. These extra costs are expected to be reduced under the

new regulation.

(f) Decontamination of the upper internal lift rigs is another potential source of

DRPs and contamination. Workers must periodically leave the job to check for

DRPs or contamination, leading to additional whole-body dose and labor costs. 

Fewer such entries are expected under the new regulation.

(g) Decontamination of refueling equipment is an important source of DRPs and

contamination for plants with significant fuel failures or activated cobalt

problems. Workers must leave the job to check for contamination, thereby

increasing their whole-body dose and time on the job. Under the new regulation

fewer reentries will be needed, thus saving dose and labor costs.
12 

(5) DRP and contamination control training is needed to ensure workers are familiar with

the characteristics, controls and measurement requirements. Under the new regulation

the time spent on training is not expected to change significantly. 

(6) Administrative activities related to DRP activities and personal contamination incidents

will be reduced due to fewer required reports and a lower probability of over-exposures. 

(7) To assess doses to workers exposed near the dose or administrative limit, or to

evaluate the characteristics of DRPs, lab analyses are often required. Although only a

few percent of exposures need these analyses, even fewer will be needed under the

new regulation since shallow-dose equivalent will be averaged over 10 cm2

 rather than

over 1 cm2

 as required in the former regulation. For spots of highly concentrated activity

or DRPs, this is an effective increase of about a factor of ten in dose permitted to the

most highly exposed 1 cm2

 of skin. This will make it much less likely that a person will

approach the limit and hence need a careful assessment.

(8) First year NRC costs to implement the new regulation will be modest.

(9) Licensees will incur minimal costs to change procedures, train workers, and implement

the new regulations. 

6. Value/Impact Analysis

The value (benefit) and impact (cost) of the changes are estimated for NPPs in this section. 

These values represent the best estimated changes from the current baseline. From reportable

events (NMED, 2001) and existing reports (Karagiannis & Hagemeyer, 2000), it is known that

existing DRP rules as implemented are effective in protecting the licenseeís employees from

exposure to localized skin exposures. For example, during the period 1990-1999 only 11 skin

and extremity exposures were reported in the NRC's Radiation Exposure Information and

Reporting System (Karagiannis & Hagemeyer, 2000) that exceeded 500 rem averaged over 

1 cm2

, and another 30 exceeded 50 rem averaged over 1 cm2. However, these improvements

have been made at considerable cost in dose and monetary units. After an extensive survey of

105 nuclear power plants Kelly and Gustfason (1994) indicated overall cost impacts of from
13 

$200,000 to $2,000,000 annually per site. The impacts most commonly cited as resulting from

DRPs were:

# "Increased whole body exposures due to increased stay time (i.e. increased

radiological controls resulting in slower work progress).

# Increased time and manpower to do a job, thereby increasing costs.

# Heat stress due to additional heavy clothing requirements.

# Other physiological and psychological stresses on workers."

The survey also concluded: "As an overall average among the responding sites, DRPs

contributed to a 28% overall loss in productivity (28% increase in labor requirements). 

However, two sites reported an actual comparison, based on identical work, with and without

DRP controls. Based on those scenarios alone, the sites experienced an estimated loss of

33%-55% in worker productivity due to DRP control measures."

"Fifty-four percent of the respondents indicated that the implementation of DRP control

measures increases the whole body exposure of the individual radiation worker in specific DRP

zones. Moreover, 38% indicated that there is an increase in total person-rem due to increased

stay times in radiation fields in general."

"Additional DRP control measures can result in a physiological impact; existing utility

documentation suggests that this is due primarily to heat stress as a result of the additional PCs

(e.g.; double coveralls) and increased respiratory protection practices. Therefore, the

magnitude of the impact is directly proportional to the DRP control measures implemented."

"Twenty-four percent of the respondents noted that critical path was affected (i.e.; longer

outages). This was due to (and accompanied by) decreased worker efficiency."

"Two thirds of the respondents reported no impact from the implementation of IE Notice 90-48. 

The Notice reduced enforcement actions but not the requirement for treating exposures in
14 

excess of 10CFR20 exposure limits as overexposure. Thus, utilities either determined that the

Notice did not provide significant enough relief to warrant change, or the current procedures

were more conservative and, thus, more preferable. However, 28% reported some procedural

changes incidental to the Notice."

These changes in the application of the skin dose limits (i.e., averaging dose over 

10 cm2

 instead of averaging over 1 cm2) are a redefinition of acceptable DRP protection

guidelines. They are an attempt to bring into better balance the risks due to whole-body

exposures that cause stochastic effects, and localized skin exposures that lead to an increased

possibility of deterministic effects. The deterministic risks from DRP doses to small areas in

both cases are sufficiently small that there is no attempt to quantify added value or impact on

employee health. The values and impacts of the changes are all related to potential wholebody dose saving or added cost in operating an effective radiation control program at licensee

sites. In making the estimates, the following general assumptions were made:

# The changes affect 104 power reactor licensees.

# Although some non-power-reactor licensees would be affected, their operations

are not likely to be affected significantly by the changes. The costs and benefits

to these licensees are small compared to those for the power plants and,

therefore, are only considered qualitatively, and in Section 7 on sensitivity

analyses.

# Estimated labor cost is $150/hr for a power reactor licensee including all

overhead and fringe benefit costs (NRC, 1997).

# NRC labor cost is estimated at $70/hr (NRC, 1997).
15 

# Approximately 200,000 power reactor workers/yr are currently monitored for

radiation exposure. About half the monitored workers are exposed and receive a

measurable dose. Of those exposed to a measurable dose, all are potentially

exposed to DRPs.

# The average plant has a remaining lifetime of 20 years.

# The impact and value of future doses and costs were discounted at 7%/yr using

discrete (annual) discounting (NRC, 1997).

# The monetary value of dose avoided at nuclear power plants is estimated at

approximately $10,000/person-rem collective dose based on recent nuclear

power plant experience. Based on an October 2000 survey (Miller, 2001),

valuations of dose avoided employed at U. S. nuclear power plants ranged from

$5,000/person-rem to $33,000/person-rem with a median value of

$10,000/person-rem and an average of $12,682/person-rem. For these

evaluations a value of $10,000/person-rem was employed. This value is

significantly higher than the health effects value of $2,000/person-rem

recommended in NUREG/BR-0184 (NRC, 1997). The Regulatory Analysis

Guidelines clearly state that the $2,000/person-rem value relates only to health

risks. Under the guidelines, other impacts such as labor cost considerations can

and should be treated as additive elements in the NRCís value-impact analysis

and this has been done in the Regulatory Analysis. We note that this change is

cost-beneficial, even if the lower value of $2,000/person-rem were to be used. 

# Replacement power costs are $15,000/hr when critical path time is extended.

This value depends on assumptions concerning plant capacity factors and was

the approximate value that could be justified in 1993 (NRC, 1997).

These assumptions are made based on NRC data and on information obtained from industry

experts on radiation protection, licensees, and reports of the Electric Power Research Institute

in Palo Alto, California and the Nuclear Energy Institute in Washington, D.C. The estimates,

specific assumptions and rationale used are presented below item by item following the same
16 

sequential order as the discussion in Section 4. A summary of the overall values and impacts

for nuclear power plants is presented at the end of this section. Alternate assumptions were

used to test the sensitivity of results to the above values. Results from these analyses are

summarized in Section 7 below.

6.1 Routine Surveys

Concerns over potential DRP or contamination exposures and spread of particles or

contamination to clean areas leads to a need for additional routine area surveys beyond that

which is necessary to prevent spread of DRP contamination. For this report it is assumed that

approximately 4.9 hours/yr are spent doing surveys specifically for DRPs, or as supplements to

normal contamination surveys because of the concerns for DRPs. On average these surveys

are assumed to occur in radiation fields delivering 0.1 mSv/hr (10 mrem/hr) to the surveyors. It

is assumed that all 104 nuclear power plant licensees do and will continue to do these surveys.

The number of area surveys needed to prevent spread of contamination is assumed to remain

constant under the new rule. The number of extra area surveys performed to prevent DRP

contamination of workers will be reduced somewhat. Key specific assumptions in the analysis

of this attribute are:

# 104 licensees at risk

# 4.9 hours survey time required/yr

# 10 mrem/hr average dose rate

# 100 percent of licensees need to do routine surveys each year

# 20 percent fewer routine surveys will be needed under new rule

With these assumptions the total current industry costs/yr would be

[(4.9 hr x 10 mrem/hr x $10/mrem) + (4.9 hr x $150/hr)]/licensee x (104) licensees =

$127,400.

Under the new rule, costs/yr are estimated at 80 percent of those for the current rule or

0.8 x $127,400 = $101,920.
17 

The net savings per year for all licensees combined under the new rule would be

$127,400 - $101,920 = $25,480.

Assuming an average plant lifetime of 20 years, and employing a 7 percent discount rate for

future doses and costs, the total discounted savings over 20 years would be $270,088 under

the new rule. Annual dose savings of about 0.01 Sv (1 rem) are estimated.

6.2 Follow-up Surveys

This change will reduce the number of follow-up surveys required to meet plant and regulatory

guidelines on exposure to DRPs. Plants currently employ follow-up surveys whenever they

discover DRPs during routine or job-specific surveys. It is assumed that, on average, each year

1 percent of plants at risk (approximately 1) discover a significant number of particles that

require follow-up surveys that are in addition to those surveys normally required for

contamination control. It is assumed that the threshold activity for these additional surveys will

increase a factor of two to ten, due to the larger area permitted for dose averaging, following

implementation of the proposed regulation. Based on published distributions of activities

typically found in particles at nuclear power plants, it is assumed that the higher dose reporting

level will lead to the need for 34 percent fewer follow-up surveys. It is further assumed that

these surveys currently require approximately 7 hours for technicians working in fields having

average dose rates of about 0.1 mSv/hr (10 mrem/hr). Key specific assumptions in the analysis

of this attribute are:

# 104 licensees at risk

# 7 hours survey time required/yr

# 10 mrem/hr average dose rate

# 1 percent of licensees need to do additional follow-up surveys each year

# 34 percent fewer follow-up surveys are needed under the new rule

With these assumptions the total current industry costs/yr would be
18 

[(7 hr x10 mrem/hr x $10/mrem) + (7 hr x $150/hr)]/licensee x (0.01 x 104) licensees =

$1,820.

Under the new rule, costs/yr are estimated at 66 percent of those for the former rule or

0.66 x $1,820 = $1,201.

The net savings per year for all licensees combined under the new rule would be

 $1,820 - $1,201 = $619.

Assuming an average plant lifetime of 20 years, and employing a 7 percent discount rate for

future doses and costs, the total discounted savings during 20 years would be $6,559 under the

new rule. Annual dose savings of about 0.25 mSv (25 mrem) are estimated.

6.3 Nuclear Power Plant Jobs Likely to be Affected by DRPs 

The occurrences of DRP problems at nuclear power plants are related to work that breaches

the primary system. Areas where DRPs and radioactive material contamination are found

include fuel transfer pools, cask wash-down pits, steam generator cavities, fuel pits, reactor

water clean-up rooms, and in laundry rooms. Jobs in which DRPs or contamination are likely to

be found include work on control rod drives and the residual heat removal heat exchanger,

cutting thermal shields, work on incore instrumentation spent fuel cleanup schedules, irradiated

waste handling (fuel channel), and consolidation (shielding, compacting) projects. Several of

these jobs are considered below:

(a) Reactor Cavity Decontamination

Following each refueling, the reactor cavity is decontaminated. This operation is labor

intensive, involves moderate dose rates (typically about 10 mrem/hr) and is normally on the

critical path which leads to significant costs if operations are delayed. To ensure that workers

do not exceed skin dose reporting thresholds, either workers must leave the work area to

periodically check for DRPs or contamination, and/or additional health physics technicians must
19 

be assigned to monitor the workersí clothing and work areas. If a plant is experiencing

problems with DRPs, these activities can cause an additional collective whole-body dose of

from a few mSv (few hundred mrem) to several cSv (several rem). These activities can also

lead to extended outages with large costs for replacement power. In this analysis, it was

assumed that 2 percent of the plants at risk experience such problems in a typical year, causing

workers (including health physics technicians) to receive an average of 0.01 Sv (1 rem)/yr

collective whole-body dose. Additional labor time for entries and exits for contamination checks

is estimated at 50 hours for operations personnel and 50 hours for health physics personnel. 

An additional 2 hours time is needed for job planning due to DRP and contamination concerns. 

The extra surveys and reentries extend an outage by 15 hours or longer, and replacement

power costs of $15,000/hr are assumed. 

Key specific assumptions in analysis of this attribute are:

# 104 licensees at risk

# 102 hours total labor time required/yr

# 100 hours spent in 10 mrem/hr average dose rate fields

# 2 percent of licensees experience this degree of need/yr

# Outage is extended by 15 hours

# 50 percent less costs will be incurred under the new rule

# Replacement power costs $15,000/hr

With these assumptions the total industry costs/yr for this attribute would be 

[(100 hr x 10 mrem/hr x $10/mrem) + (102 hr x $150/hr) + (15 hr x $15,000/hr)]/licensee 

x (0.02 x 104) licensees = $520,624.

Under the new rule, costs are estimated at 50 percent of those for the former rule or

0.50 x $520,624 = $260,312.
20 

The net savings per year for all licensees combined under the new rule would be

 $520,624 - $260,312 = $260,312.

Assuming an average plant lifetime of 20 years, and employing a 7 percent discount rate for

future doses and costs, the total discounted savings over 20 years would be $2,759,307 under

the new rule. Annual dose savings of about 10.4 mSv (1.04 rem) are estimated.

(b) Residual Heat Removal

During maintenance on the residual heat removal system and valves, DRPs and contamination

may be released. This problem has caused doses of about 1,000 mrem/outage at some PWR

plants. For purposes of this analysis, it was assumed that 1 percent of plants may experience

this type of problem in a typical year, leading to an average additional dose of about 6.5 mSv

(650 mrem). This dose would be received during an additional 60 hours of maintenance worker

time spent on the job due to DRP and contamination surveys and reentries, plus 5 hours health

physics time for these surveys. It was assumed that no critical path time would be incurred,

and that 50 percent less effort would be expended under the new rule. 

Key specific assumptions in analysis of this attribute are:

# 69 licensees at risk

# 65 hours labor time required/yr

# 10 mrem/hr average dose rate

# 1 percent of licensees experience this degree of need/yr

# Outage is not extended

# 50 percent less costs will be incurred under the new rule

With these assumptions the total industry costs/yr for this attribute would be 

[(65 hr x 10 mrem/hr x $10/mrem) + (65 hr x $150/hr)]/licensee x (0.01 x 69)

licensees = $11,213.
21 

Under the new rule, costs are estimated at 50 percent of those for the former rule or

0.50 x $11,213 = $5,606.

The net savings per year for all licensees combined under the new rule would be

 $11,213 - $5,606 = $5,606.

Assuming an average plant lifetime of 20 years, and employing a 7 percent discount rate for

future doses and costs, the total discounted savings over 20 years would be $59,426 under the

new rule. Annual dose savings of about 2.24 mSv (224 mrem) are estimated.

(c) Steam Generator Maintenance 

Steam generator maintenance is a major recurring job at nuclear power plants. These jobs

have major potential for DRP and contamination exposures. The dose impact for steam

generator activities involving DRPs is commonly due to elevated radiation fields adjacent to the

steam generator platforms or nearby DRP survey areas. Some plants establish low dose

personnel DRP survey areas away from the steam generator platforms, thereby requiring

workers to move between the work platforms and the shielded survey area each time a DRP

personnel survey is required. If significant quantities or activities of DRPs are encountered,

these worker movements may occur on an hourly or even quarter-hour schedule. Typically

workers receive from 100 to several hundred mrem extra exposure due to needed surveys and

worker exits and reentries for DRP checks. Of the 69 PWR plants at risk, it was assumed that

1 percent have significant risk of DRP and contamination exposures It is estimated that special

surveys and worker exits and reentries for contamination checks require 50 hours worker time

and 6 hours health physics technician time, in average dose rates of 0.1 mSv/hr (10 mrem/hr). 

Of the plants experiencing problems, half are assumed to be on critical path and result in

approximately a 5 hour extension of the outage, at a cost for power of $15,000/hr. 
22 

Key specific assumptions in analysis of this attribute are:

# 69 licensees at risk

# 56 hours labor plus health physics time required/yr

# 10 mrem/hr average dose rate

# 1 percent of licensees experience this degree of need/yr

# Outage is extended by 5 hours for half of the plants affected

# 50 percent less costs will be incurred under the new rule

# Replacement power costs $15,000/hr

With these assumptions the total industry costs/yr for this attribute would be 

[(56 hr x 10 mrem/hr x $10/mrem) + (56 hr x $150/hr) + (0.5 x 5 hr x

$15,000/hr)]/licensee x (0.01 x 69) licensees = $35,535.

Under the new rule, costs are estimated at 50 percent of those for the former rule or

0.50 x $35,535 = $17,768.

The net savings per year for all licensees combined under the new rule would be

 $35,535 - $17,768 = $17,768.

Assuming an average plant lifetime of 20 years, and employing a 7 percent discount rate for

future doses and costs, the total discounted savings over 20 years would be $188,336 under

the new rule. Annual dose savings of about 1.93 mSv (193 mrem) are estimated.

(d) Excore Detector Maintenance

Maintenance of excore detectors in PWR plants can lead to significant exposures to DRP and

need for special contamination control procedures. This job typically requires an additional

whole-body exposure of about 1.9 mSv (190 mrem) due to an estimated 17 hours maintenance
23 

crew time and an estimated 2 hours health physics technician time for contamination checks

and surveys in fields averaging 10 mrem/hr. These operations are typically on critical path and

cause an estimated outage extension of about 5.75 hours at a cost of $15,000/hr.

Key specific assumptions in the analysis of this attribute are:

# 69 licensees at risk

# 19 hours labor plus health physics time required/yr

# 10 mrem/hr average dose rate

# 1 percent of licensees experience this degree of need/yr

# Outage is extended by 5.75 hours for the affected plants 

# 50 percent less costs will be incurred under the new rule

# Replacement power costs $15,000/hr

With these assumptions the total industry costs/yr for this attribute would be 

 

[(190 mrem x $10/mrem) + (19 hr x $150/hr) + (5.75 hr x $15,000/hr)]/licensee x (0.01 x

69) licensees = $62,790.

Under the new rule, costs are estimated at 50 percent of those for the former rule or

0. 5 x $62,790 = $31,395.

The net savings per year for all licensees combined under the new rule would be

 $62,790 - $31,395 = $31,395.

Assuming an average plant lifetime of 20 years, and employing a 7 percent discount rate for

future doses and costs, the total discounted savings over 20 years would be $332,787 under

the new rule. Annual dose savings of about 0.66 mSv (66 mrem) are estimated.
24 

(e) Refueling Operations

Several steps in the refueling of a reactor can lead to release of DRPs and contamination. This

item covers disassembly, cleaning and reassembly of the reactor vessel head, fuel leak testing

through "sipping," and fuel shuffling and replacement. Since refueling is normally on the critical

path, an average outage delay of 34 hours was assumed for plants experiencing DRP

problems. The refueling operations were assumed to occur in average fields of 10 mrem/hr,

and incur 32 Sv (3,200 mrem) collective dose during 300 person-hours of operator hours work

and 20 hours of health physics technician hours work. Under the new rule, it was assumed that

costs would be reduced by 50 percent due to fewer reentries and special surveys for DRPs and

contamination. 

Key specific assumptions in the analysis of this attribute are:

# 104 licensees at risk

# 320 hours labor time required/yr

# 10 mrem/hr average dose rate

# 1 percent of licensees experience this degree of need/yr

# Outage is extended by 34 hours for these plants 

# 50 percent less costs will be incurred under the new rule

# Replacement power costs $15,000/hr

With these assumptions the total industry costs/yr for this attribute would be 

 

[(320 hr x 10 mrem/hr x $10/mrem) + (320 hr x $150/hr) + (34 hr x $15,000/hr)]/licensee 

x (0.01 x 104) licensees = $613,600.

Under the new rule, costs are estimated at 50 percent of those for the former rule or

0.50 x $613,600 = $306,800.
25 

The net savings per year for all licensees combined under the new rule would be

 $613,300 - $306,800 = $306,800.

Assuming an average plant lifetime of 20 years, and employing a 7 percent discount rate for

future doses and costs, the total discounted savings over 20 years would be $3,252,080 under

the new rule. Annual dose savings of about 16.6 mSv (1,660 mrem) are estimated.

(f) Upper Internal Lift Rig Decontamination

In plants experiencing DRP problems, decontamination of the upper internal lift rig after each

refueling operation typically causes about 0.67 mSv (67 mrem) extra dose due to about 

6.7 hours of operations personnel and health physics technician time spent doing special

surveys and checks for DRPs and contamination in areas with average dose rates of 

10 mrem/hr. It is estimated that about 1 percent of plants at risk will experience DRP problems

each year. For these plants it is estimated that a 50 percent reduction in the work requirements

would be made for this job under the new rule. No reduction in work requirements or dose are

assumed for the plants not experiencing DRP problems.

Key specific assumptions in the analysis of this attribute are:

# 104 licensees at risk

# 6.7 hours labor time required/yr

# 10 mrem/hr average dose rate

# 1 percent of licensees experience this degree of need/yr

# Outage is not extended 

# 50 percent less costs will be incurred under the new rule

With these assumptions the total industry costs/yr for this attribute would be 

 

[(6.7 hr x 10 mrem/hr x $10/mrem) + (6.7 hr x $150/hr)]/licensee x (0.01 x 104)

licensees = $1,742.
26 

Under the new rule, costs are estimated at 50 percent of those for the former rule or

0.50 x $1,742 = $871.

The net savings per year for all licensees combined under the new rule would be

$1,742 - $871 = $871.

Assuming an average plant lifetime of 20 years, and employing a 7 percent discount rate for

future doses and costs, the total discounted savings over 20 years would be $9,233 under the

new rule. Annual dose savings of about 0.35 mSv (35 mrem) are estimated.

(g) Decontamination of Refueling Equipment

Post-outage decontamination of refueling equipment requires special zoning of the work area

and frequent surveys by health physics technicians to ensure that DRPs and contamination are

not released from the equipment and spread to other areas of the plant. It is estimated that

plants at risk expend about 4 hours controlling the DRP problem and about 1 percent

experience serious problems entailing about 80 hours of extra effort on the part of health

physics technicians and decontamination workers. These jobs are not on the critical path. It is

estimated that 50 percent less effort will be needed under the new rule due to the larger area

over which dose may be averaged under the new rule.

Key specific assumptions in the analysis of this attribute are therefore:

# 104 licensees at risk

# 4 hours health physics and worker time is required/yr at half of the plants at risk,

and 80 hours are required at 1 percent of the plants

# Costs will be reduced by 50 percent under the new rule
27 

With these assumptions the total industry costs for this attribute would be 

 

 (4 hr x $150/hr)/licensee x (0.5 x 104) licensees/yr + (80 hr x $150/hr)/licensee x (0.01

x 104) licensee/yr = $31,200/yr + $12,480 = $43,680/yr.

Under the new rule, costs are estimated at 50 percent of those for the former rule or

0.50 x $43,680 = $21,840/yr. 

The net savings per year for all licensees combined under the new rule would be

 $43,680 - $21,840 = $21,840.

Assuming an average plant lifetime of 20 years, and employing a 7 percent discount rate for

future doses and costs, the total discounted savings over 20 years would be $231,504 under

the new rule. No dose savings are expected.

6.4 Protective Clothing Costs at Nuclear Power Plants

Based on an EPRI study of average industry costs for replacement, disposal, and extra

monitoring of protective clothing at three nuclear power units experiencing DRP problems, it is

estimated that typical additional costs are currently about $30,000/yr at such plants. It is further

assumed that on average only 1 percent of U.S. plants are likely to need this level of control

and cost each year. Under the new rule it is assumed fewer plants will need to incur these

costs, and fewer costs will be incurred at those plants experiencing problems. It is assumed

that net costs will be reduced by 34 percent under the new rule. 

Key specific assumptions in the analysis of this attribute are:

# 104 licensees at risk

# 1 percent of licensees experience this degree of need/yr

# 34 percent less costs will be incurred under the new rule
28 

With these assumptions the current total industry costs for this attribute are 

 

0.01 x 104 plants x $30,000/plant-yr = $31,200/yr.

Under the new rule, costs are estimated at 66 percent of those for the former rule or

0.66 x $31,200 = $20,592/yr.

The net savings per year for all licensees combined under the new rule would be

 $31,200-$20,592 = $10,608.

Assuming an average plant lifetime of 20 years, and employing a 7 percent discount rate for

future doses and costs, the total discounted savings over 20 years would be $112,445 under

the new rule.

6.5 DRP and Contamination Control Administrative Activities

Routine administrative activities will be reduced under the proposed rule due to fewer incidents

needing to be investigated and reported on. Since very few incidents led to over exposures in

the past, administrative efforts will more likely relate to the reduced number of incidents that will

require reporting. Based on the change of a factor of ten in the area over which dose may be

averaged, it is estimated that the number of reportable incidents should decrease by about 50

percent under the new rule. Other administrative costs related to initial implementation of this

change are covered under item 6.9 below. In any year it is estimated that 5 percent of all plants 

at risk will need to perform administrative activities related to routine reporting of incidents and

related follow-on actions. These activities will require an average of 50 hours of plant health

physics and administrative time.

Key specific assumptions in the analysis of this attribute are therefore:

# 104 licensees at risk
29 

# 50 hours administrative time required/yr for plants experiencing this need

# 5 percent of licensees experience this degree of need/yr 

# Costs will be reduced by 50 percent under the new rule

With these assumptions the total current industry costs for this attribute would be 

(50 hr x $150/hr)/licensee x (0.05 x 104) licensees/yr = $39,000/yr.

Under the new rule, costs are estimated at 50 percent of those for the former rule or

0.5 x $39,000 = $19,500/yr. 

The net savings per year for all licensees combined under the new rule would be

$39,000 - $19,500= $19,500.

Assuming an average plant lifetime of 20 years, and employing a 7 percent discount rate for

future doses and costs, the total discounted savings over 20 years would be $206,700 under

the new rule.

6.6 Lab Analyses of DRPs at Nuclear Power Plants

The number of DRPs needing analysis varies widely with the degree of problems experienced. 

Typically, only a few particles per year will need analysis, however, for some plants, many

dozens may need analysis. It is estimated that 1 percent of plants will fall in the latter category

and cause health physics technicians and analysts to spend about 12 hours per year on this

effort. It is further estimated that the required efforts will be reduced by 10 percent under the

new rule. 

Key specific assumptions in the analysis of this attribute are therefore:

# 104 licensees at risk

# 12-hours health physics and analysts time are required/yr at affected plants 

# 1 percent of plants at risk experience this degree of need/yr
30 

# Costs will be reduced by 10 percent under the new rule

With these assumptions the current total industry costs for this attribute would be 

 

 (12 hr x $150/hr)/licensee x (0.01 x 104) licensees/yr = $1,872.

Under the new rule, costs are estimated at 90 percent of those for the former rule or

0.9 x $1,872 = $1,685/yr. 

The net savings per year for all licensees combined under the new rule would be

 $1,872 - $1,685 = $187.

Assuming an average plant lifetime of 20 years, and employing a 7 percent discount rate for

future doses and costs, the total discounted savings during a 20-year period would be $1,984

under the new rule.

6.7 NRC Surveillance Costs

Average NRC surveillance and related training and reporting time currently spent on DRP and

contamination control issues for all nuclear plants at risk is estimated at four hours per year per

plant. Under the new rule, it is estimated that costs will be reduced by 50 percent due to fewer

reports of exceeding the reporting requirement and somewhat less time spent on inspections

and training related to these issues. 

Key specific assumptions in the analysis of this attribute are therefore:

# 104 licensees at risk

# An average of 4 hours NRC staff time is required/yr/plant

# Costs will be reduced by 50 percent under the new rule
31 

With these assumptions the total costs for this attribute would be 

 

 (4 hr x $70/hr)/licensee x 104 licensees/yr = $29,120/yr.

Under the new rule, costs are estimated at 50 percent of those for the former rule or

0.5 x $29,120 = $14,560/yr.

The net savings per year for all nuclear power plant licensees combined under the new rule

would be

 $29,120 - $14,560 = $14,560.

Assuming an average plant lifetime of 20 years, and employing a 7 percent discount rate for

future doses and costs, the total discounted savings over 20 years would be $154,336 under

the new rule.

6.8 NRC Costs to Implement

Costs to implement the new rule would include those related to dissemination of information to

licensees, and training NRC inspectors. These are estimated at about $10,000 expended

primarily in the first year. For convenience of comparison with other costs, using a 7 percent

discount rate, this present value cost is expressed as an equivalent discounted annual cost of

$944/yr.

6.9 Plant Costs to Implement

To implement the new rule, all plants will need to evaluate and revise policies and procedures,

and train staff and workers. With the additional emphasis on reducing whole-body doses,

avoiding use of unnecessary protective and respiratory equipment and minimizing risks from

non-radiological factors such as heat stress, significant new training will be required. It is
32 

estimated that these activities will require an average of 80 staff and worker hours/plant to

implement during the first year yielding present value costs of

104 plants x 80 hr/plant x $150/hr = $1,248,000.

Allocating this cost over 20 years and using a 7 percent discount rate for future costs yields

$117,736/yr cost attributed to the new rule. 

6.10 Total of Values and Impacts for Nuclear Power Plants

Table 1 (Appendix A) shows a summary of the above value/impact analyses. Total savings/yr

estimated for the above jobs and functions affected by DRPs equals to $588,376/yr. Total

discounted savings estimated over 20 years for these jobs equals $6,236,785. These savings

include an estimated collective dose saving per year of about 0.0427 person-Sv (4.27 personrem). These values reflect only a portion of all jobs likely to be affected if a DRP problem is

encountered at any given plant. Other DRP-related activities that have been identified and may

result in additional dose and cost savings include: containment cavity drain line (filter suction)

work, containment sump cleanout and inspection, dryer/separator pit work for boiling water

reactors, spent fuel shuffle, transfer canal maintenance and decontamination in PWRs, spent

fuel cask handling, loading, decontamination, cask washdown (decontamination) pit sump

cleanout and inspection, control rod drive rebuilding, refuel floor area control activities, reactor

head stand control zone work, reactor coolant pump platform work, reactor coolant pump seal

decontamination/rebuild room work, residual heat removal pump room work, and primary side

valve repair. Thus, although all of the jobs analyzed above will not be affected by a problem at

any one plant, other jobs not included in the above estimates would likely be affected. 

Therefore, the overall estimate for jobs affected by DRPs and contamination at nuclear power

plants is thought to be realistic or probably conservative (on the low side).

7. Value/Impacts on Other Licensees

Of the licensees who report to the NRC, about 92 percent of the reported workers with

measurable doses were monitored by nuclear power facilities in 1999, where they received

approximately 84 percent of the total collective dose (Karagiannis & Hagemeyer, 2000). Other
33 

NRC licensees received the remaining 16 percent of collective dose. In addition, approximately

twice as many facilities are licensed to Agreement States as the number licensed by the NRC

(Karagiannis & Hagemeyer, 2000). Data from facilities licensed by agreement states are not

included in the values above. 

Little published information is available on the impacts of contamination and DRPs on nonnuclear-power and Agreement State licensees. To estimate likely impacts on these other

licenses, it is assumed that the costs (except costs for replacement power) and impacts will be

proportional to the respective collective doses. Omitting costs and savings of replacement

power leaves annual cost savings of about $159,000 for nuclear power licensees. Assuming 

non-nuclear-power NRC licenseesí savings are proportional to their collective doses relative to

those for nuclear power plants, one can estimate these savings as 16 percent of $159,000 =

$25,440/yr or $269,666 per 20 years. Also, Agreement State licensee benefits may contribute

another estimated 32 percent of the non-power-replacement nuclear power plant savings, that

is, $50,880/yr or $539,331 per 20 years. These values are also shown in Table 1 (Appendix A). 

Including these estimates with those for nuclear power plants yields a total estimated benefit of

$664,696/yr or $7,045,782 per 20 years with implementation of the new rule. 

In addition, assuming the collective doses for other licensees are reduced in proportion to

relative collective doses for nuclear power plants, the dose savings per year are estimated as

6.8 mSv/yr (0.68 rem/yr) for non-nuclear-power-plant NRC licensees, and 13.7 mSv/yr (1.37

rem/yr) for agreement state licensees. The actual values and impacts are likely to be less than

these estimates, but not negative. The added flexibility afforded by the increase in area over

which skin dose may be averaged (10 cm2

 under the new rule vs. 1 cm2 under existing

regulations) should permit more efficient work planning, less need for heavy gloves and, in

some cases extra protective clothing with resulting better utilization of the principal of ALARA

and optimization of operations to reduce whole-body doses. In any case, the impacts on other

licensees are expected to be smaller than those for nuclear-power-plant licensees, and possibly

negligible.
34 

8. Sensitivity Analyses

Values for some of the assumptions employed above are somewhat uncertain. To test the

sensitivity of the results to assumptions made, values of the following were varied and

values/impacts were recalculated and compared to the original (reference) results: 

(a) replacement power costs, (b) dollar value of dose reduction ($/person-rem), (c) plant labor

costs, and (d) NRC labor costs. Results are shown on Table 2 (Appendix B).

Replacement power costs were originally assumed to be $15,000/hr of extended outage. Since

this value was more appropriate in 1993, an increase of 20 percent to $18,000/hr was assumed

for this sensitivity test. Increased savings over original values of about $119,181/yr or

$1,263,314 over a 20-year period are estimated for the increased value of replacement power. 

This is an increase in savings of about 17.9 percent.

Values of dose avoided were tested at $2,000/person-rem saved and $16,000/person-rem

saved. The $2,000/person-rem value corresponds to the value recommended in the Regulatory

Analysis Technical Evaluation Handbook (NRC, 1997) for health effects. The $16,000/personrem value is 26 percent higher than the average employed at nuclear power plants in 2000. 

The $2,000/person-rem assumption caused a decrease in monetary savings of about 

7.6 percent/yr, whereas the increase to $16,000/person-rem caused an estimated increase in

savings of 5.7 percent/yr over values obtained with the reference assumptions.

The value of $150/hr recommended in the Regulatory Analysis Technical Evaluation Handbook

(NRC, 1997) for plant labor costs was increased to $200/hr to test for sensitivity to this

parameter. The results were estimated to increase monetary savings by $52,208/yr or 

7.9 percent over the values obtained with the reference assumptions.

Assumed NRC labor costs were increased from $70/hr to $100/hr to test for sensitivity to this

parameter. The results were estimated to increase monetary savings by $9,236/yr or 

1.4 percent over the values obtained with the reference assumptions.
35 

9. Decision Rationale

Of the two options considered, option two is preferable because it satisfies the following

decision criteria and Agency goals:

9.1 Goal ñ Maintain worker and plant safety:

# The trade off of increased deterministic skin effects for reduced whole-body

stochastic risk is based on comparative risks

# Retains assurance that large DRP skin doses that might cause significant health

effects would not occur in large numbers through the limit of 50 rem (0.5 Sv)

averaged over the highest exposed 10 cm2

 of skin

# Would reflect recommendations of the NCRP

# Provides a simplified, more easily understood regulatory approach than the

existing enforcement policy

# Reduces the need for extra layers of protective clothing, which add to heatstress for the workers, reduces worker efficiency, and adds additional wholebody dose

9.2 Goal ñ Reduce unnecessary regulatory burden:

# Reduces the frequency of job-related personnel-monitoring checks and surveys

for DRPs and contamination, thereby reducing unnecessary whole-body doses

that are incurred in attempts to avoid skin exposures due to DRPs and

contamination and current reporting requirements
36 

# Reduces the reporting burden on licensees because the reporting level is raised

from 50 rem (0.5 Sv) averaged over 1 cm2

 to 50 rem (0.5 Sv) averaged over 

10 cm2

 and few exposures are expected to exceed that level

# Would reduce and simplify the record keeping burden since the same exposure

limit (50 rem (0.5 Sv) averaged over the highest exposed 10 cm2

) would apply for

discrete particle exposures, contamination exposures and exposures to skin of

the whole body

# Would provide greater planning and operations flexibility such as deciding to use

or not use protective clothing based on considerations of other risks and the

ALARA principle, thereby improving the efficiency and cost-effectiveness of

licensee radiation protection programs

# Would reduce the number of related investigations and reports

# Responds in a positive way to the industryís request for regulatory relief

9.3 Goal ñ Increase public confidence:

# Would reflect the most recent recommendations of the NCRP and thereby

ensure appropriate radiation protection practices

# Removes the interim enforcement policy, which was a temporary solution while

more scientific data was developed

9.4 Goal ñ Increase NRC efficiency and effectiveness:

# Permits comparing all reported skin doses to a single limit

# Would reduce the number of related investigations and reports
37 

10. References

Code of Federal Regulations, Part 20 - Standards for protection against radiation, Office of the

Federal Register, 56 FR 23360, National Archives and Records, U.S. Government Printing

Office, Washington, May 21, 1991. 

Code of Federal Regulations, Part 20 - Standards for protection against radiation, Office of the

Federal Register, National Archives and Records, U.S. Government Printing Office,

Washington, January 1, 2000 revision.

ERS Corp. Case Studies on the Radiological and Economic Impact of DRP, prepared for

Electric Power Research Institute (EPRI), and Nuclear Energy Institute (NEI). ERS Corp.,

Anderson, SC, 1997.

Karagiannis, H. and D.A. Hagemeyer. Occupational Radiation Exposure at Commercial

Nuclear Power Reactors and Other Facilities 1999, NUREG-0713, Vol. 21, 2000.

James, D. W. Problem Assessment of Discrete Radioactive Particles, EPRI Report NP-5969,

Electric Power Research Institute, 1988.

Kaurin, D. G. L., Baum, J. W., Carsten, A. L. Archambeau, J. O., and Schaefer, C. W. Effects

of Radioactive Hot Particles on Pig Skin. U.S. Nuclear Regulatory Commission; 

NUREG/CR-6531, 1997.

Kelly, J. J. and Gustafson, G. Industry Experience with Discrete Radioactive Particles, EPRI

Report TR-104125, Electric Power Research Institute,1994.

Miller, David W., Personal communication, 2001.

National Council on Radiation Protection and Measurements. Limit for Exposure to "Hot

Particles" on the Skin. Bethesda, Maryland: National Council on Radiation Protection and

Measurements, NCRP Report No. 106; 1989.
38 

National Council on Radiation Protection and Measurements. Biological Effects and Exposure

Limits for ìHot Particles.î Bethesda, Maryland: National Council on Radiation Protection and

Measurements, NCRP Report No. 130; 1999.

Nuclear Regulatory Commission. Regulatory Analysis Technical Evaluation Handbook,

NUREG/BR-0184, 1997.

NRC Information Notice 90-48, ?Enforcement Policy for Hot Particle Exposures,î August 2,

1990.

NMED Search Results, http://nmed.inel.gov, January 30, 2001.
39 

Appendix A

 Table 1. Summary of Value/Impact Analyses.

 Savings/yr Disc. Savings Total Dose

 Item with New Summed Savings/yr

 Rule Over 20 yrs (person-rem)*

1. Routine Surveys $25,480 $270,088 1.02 

2. Follow-up Surveys $619 $6,559 0.02 

3. Reactor Cavity Decon $260,312 $2,759,307 1.04 

4. RHR Heat Ex. & Valves $5,606 $59,426 0.22 

5. Steam Gen. Main. $17,768 $188,336 0.19 

6. Excore Detector $31,395 $332,787 0.07 

7. Refueling $306,800 $3,252,080 1.66 

8. Upper Int. Lift Rig Decon $871 $9,233 0.03 

9. Decon of Refuel Equip $21,840 $231,504 0.00 

10. Prot. Clothing Costs $10,608 $112,445 0.00 

11. DRP Admin. Activities $19,500 $206,700 0.00 

12. Lab Analyses of DRPs $187 $1,984 0.00 

13. NRC Surveillance Costs $14,560 $154,336 0.00 

14. NRC Costs to Implement ($944) ($10,000) 0.00 

15. Plant Costs to Implement ($117,736) ($1,248,000) 0.00 

Nuclear Power Plant Totals: $596,866 $6,326,785 4.27 

Non-Power-Plant Licensees: $25,440 $269,666 0.68 

Agreement State Licensees: $50,880 $539,331 1.37 

 Grand Totals: $673,186 $7,135,782 6.31 

*100 rem = 1 Sv
40 

Appendix B

 Table 2. Results of Sensitivity Analyses. 

Variable Value Benefit/yr Benefit/20yr Change/yr Change/20yr % change

(base case) $664,696 $7,045,782 $0 $0 0.0 

Power $18,000/hr $783,877 $8,309,096 $119,181 $1,263,314 17.9 

$/person-rem* $2,000 $614,189 $651,408 ($50,507) ($535,374) -7.6 

$/person-rem* $16,000 $702,577 $7,447,312 $37,881 $401,530 5.7 

Plant Labor $200/hr $716,904 $7,599,182 $52,208 $553,400 7.9 

NRC Labor $100/hr $673,932 $7,143,675 $9,236 $97,893 1.4 

*$1,000/person-rem = $100,000/person-Sv