[Federal Register Volume 60, Number 34 (Tuesday, February 21, 1995)]
[Proposed Rules]
[Pages 9634-9645]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-4167]



-----------------------------------------------------------------------


NUCLEAR REGULATORY COMMISSION
10 CFR Part 50

RIN 3150-AF00


Primary Reactor Containment Leakage Testing for Water-Cooled 
Power Reactors

AGENCY: Nuclear Regulatory Commission.

ACTION: Proposed rule.

-----------------------------------------------------------------------

SUMMARY: The Nuclear Regulatory Commission is proposing to amend its 
regulations to provide a performance-based option for leakage rate 
testing of containments of light-water-cooled nuclear power plants. 
This option will be available for voluntary adoption by licensees, in 
lieu of compliance with the current prescriptive requirements contained 
in the current regulation. This action is aimed at improving the focus 
of the regulations by eliminating prescriptive requirements that are 
marginal to safety. The proposed rule would allow test intervals to be 
based on system and component performance, and provide licensees 
greater flexibility for cost-effective implementation methods of 
regulatory safety objectives.

DATES: Submit comments by May 8, 1995. Comments received after this 
date will be considered if it is practical to do so, but the Commission 
is able to assure consideration only for comments received on or before 
this date.

ADDRESSES: Send comments to: Secretary, U.S. Nuclear Regulatory 
Commission, Washington, DC 20555. ATTN: Docketing and Service Branch.
    Hand deliver comments to: 11555 Rockville Pike, Rockville, 
Maryland, between 7:45 a.m. and 4:15 p.m. Federal workdays.
    Comments may be submitted electronically, in either ASCII text or 
Wordperfect format (version 5.1 or later), by calling the NRC 
Electronic Bulletin Board on FedWorld. The bulletin board may be 
accessed using a personal computer, a modem, and one of the commonly 
available communications software packages, or directly via Internet. 
Background documents on the rulemaking are also available for 
downloading and viewing on the bulletin board.
    If using a personal computer and modem, the NRC subsystem on 
FedWorld can be accessed directly by dialing the toll free number: 1-
800-303-9672. Communication software parameters should be set as 
follows: Parity to none, data bits to 8, and stop bits to 1 (N,8,1). 
Using ANSI or VT-100 terminal emulation, the NRC rulemaking subsystems 
can then be accessed by selecting the ``Rules Menu'' option from the 
``NRC Main Menu.'' For further information about options available for 
NRC at FedWorld consult the ``Help/Information Center'' from the ``NRC 
Main Menu.'' Users will find the ``FedWorld Online User's Guides'' 
particularly helpful. Many NRC subsystems and databases also have a 
``Help/Information Center'' option that is tailored to the particular 
subsystem.
    The NRC subsystem on FedWorld can also be accessed by a direct dial 
phone number for the main FedWorld BBS: 703-321-8020; Telnet via 
Internet: fedworld.gov (192.239.93.3); File Transfer Protocol (FTP) via 
Internet: ftp.fedworld.gov (192.239.92.205); and World Wide Web using: 
http:// [[Page 9635]] www.fedworld.gov (this is the Uniform Resource 
Locator (URL)).
    If using a method other than the toll free number to contact 
FedWorld, then the NRC subsystem will be accessed from the main 
FedWorld menu by selecting the ``F--Regulatory, Government 
Administration and State Systems,'' then selecting ``A--Regulatory 
Information Mall''. At that point, a menu will be displayed that has an 
option ``A--U.S. Nuclear Regulatory Commission'' that will take you to 
the NRC Online main menu. You can also go directly to the NRC Online 
area by typing ``/go nrc'' at a FedWorld command line. If you access 
NRC from FedWorld's main menu, then you may return to FedWorld by 
selecting the ``Return to FedWorld'' option from the NRC Online Main 
Menu. However, if you access NRC at FedWorld by using NRC's toll-free 
number, then you will have full access to all NRC systems, but you will 
not have access to the main FedWorld system. For more information on 
NRC bulletin boards call Mr. Arthur Davis, Systems Integration and 
Development Branch, U.S. Nuclear Regulatory Commission, Washington, DC 
20555, telephone (301) 415-5780; e-mail AXD<a href="/cdn-cgi/l/email-protection#1f2c5f716d7c31787069"><span class="__cf_email__" data-cfemail="182b58766a7b367f776e">[email protected]</span></a>.
    Examine comments received, the draft environmental assessment and 
findings of no significant impact, and the draft regulatory analysis 
at: The NRC Public Document Room, 2120 L Street NW. (Lower Level), 
Washington, DC; the PDR's mailing address is Mail Stop LL-6, 
Washington, DC 20555; phone (202) 634-3273; fax (202) 634-3343. Copies 
of the documents may be obtained from the PDR for a fee. These 
documents may also be viewed and downloaded electronically via the 
Electronic Bulletin Board established by NRC for this rulemaking.
    The NRC also requests public comment on Draft NUREG-1493, 
``Performance-Based Containment Leak Test Program.'' A free single copy 
of draft NUREG-1493 may be requested by written request to the U.S. 
Nuclear Regulatory Commission, ATTN: Distribution Section, Room P1-37, 
Washington, DC 20555; fax (301) 504-2260. Comments on draft NUREG-1493 
may be submitted to: Chief, Rules Review and Directives Branch, 
Division of Freedom of Information and Publication Services, Mail Stop 
T-6D59, U.S. Nuclear Regulatory Commission, Washington, DC 20555. Hand 
deliver comments on draft NUREG-1493 to 11545 Rockville Pike, Maryland 
between 7:45 a.m. and 4:15 p.m. on Federal workdays. Comments on draft 
NUREG-1493 may be submitted electronically as indicated above under the 
ADDRESSES heading.

FOR FURTHER INFORMATION CONTACT: Dr. Moni Dey, Office of Nuclear 
Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 
20555, telephone (301) 415-6443, e-mail <a href="/cdn-cgi/l/email-protection#563b3d321638243578313920"><span class="__cf_email__" data-cfemail="5835333c18362a3b763f372e">[email protected]</span></a>

SUPPLEMENTARY INFORMATION:
Background

    The NRC is proposing to amend 10 CFR part 50, appendix J in an 
effort to relax and allow alternatives to those requirements that are 
prescriptive and marginal to safety and yet impose a significant 
regulatory burden on licensees. NRC reactor licensees are required 
currently to conduct periodic primary reactor containment leakage 
testing in accordance with 10 CFR part 50, appendix J, ``Primary 
Reactor Containment Leakage Testing for Water-Cooled Power Reactors.'' 
Appendix J is currently prescriptive in that it specifies leak test 
frequencies, pretest requirements, test methods, and reporting 
requirements.

NRC's Marginal to Safety/Regulatory Improvement Program

    In 1984, the NRC staff initiated a program to make regulatory 
requirements more efficient by eliminating those with marginal impact 
on safety. The NRC's initiative to eliminate requirements marginal to 
safety recognizes both the dynamic nature of the regulatory process and 
that the importance and safety contribution of some existing regulatory 
requirements may not have been accurately predicted when adopted or may 
have diminished with time. The availability of new technical 
information and methods justify a review and modification of existing 
requirements.
    The NRC solicited comments from industry on specific regulatory 
requirements and associated regulatory positions that needed 
reevaluation. The Atomic Industrial Forum conducted a survey providing 
most of industry's input, published for the NRC as NUREG/CR-4330<SUP>1, 
``Review of Light Water Reactor Regulatory Requirements,'' Vol. 1, 
April 1986. A list of 45 candidates for potential regulatory 
modification were identified. The NRC's review of the list selected 
Appendix J as one of seven areas requiring further analysis (NUREG/CR-
4330, Vols. 2 and 3, dated June 1986 and May 1987). The NRC also 
conducted a survey of its staff concerning their expertise in a 
particular area, experience in regulation, and knowledge of regulatory 
requirements. The NRC staff survey identified 54 candidates, a number 
of which were previously identified in the earlier survey. The NRC's 
assessment of this list also selected appendix J as a potential 
candidate for modification.

    \1\Copies of NUREGs may be purchased from the Superintendent of 
Documents, U.S. Government Printing Office, P.O. Box 37082, 
Washington, DC 20013/7082. Copies are also available from the 
National Technical Information Service, 5285 Port Royal Road, 
Springfield, VA 22161. A copy is available for inspection and/or 
copying in the NRC Public Document Room, 2120 L Street, NW. (Lower 
Level), Washington, DC.
---------------------------------------------------------------------------

    The NRC published in the Federal Register, for comment, a proposed 
revision to appendix J on October 29, 1986 (51 FR 39538) to update 
acceptance criteria and test methods based on experience in applying 
the existing requirements and advances in containment leak testing 
methods, resolve interpretive questions, and reduce the number of 
exemption requests. The October 29, 1986, proposed rule is being 
withdrawn from further consideration and a more comprehensive proposed 
rule that accounts for the latest technical information and regulatory 
framework is being proposed.
    The NRC's Marginal-to-Safety initiative is part of a broader NRC 
initiative for regulatory improvement. Through its Program for 
Regulatory Improvement, the NRC has institutionalized an ongoing effort 
to eliminate requirements marginal to safety and to reduce regulatory 
burden. The NRC staff's plan in SECY-94-090, dated March 31, 1994, 
which satisfies the recent requirement for a periodic review of 
existing regulations in Executive Order 12866 of September 30, 1993, 
was approved by the Commission on May 18, 1994. The Regulatory 
Improvement Program is aimed at the fundamental principle adopted by 
the Commission that all regulatory burdens must be justified and that 
its regulatory process must be efficient. In practice, this means the 
elimination or modification of requirements where burdens are not 
commensurate with their safety significance. The activities of the 
Regulatory Improvement Program should result in enhanced regulatory 
focus in areas that are more safety significant. As a result, an 
overall net increase in safety is expected from the program.
    The Regulatory Improvement Program will include, whenever feasible 
and appropriate, the consideration of performance-oriented and risk-
based approaches. The program will review requirements or license 
conditions that are identified as a significant burden on 
[[Page 9636]] licensees. If review and analysis find that the 
requirements are marginal to safety, they would be eliminated or 
relaxed. By performance-oriented, the NRC means establishing regulatory 
objectives without prescribing the methods or hardware necessary to 
accomplish the objective, and allowing licensees the flexibility to 
propose cost-effective methods for implementation. By risk-based, the 
NRC means regulatory approaches that use probability risk analysis 
(PRA) as the systematic framework for developing or modifying 
requirements.
    The present rulemaking is part of this overall effort and 
initiative for eliminating requirements that are marginal to safety and 
is guided by the policies, framework and criteria for the program.
    The NRC published a notice in the Federal Register on February 4, 
1992 (57 FR 4166), presenting its conclusion that appendix J was a 
candidate whose requirements may be relaxed or eliminated based on 
cost-benefit considerations. On the basis of NRC staff analyses of 
public comments on the proposal, the Commission approved and announced 
on November 24, 1992 (57 FR 55156) its plans to initiate rulemaking for 
developing a performance-oriented and risk-based regulation for 
containment testing requirements. On January 27, 1993, (58 FR 6196) the 
NRC staff published a general framework for developing performance-
oriented and risk-based regulations and, at a public workshop on April 
27 and 28, 1993, invited discussions of specific proposals for 
modifying containment testing requirements. Industry and public 
comments on the proposals, and other recommendations and innovative 
ideas raised at the public workshop, were documented in the proceedings 
of the workshop (NUREG/CP-0129, September 1993). Specifically, the NRC 
concluded that the allowable containment leakage rate utilized in 
containment testing may be increased and other Appendix J requirements 
need not be as prescriptive as the current requirements. To increase 
flexibility, the detailed and prescriptive technical requirements 
contained in appendix J regulations could be improved and replaced with 
performance-based requirements and supporting regulatory guides. The 
regulatory guides would allow alternative approaches, although 
compliance with current existing regulatory requirements would continue 
to be acceptable. The performance-based requirements would reward 
superior operating practices.

Performance-Based Regulatory Approach

    In institutionalizing the Regulatory Improvement program and 
adopting a performance-based regulatory approach, the NRC has 
formulated the following framework for revisions to its regulations:
    (1) The new performance-based regulation will be less prescriptive 
and allow licensees flexibility to adopt cost-effective methods for 
implementing the safety objectives of the original rule.
    (2) The regulatory safety objectives will be derived, to the extent 
feasible and practical, from risk considerations with appropriate 
consideration of uncertainties, and will be consistent with the NRC's 
Safety Goals.
    (3) Detailed technical methods for measuring or judging the 
acceptability of a licensee's performance relative to the regulatory 
safety objectives will be, to the extent practical, provided in 
industry standards and guidance documents which are endorsed in NRC 
regulatory guides.
    (4) The new regulation will be optional for current licensees so 
that licensees can decide to remain in compliance with current 
regulations.
    (5) The regulation will be supported by necessary modifications to, 
or development of, the full body of regulatory practice including, for 
example, standard review plans, inspection procedures, guides, and 
other regulatory documents.
    (6) The new regulation will be formulated to provide incentives for 
innovations leading to improvements in safety through better design, 
construction, operating, or maintenance practices.

Current Appendix J Requirements

    Appendix J to 10 CFR part 50, ``Primary Reactor Containment Leakage 
Testing for Water-Cooled Power Reactors,'' became effective on March 
16, 1973. The regulatory safety objective of reactor containment design 
is stated in 10 CFR part 50, appendix A, ``General Design Criteria for 
Nuclear Power Plants,'' Criterion No. 16, ``Containment Design.'' GDC 
Criterion 16 mandates ``an essentially leak-tight barrier against the 
uncontrolled release of radioactivity to the environment * * *'' for 
postulated accidents. Appendix J to 10 CFR part 50 implements, in part, 
General Design Criterion No. 16 and specifies containment leakage 
testing requirements, including the types of tests required. For each 
type of test required, Appendix J specifies how the tests should be 
conducted, the frequency of testing, and reporting requirements. 
Appendix J requires the following types of containment leak tests:
    (1) Measurement of the containment integrated leak-rate (Type A 
tests, often referred to as ILRTs).
    (2) Measurement of the leak-rate across each pressure-containing or 
leakage-limiting boundary for various primary reactor containment 
penetrations (Type B tests).
    (3) Measurement of the containment isolation valves leak-rates 
(Type C tests).
    Type B and C tests are referred to as local leak-rate tests 
(LLRTs).

Leak-Tightness Requirements

    Compliance with 10 CFR part 50, appendix J, requirements is 
determined by comparing the measured containment leak-rate with the 
maximum allowable leak rate. Maximum allowable leak-rates are 
calculated in accordance with 10 CFR Part 100, ``Reactor Site 
Criteria,'' and are incorporated into the technical specifications. 
Typical allowable leak-rates are 0.1 percent of containment volume per 
day for pressurized water reactors (PWRs) and one volume percent per 
day for boiling water reactors (BWRs).

Test Frequency Requirements

    Schedules for conducting containment leak-rate tests are specified 
in appendix J for both preoperational and periodic tests. Periodic 
leak-rate tests schedules are as follows:
    Type A Tests. (1) After the preoperational leak-rate test, a set of 
three Type A tests must be performed at approximately equal intervals 
during each 10-year service period. The third test of each set must be 
conducted when the plant is shutdown for the 10-year plant in-service 
inspection.
    (2) The performance of Type A tests must be limited to periods when 
the plant facility is nonoperational and secured in the shutdown 
condition under the administrative control and in accordance with the 
safety procedures defined in the license.
    (3) If any periodic Type A test fails to meet the applicable 
acceptance criteria, the test schedule applicable to subsequent Type A 
tests will be reviewed and approved by the Commission. If two 
consecutive periodic Type A tests fail to meet the applicable 
acceptance criteria, a Type A test must be performed at each plant 
shutdown for refueling or approximately every 18 months, whichever 
occurs first, until two consecutive Type A tests meet the acceptance 
criteria, after which time the regular retest schedule may be resumed. 
[[Page 9637]] 
    Type B Tests. (1) Except for airlocks, Type B tests must be 
performed during reactor shutdown for refueling, or other convenient 
intervals, but in no case at intervals greater than 2 years. If opened 
following a Type A or B test, containment penetrations subject to Type 
B testing must be tested prior to returning the reactor to an operating 
mode requiring containment integrity. For primary reactor containment 
penetrations employing a continuous leakage monitoring system, Type B 
tests, except for tests of airlocks, may be performed every other 
reactor shutdown for refueling but in no case at intervals greater than 
3 years.
    (2) Airlocks must be tested prior to initial fuel loading and at 6-
month intervals thereafter. Airlocks opened during periods when 
containment integrity is not required by the plant's technical 
specifications must be tested at the end of such periods. Airlocks 
opened during periods when containment integrity is required by the 
plant's technical specifications must be tested within 3 days after 
being opened. For airlock doors opened more frequently than once every 
3 days, the airlock must be tested at least once every 3 days during 
the period of frequent openings. For airlock doors having testable 
seals, testing the seals fulfills the 3-day test requirement. Airlock 
door seal testing must not be substituted for the 6-month test of the 
entire airlock at not less than P<INF>a, the calculated peak 
containment pressure related to the design basis accident.
    Type C Tests. Type C tests must be performed during each reactor 
shutdown for refueling but in no case at intervals greater than 2 
years.
    There have been two amendments to this appendix since 1973. The 
first amendment published September 22, 1980 (45 FR 62789), modified 
the Type B penetration test requirements to conform to what had become 
accepted practice through the granting of exemptions. The second 
amendment published November 15, 1988 (53 FR 45890) incorporated the 
Mass Point statistical analysis technique as a permissible alternative 
to the Total Time and Point-to-Point techniques specified in appendix 
J.

European Experience

    A combination of Type A tests and an on-line monitoring (OLM) 
capability is being actively pursued in Europe, notably in France and 
Belgium, and is currently being considered in Sweden. OLM is used to 
identify a ``normal'' containment pressurization pattern and to detect 
deviations from that pattern. The Belgians conduct a leak test using 
OLM during reactor operation after each cold shutdown longer than 15 
days with the objective of detecting gross leaks. The objective of the 
Belgian approach to Type A testing is to reduce the frequency and 
duration of the tests. The Type A test is conducted at a containment 
pressure (P<INF>t) not less than half of the peak pressure (0.5 
P<INF>a). It is performed once every 10 years.
    In France, containment leaktightness is being continuously 
monitored during reactor operation in all of the French PWR plants 
using the SEXTEN system. It is also being evaluated by the Swedes for 
their PWR units. Leaks may be detected during the positive or negative 
pressure periods in the containment by evaluating the air mass balance 
in the containment. Type A tests are conducted at containment peak 
pressure (loss-of-coolant accident pressure) before initial plant 
startup, during the first refueling, and thereafter every 10 years 
unless a degradation in containment leak-tightness is detected. In that 
case, tests are conducted more frequently.
    Further details of European approaches to containment testing is 
provided in Draft NUREG-1493.

Advance Notices for Rulemaking and Public Comments

    Over time, it has become apparent that variations in plant design 
and operation frequently make it difficult to meet some of the 
requirements contained in appendix J because of its prescriptive 
nature. Economic and occupational exposure costs are directly related 
to the frequency of containment testing. Containment integrated leak 
rate tests (Type A) preclude any other reactor maintenance activities 
and thus are on the critical path for return to service from reactor 
outages. In addition to the costs of the tests, integrated leak tests 
impose the added burden of the cost of replacement power. Containment 
penetration leak tests (Type B and C) can be conducted during reactor 
shutdowns in parallel with other activities and thus tend to be less 
costly; however, the large number of penetrations impose a significant 
burden on the utilities. Additionally, risk assessments performed to 
date indicate that the allowable leak rate from containments can be 
increased, and that control of containment leakage at the current low 
rates is not as risk significant as previously assumed.<SUP>2 3

    \2\Severe Accident Risks: An assessment for five U.S. Nuclear 
Power Plants, Final Summary Report.'' NUREG-1150, December 1990. 
Copies of NUREGs may be purchased from the Superintendent of 
Documents, U.S. Government Printing Office, P.O. Box 37082, 
Washington, DC 20013/7082. Copies are also available from the 
National Technical Information Service, 5285 Port Royal Road, 
Springfield, VA 22161. A copy is available for inspection and/or 
copying in the NRC Public Document Room, 2120 L Street, NW. (Lower 
Level), Washington, DC.
    \3\Performance-Based Containment Leak Test Program,'' Draft 
NUREG-1493, January 1995. A free single copy of draft-1493 may be 
requested by those considering public comment by writing to the U. 
S. Nuclear Regulatory Commission, ATTN: Distribution Section, Room 
P1-37, Washington, DC 20555. A copy is also available for inspection 
and/or copying in the NRC Public Document Room, 2120 L Street, NW. 
(Lower Level), Washington, DC 20555.
---------------------------------------------------------------------------

Initial NRC Proposal

    In August of 1992, the Commission initiated a rulemaking to modify 
appendix J to make it less prescriptive and more performance-oriented. 
The Commission also initiated a plan to relax the allowable containment 
leak-rate utilized to define performance standards for containment 
tests. In the Federal Register published on January 27, 1993 (58 FR 
6196), the NRC indicated the following potential modifications to 
appendix J of 10 CFR part 50 would be considered:
    (1) Increase allowable containment leak-rates based on Safety Goals 
and PRA technology (i.e., define a new performance standard).
    (2) Modify appendix J to be a performance-based regulation:
    A  Limit the revised rule to a new regulatory objective: In order 
to ensure the availability of the containment during postulated 
accidents, licensees should either:
    (i) Test overall containment leakage at intervals not longer than 
every 10 years, and test pressure-containing or leakage-limiting 
boundaries and containment isolation valves on an interval based on the 
performance history of the equipment; or
    (ii) Provide on-line (i.e., continuous) monitoring of containment 
isolation status.
    B  Remove prescriptive requirements from appendix J and preserve 
useful portions as guidance in a NRC regulatory guide.
    C  Endorse industry standards on:
    (i) Guidance for calculating plant-specific allowable leak-rates 
based on new NRC performance standard;
    (ii) Guidance on the conduct of containment tests; and
    (iii) Guidance for on-line monitoring of containment isolation 
status. [[Page 9638]] 
    D  Continue to accept compliance with the current detailed 
requirements in appendix J (i.e., licensees presently in compliance 
with Appendix J will not need to do anything if they do not wish to 
change their practice).
    A public workshop on the subject was held by the NRC on April 27 
and 28, 1993.<SUP>4

    \4\``Workshop on Program for Elimination of Requirements 
Marginal to Safety.'' NUREG/CP-0129, September 1994.
---------------------------------------------------------------------------

Public Comments and Issues

    Listed below are the categories of relevant issues identified by 
the public, the nuclear industry, and the NRC at the public workshop 
and in response to earlier solicitations for comments on this 
rulemaking, and a summary of interests expressed. Summaries of 
individual comments earlier solicitations were published on November 
1992 (57 FR 55156). The comments at the public workshop are documented 
in NUREG/CP-0129, September 1993. The comments are available for 
inspection in the NRC Public Document Room.
    1. Is there a continuing need for this regulation?
    Most commenters agree that there is a continuing need for a 
regulation on containment leak testing. While some commenters believe 
the regulation should be tightened, most commenters believe appendix J 
requirements should be relaxed. Industry representatives presented a 
wealth of data on the cost and benefits of containment leak testing.
    2. Should the NRC replace appendix J to 10 CFR part 50, ``Primary 
Reactor Containment Leak Testing for Water-Cooled Power Reactors,'' 
with a non-prescriptive, performance-based rule?
    One commenter believed that using conservatism that may far exceed 
performance-based regulations is in the public's interest. Some 
misallocation of resources does exist that could be corrected, although 
there may be varying opinions concerning where they are. One commenter 
believed that, from a public perception viewpoint, there would be 
dissatisfaction with changing to performance-based regulation. It 
appears to represent a streamlining or deregulation of standards. 
Another view held that because there is no consistent regulatory basis, 
there are inconsistencies in regulation. Performance-based regulations 
would get rid of these inconsistencies. A move to performance-based 
regulations would uncover marginal requirements. Performance-based 
requirements would depend on the functional importance of a component 
and might include deterministic performance standards for components. A 
component that did not meet the performance standard would be rejected. 
Another view was that the industry can use increased knowledge about 
reactors and regulations within the existing technology to improve the 
regulations and reduce risk, without relying on risk assessments. This 
approach might result in earlier benefits. Industry generally 
encouraged the NRC to proceed with its initiative to decrease the 
prescriptiveness of its regulations and adopt more performance-based 
approaches.
    3. Should the NRC increase allowable containment leakage rates?
    Some commenters believe that the existing appendix J requirements 
for allowable leakage should not be relaxed and, based on their 
interpretation of NUREG/CR-5747, ``Estimate of Radionuclide Releases 
Characteristics into Containment Under Severe Accident Conditions,'' 
suggests that more stringent leakage limits, not relaxation of these 
requirements, is appropriate. Because the current leakage rates 
specified in plant technical specifications are based on relatively 
conservative assumptions, the majority of commenters believe that a 
more realistic representation of loss-of-coolant accidents should be 
used to calculate dose to the public. These commenters believe that 
more realistic accident scenarios would support a relaxation in the 
containment leak-rate.
    4. Should the NRC decrease Type A, B, and C test frequencies?
    While some commenters had opinions on proper test frequencies, and 
most believed that test frequencies could be relaxed, overall, the 
technical community believed that examination of the technical data and 
the objectives of the test should be used to determine the appropriate 
test frequency. One commenter believed that both increased and 
decreased frequencies might be appropriate. For example, tests might be 
increased in frequency for valves that play a risk-significant role, 
and test interval or allowable leak-rate could be increased for less 
important components.
    5. Can the new rule and its implementation yield an equivalent 
level of, or only have a marginal impact on, safety?
    Most commenters believe that a move to performance-based 
regulations would uncover marginal requirements. Some believe that by 
conserving resources in areas where safety is not a significant issue, 
more resources can be devoted to more risk-significant areas with a net 
increase in the overall safety margin.
    6. Can the regulatory/safety objective (qualitative or 
quantitative) be established in an objective manner to allow a common 
understanding between licensees and the NRC on how the performance or 
results will be measured or judged?
    Several commenters believe that the regulatory process should 
integrate deterministic, risk-based, and performance-based regulation 
and allow for case-specific evaluation, with a goal of protecting the 
health and safety of the public and at the same time minimizing the 
cost to the licensee. Others believe that the opinions of public 
interest groups should also be sought in deriving safety goals/
objectives. Overall, no comments were presented that would suggest that 
a common understanding could not be achieved on goals and performance 
measurements.
    7. Can the regulation and implementation documents be developed in 
such a manner that they can be objectively and consistently inspected 
and enforced against?
    Several commenters believe that the regulations should be 
performance-based and the associated guidance documents should be 
prescriptive so that only the guidance documents not the regulations 
will need to be changed as more information is gained on compliance 
issues. Many commenters believe that PRAs should not be the sole basis 
for regulatory decisions due to the uncertainty in their results; 
however, if the results indicate that a particular requirement has a 
contribution to risk significantly below the Safety Goal thresholds, 
the PRA information should be considered sufficient to justify 
elimination of the requirement as marginal to safety.

Proposed Revision

    Based on several advance notices for rulemaking and significant 
public comment and discussion, risks and costs evaluated, and 
consideration of which modifications are feasible and practical at this 
time, the NRC proposes two phases for modifications of requirements to 
containment leakage testing. The first phase, for which modifications 
are proposed in this notice, will allow leak-rate testing intervals to 
be based on the performance of the containment system structures and 
components. The second phase will further examine the needed 
requirements of the containment function (i.e. structural and leak-
tight integrity of containment system structures and components, and 
prevention of inadvertent bypass), and include consideration of the 
potential of on-line monitoring of containment [[Page 9639]] integrity 
to verify certain functions. Solicitation of public comments to guide 
this future work is included later in this notice.
    The rule proposed in this notice would apply to all NRC licensees 
who operate light water power reactors. The proposed rule would allow 
licensees the option of continuing to comply with the current appendix 
J or to adopt the new performance-based standards.
    The NRC's analyses are based upon the insight gained through the 
use of probability risk assessment techniques and the significant data 
base of practical, hands-on operating experience gained since appendix 
J was promulgated in 1973. This operating experience provides hard 
evidence of the activities necessary to conduct appendix J testing, and 
the costs of those activities both in monetary terms and occupational 
radiation exposure.
    The results of the present effort documented in draft NUREG-1493, 
which are based on NUREG-1150, confirm previous observations of 
insensitivity of population risks from severe reactor accidents to 
containment leak-rates.
    The current appendix J requirements have achieved the regulatory 
criteria of assuring an essentially leak-tight boundary between the 
power reactor system and the external environment (GDC Criterion 16). 
Costs associated with complying with current appendix J requirements 
are estimated to be $165,000 for a complete battery of Type B/C tests 
and $1,890,000 for Type A tests. Over the average reactor's remaining 
lifetime of 20 years, the present value of all remaining leak testing 
at a five percent discount rate is about $7 million per reactor. 
Estimates of the remaining industry-wide costs of implementing current 
appendix J requirements range from $720 to $1,080 million, 
approximately 75 percent of which could be averted with a performance-
based rule.
    The present study found that by allowing requirements with marginal 
effect on safety, but which impose a significant cost on licensees, to 
remain in effect is to essentially misallocate a portion of the NRC's 
and the industry's resources on activities for which there is no 
commensurate return in safety. The real cost then may be in a missed 
opportunity to focus NRC and licensee efforts to areas where the return 
in terms of added public safety is higher.
    Specific alternatives for modifying the current appendix J were 
identified by the public in response to the NRC's Federal Register 
notice published on January 27, 1993 (58 FR 6196). Those whose 
characteristics matched the NRC's established criteria for the marginal 
to safety program were selected for further review.
Modifications of Initial Proposals

Allowable Leakage Rate

    The NRC had initially planned to establish, by rulemaking, a risk-
based allowable leak-rate commensurate with its significance to total 
public risk. Specific findings from draft NUREG-1493 on the allowable 
leakage rate include:
    1. Allowable leakage can be increased approximately two orders of 
magnitude (100-200 fold) with marginal impact on population dose 
estimates from reactor accidents.
    2. Calculated mean population risks are several orders of magnitude 
below the NRC's Safety Goals for all reactors considered, but the tail 
of the distribution can approach Safety Goals.
    3. Increases in the allowable leak-rate is estimated to have a 
negligible impact on occupational exposure.
    Relaxing the allowable leak-rate is estimated to reduce future 
industry testing costs by $50 to $110 million, a ten percent decrease 
in overall leak-rate testing costs.
    A risk-based allowable leakage rate would be based on an 
evaluation, using PRA, of the sensitivity and significance of 
containment leakage to risk, and determining an appropriate containment 
leakage limit commensurate with its significance to the risk to the 
public and plant control room operators. However, this would entail a 
major change in policy and restructuring of the current licensing basis 
and a more complete understanding of the uncertainties associated with 
the threat of severe accidents to the containment, and therefore, the 
NRC plans to consider a modification of the performance standard 
(allowable leakage level) in the second phase separate from 
modifications of testing requirements. This modification will be part 
of a broader effort to further examine the risk significance of various 
attributes of containment performance, i.e. structural and leak-tight 
integrity of containment system structures and components, and 
inadvertent bypass.

On-Line Monitoring (OLM) Systems

    Currently, there is no requirement for OLM systems which monitor 
the containment to detect unintentional breaches of containment 
integrity.
    Studies discussed in draft NUREG-1493, ``Performance-Based 
Containment Leak Test Program,'' find that, based on operating 
experience, OLM would not significantly reduce the risk to the public 
from nuclear plant operation and, thus, cannot be justified solely on 
risk-based considerations. Specific findings include:
    1. Continuous monitoring methods that exist appear technically 
capable of detecting leaks in reactor containments within 1 day to 
several weeks. OLM systems are in use or planned in several European 
countries.
    2. OLM systems are only capable of detecting leaks in systems that 
are open to the containment atmosphere during normal operation 
(approximately ten percent of the mechanical penetrations).
    3. The technical and administrative objectives of OLM systems and 
Type A tests are different.
    4. OLM cannot be considered as a complete replacement for Type A 
tests because it cannot challenge the structural and leak-tight 
integrity of the containment system at elevated pressures.
    5. Analysis of the history of operating experience indicates 
limited need for, and benefit of, OLM in the U.S.
    Although OLM cannot be justified solely based on risk 
considerations, a plant already possessing such a system has greater 
assurance of achieving certain attributes of containment integrity. 
Therefore, OLM systems could contribute towards an overall leakage 
monitoring scheme. Some capability for on-line monitoring already 
exists as a byproduct of specific containment designs. For example, 
licensees with inerted BWR containments, or subatmospheric PWR 
containments, would readily detect gross leakages that develop during 
normal operation.
    Given that the application of on-line monitoring is specific to 
containment design, and generic application cannot be justified solely 
on risk considerations, the NRC does not propose a requirement for 
OLMs. However, licensees which already have such a capability (e.g. 
inerted BWR containments, and subatmospheric PWR containments) are 
encouraged to propose plant-specific application of such a capability, 
including credit for any added assurance for certain attributes of 
containment integrity provided by such a system compared to other 
testing methods. The NRC will reconsider the role of OLM in the second 
phase of modifications in this area along with the allowable leakage 
rate.

Proposed Modification of Type A, B, C Test Intervals

    The NRC proposes at this time, for the first phase of 
modifications, to define a new risk-based regulation by utilizing the 
performance history of components [[Page 9640]] (containment, 
penetrations, valves) as the means to justify an increase in the 
testing interval for Type A, B, and C tests. The revised regulation 
would require tests to be conducted on an interval based on the 
performance of the containment structure, penetration or valves without 
specifying the interval in the regulation. Currently, three Type A 
tests are conducted in every 10 year period. Type B (except airlocks, 
which are tested more frequently) and C tests are conducted on a 
frequency not to exceed 2 years.
    The NRC proposes to base the frequency of Type A tests (ILRTs) on 
the historical performance of the overall containment system. Specific 
findings documented in draft NUREG-1493 that justify the proposal 
include:
    1. The fraction of leakages detected only by ILRTs is small, on the 
order of a few percent.
    2. Reducing the frequency of ILRT testing from three per 10 years 
to one per 10 years leads to a marginal increase in risk.
    3. ILRTs also test the strength of the containment structure. No 
alternative to ILRTs have been identified to provide assurance that the 
containment structure will meet allowable leakage rates during design-
basis accidents.
    4. At a frequency of one test per 10 years, industry-wide 
occupational exposure would be reduced by 0.087 person-sievert (8.7 
person-rem) per year.
    Based on specific, detailed analyses of data from the North Anna 
and Grand Gulf plants and data from twenty-two nuclear plants (see 
draft NUREG-1493), performance-based alternatives to current LLRT 
methods are feasible with marginal impact on risk. Specific findings 
that justify the proposal include:
    1. Type B and C tests detect a very large fraction, over 97 percent 
of containment leakages.
    2. Of the 97%, virtually all leakages are identified by LLRTs of 
containment isolation valves (Type C tests).
    3. Based on the detailed evaluation of the experience of a single 
2-unit station, no correlation of failures with type of valve or plant 
service could be found.
    4. For the 20 years of remaining operations, changing the Type B/C 
test frequency alone is estimated to reduce industry-wide occupational 
exposure by 0.72 person-sievert (72 person-rem) per year. If 20-year 
license extension is assumed, the estimate is 0.75 person-sievert (75 
person-rem) per year.
    Reducing the frequency of ILRTs will reduce future industry testing 
costs by approximately $330 to $660 million if tests are conducted once 
per 10 years versus the current three per ten years. These savings 
represent about 65 percent of the remaining costs of current appendix J 
requirements. Performance-based LLRT alternatives are estimated to 
reduce future industry testing costs by $40 million to $55 million. 
These savings represent about five percent of the total remaining costs 
of appendix J testing.
    Therefore, based on the risks and costs evaluated, and other 
considerations discussed above, a performance-based appendix J which 
encompasses the following principles which differ moderately from those 
first described in the Federal Register (January 27, 1993 58 FR 6197) 
is proposed:
    General. (1) Make appendix J less prescriptive and more 
performance- oriented; (2) Move details of appendix J tests to a 
regulatory guide as guidance; (3) Endorse approved industry guideline 
(NEI 94-01) on guidance on the conduct of containment tests in a 
regulatory guide. The methods for testing are contained in an industry 
standard (ANSI/ANS 56.8-1994) which is referenced in the NEI guideline; 
(4) Allow voluntary adoption of the new regulation, i.e., current 
detailed requirements in appendix J will continue to be acceptable for 
compliance with the modified rule.
    Leakage Limits. Acknowledge the less risk-significant nature of 
allowable containment leakage (L<INF>a) but pursue its modification as 
a separate action.
    Type A Test Interval. (1) Based on the limited value of integrated 
leak-rate tests (ILRTs) in detecting significant leakages from 
penetrations and isolation valves, establish the test interval based on 
the performance of the containment system structure; (2) The 
performance criterion of the test will continue to be the allowable 
leakage rate (La); (3) The industry guideline allows extension of the 
Type A test interval to once every 10 years based on satisfactory 
performance of two previous tests; (4) In the regulatory guide, the NRC 
has included an exception for the extension of the interval of the 
general visual inspection of the containment system, and limited the 
interval to three times every 10 years as is current practice.
    Type B & C Test Interval. (1) Allow local leak-rate test (LLRTs) 
intervals to be established based on the experience history of each 
component; (2) The performance criterion for the tests will continue to 
be the allowable leakage rate (La); (3) Specific performance criteria 
and factors for establishing extended test intervals (up to 10 years 
for Type B components, and 5 years for Type C components) are contained 
in the regulatory guide and industry guideline. In the regulatory 
guide, the NRC has included an exception to the extension of Type C 
test intervals up to 10 years that is proposed in the NEI industry 
guideline, and limited such extensions to 5-years.
Specific Areas for Public Comment

    In its preliminary criteria for developing performance-based 
regulations, the NRC identified three issues to be addressed by the 
rulemaking process as a measure of the viability of the revised rule. 
These issues have been addressed in the rulemaking package and the NRC 
is seeking further public input on them.
    1. Can the new rule and its implementation yield an equivalent 
level of, or would it only have a marginal impact on, safety?
    The present study analyzed risks to the population and to workers 
from changes in appendix J requirements. The results of the present 
analysis confirm that population risks from severe reactor accidents 
are not sensitive to containment leak-rates. The calculated risks are 
well below the Safety Goals for all of the reactors considered even at 
assumed containment leak-rates 100-fold above current requirements. A 
change in the allowable leak-rate is estimated to have a negligible 
impact on occupational exposure. Results also show that relaxing the 
frequency of Type A, B, and C tests leads to an increase in overall 
reactor risk of approximately two percent. This increase is considered 
to be marginal to safety. Due to limitations of available plant data, 
the uncertainties of the risk impact of extending Type C test intervals 
beyond sixty months needs to be addressed.
    Costs associated with complying with current appendix J 
requirements are estimated to be $165,000 for a complete battery of 
Type B/C tests, and $1,890,000 for Type A tests. Over the average 
remaining lifetime of 20 years, the present value of all remaining leak 
testing is about $7 million per reactor at a five percent discount 
rate. The estimates of remaining industry-wide costs to comply with the 
requirements of the current appendix J are approximately $720 to $1,080 
million at a five percent discount rate, over 75 percent of which could 
be averted with a risk-based rule.
    Based on the results of the present study, the NRC concludes that 
its safety objective for containment integrity can be maintained while 
at the same time reducing the burden on licensees. Thus, the new rule 
and its implementation can yield an equivalent level of, or only have a 
marginal impact on, safety. [[Page 9641]] 
    2. Can the regulatory/safety objective (qualitative or 
quantitative) be established in an objective manner to allow a common 
understanding between licensees and the NRC on how the performance or 
results will be measured or judged?
    Conformance to the new appendix J requirements will be measured by 
the adequacy of the methods for establishing the frequency of Type A, B 
and C testing. It is a fundamental principle of this rulemaking that 
changes to existing leak-test requirements be based objectively upon 
the performance history of components as analyzed by established 
methods.
    To assist in the common understanding of new methods of 
establishing Type A, B and C test frequencies between the NRC and power 
reactor licensees, the NRC has had ongoing discussions with licensees. 
These discussions included participation in workshops designed to 
elicit a common understanding. From these efforts, the NRC is proposing 
to endorse a guidance document from industry which specifies acceptable 
methods for achieving compliance with Appendix J.
    Further, the NRC proposes to require that plant technical 
specifications provide a general reference to the regulatory guide or 
other implementation document to ensure the prior review and approval 
by the NRC of licensee deviations from approved methods. This will help 
maintain a common understanding in the implementation of the 
performance-based rule, and ensure adequate basis for licensee 
deviations.
    The NRC expects that its activities to date, the review and 
endorsement of a industry guideline in a regulatory guide, and the 
general reference of the regulatory guide in plant technical 
specifications, will establish regulatory safety objectives in an 
objective manner, and provide a common understanding on the measures of 
compliance.
    3. Can the regulation and implementation documents be developed in 
such a manner that they can be objectively and consistently inspected 
and enforced against?
    A guidance document developed by industry and approved for use by 
the NRC helps to ensure consistent interpretation and application of 
compliance requirements. As experience is gained under the new rule, 
adjustments may be reasonably anticipated to the industry's guidance 
document which will be reviewed and approved by the NRC through the 
regulatory guide revision process. The NRC's regulatory and inspection 
personnel shall be trained in the interpretation and use of all 
relevant implementation documents to assure consistent enforcement.
    In addition to the above, the NRC solicits comments on the 
following two issues.
    4. Should the proposed revision be made even less prescriptive?
    The proposed rule is less prescriptive than existing requirements 
and provides licensees with greater flexibility in the implementation 
of safety objectives established by NRC. This action is proposed based 
on substantive technical analyses presented in draft NUREG-1493. 
Regulatory positions were developed by the NRC through insights from 
probabilistic risk analyses, operating data, and deterministic 
engineering considerations. The NRC solicits public comment on whether 
this revision should make the rule even less prescriptive than proposed 
in this notice; and if so, how?
    Specifically, comments are solicited on the potential alternative 
of further relaxing the test frequency requirements for the Integrated 
Leak Rate Tests (ILRT) by establishing a fixed ten-year interval based 
on generic industry data, or perhaps eliminating the tests beyond the 
first pre-operational test. Analyses of historical test data and risk 
analyses presented in draft NUREG-1493 indicate that the ILRT interval 
could be extended beyond the proposed ten-year interval, and perhaps 
eliminated after the first pre-operational test with marginal impact on 
safety. Leakages detected by an ILRT are rare and random, and not 
generally related to previous performance at a plant. However, the NRC 
considers that a ten-year testing interval, based on satisfactory 
previous plant-specific performance, is appropriate at this time. It is 
consistent with current industry practice for testing of pressure 
vessels, and should detect the potential for aging mechanisms that 
could affect containment leaktightness. Historical test data have not 
yet shown evidence of such aging mechanisms but they might develop late 
in life where little data exists. Comments are solicited on other 
benefits provided by the ILRT, in addition to determining the leakage 
rate, that would need to be addressed to justify further relaxations or 
elimination of the test. NRC's current position is guided by the desire 
to maintain some conservatism to address uncertainties and adopt an 
evolutionary approach in the modification of its requirements. However, 
the NRC does not wish to maintain undue conservatism in its 
regulations, and therefore, will consider comments received to 
determine the degree of prescriptiveness, and any further relaxation of 
the ILRT requirements included in the final rule.
    5. Should the proposed revisions be made mandatory?
    The NRC is considering whether the proposed rule, which as 
currently proposed would provide licensees with a non-mandatory 
alternative to their existing appendix J containment leak testing 
program, should instead be adopted as a mandatory requirement for all 
licensees.
    The proposed rule is drafted as a non-mandatory alternative to 
current appendix J requirements because the Staff recognized that some 
licensees may have technical programs which they may not wish to modify 
at this time, even though a proposed modification would constitute a 
``relaxation'' from current requirements or provide other regulatory or 
economic benefit. For these reasons, the Commission earlier approved a 
Staff policy whereby any proposed revisions to existing NRC 
requirements developed by the Regulatory Improvement Program (See SECY-
94-090, ``Institutionalization of Continuing Program for Regulatory 
Improvement,'' March 31, 1994) would not be mandatory, but would be 
proposed as alternatives (options) to existing requirements which may 
be voluntarily adopted by licensees. Given the history of difficulty 
and low success rate for attempts to resolve new safety issues 
simultaneously with improvements to regulatory efficiency, the 
Commission also approved a Staff policy for separating regulatory 
actions for new safety issues from those for improving regulatory 
efficiency. Therefore, this proposed rule does not address any new 
safety issues beyond the scope of the current appendix J requirements 
and is not aimed at improving safety.
    The NRC is interested in the public's view as to whether the 
proposed rule should be made mandatory, in light of the overall long-
term reduction in regulatory burden on licensees and the marginal 
impact on safety which would be entailed in the relaxation (see 
previous discussion in ``Proposed Modification of Type A, B, C Test 
Intervals). The NRC is interested in the public's views on using the 
increase in regulatory efficiency as a potential rationale for making 
the proposed rule mandatory for all licensees. The NRC also requests 
public comment on the underlying policy discussed above that NRC 
rulemakings which are not intended to increase safety, but are only 
intended to increase regulatory efficiency and reduce the regulatory 
burden imposed by the NRC's rules, [[Page 9642]] should be adopted as 
alternatives to existing requirements which may be voluntarily adopted 
by the regulated entity.
    The NRC recognizes that if the proposed rule were made mandatory, 
that several backfitting issues are raised. These backfitting concerns 
are discussed in more detail in the next section on the ``Backfit 
Rule.''
Backfit Rule

    As discussed above, the Commission is considering whether the 
proposed rule, which is currently drafted as providing licensees with a 
non-mandatory alternative relaxing the requirements for and frequency 
of containment leakage testing, should be adopted as a mandatory 
requirement (that is, the requirements of the rule would be imposed on 
all nuclear power plant licensees). If the alternative is made 
mandatory, the Commission acknowledges the potential relevance of the 
Backfit Rule. The Commission believes that the Backfit Rule was 
intended to constrain the Commission's adoption of mandatory 
relaxations of Commission requirements, if the mandated change imposed 
costs upon the licensee and that such mandatory relaxations are 
``backfits'' as defined in Sec. 50.109(a)(1). However, the Commission 
believes that it has the authority and basis for ``waiving'' the 
application of the Backfit Rule to the adoption of this rulemaking. The 
Commission requests public comments on each of these points.

1. The Proposed Rule Constitutes a ``Backfit''

    The current version of the Backfit Rule, 10 CFR 50.109, was adopted 
in substantially its current form in 1985.<SUP>5 50 FR 38097 (September 
20, 1985). Based upon a review of the rulemaking record which led to 
the final 1985 rule, the Commission's objective in adopting the Backfit 
Rule was to prevent the imposition of new requirements, not otherwise 
needed to assure adequate protection or compliance, which were of 
marginal overall safety benefit or involved implementation costs which 
were out of proportion to the safety benefits. The SOC explained that 
under the new backfitting standard ``the Commission would not 
ordinarily expect that safety improvements would be required as 
backfits which result in an insignificant or small benefit to the 
public health and safety or common defense and security, regardless of 
the implementation costs'' (50 FR at 38102). Thus, the aim of the 
Backfit Rule was to instill into the regulatory process the need for 
disciplined analysis of proposed new requirements and regulatory 
initiatives (See generally 50 FR at 38101-38102).

    \5\The Backfit Rule was subsequently amended in 1988 (53 FR 
20603, June 6, 1988) in response to a decision of the U.S. Court of 
Appeals for the D.C. Circuit Union of Concerned Scientists et al. v. 
U.S. Nuclear Regulatory Commission, 824 F.2d 103) which remanded the 
1985 rule to the NRC because the rule failed to clearly indicate 
that costs may not be a consideration in determining whether there 
is adequate protection to the public health and safety.
---------------------------------------------------------------------------

    The proposed revision relaxes and modifies existing requirements 
where the Commission believes that the burdens are not commensurate 
with their safety significance. Furthermore, the proposed rule does not 
contain any new requirements to address new safety issues not addressed 
in the original Appendix J rulemaking. However, if imposed as a 
mandatory requirement the proposed rule would mandate changes in a 
licensee's program for conducting containment leak rate tests, and 
would impose short-term costs on the licensee in order to reduce the 
long-term regulatory burden. However desirable such an imposition may 
be over the long term, it would nonetheless constitute a ``backfit'' as 
defined in Sec. 50.109(a)(1). However, the Commission requests public 
comment on whether the definition of ``backfit'' in Sec. 50.109(a)(1) 
was intended to encompass rulemakings of the type represented by this 
proposed rule.

2. Waiving the Applicability of the Backfit Rule

    The Commission adopted the Backfit Rule as a self-imposed 
limitation on its rulemaking authority, and under the appropriate 
circumstances the Commission may ``waive'' its applicability, subject 
to the Administrative Procedure Act's requirement in rulemaking for 
notice and opportunity for public comment. The Commission believes that 
it is appropriate to ``waive'' the applicability of the Backfit Rule to 
the proposed rule if its requirements were made mandatory. The purpose 
of the rule is to relax and modify existing containment leak rate 
testing requirements where burdens are not commensurate with their 
safety significance. It does not contain any new requirements to 
address new safety issues not addressed in the original appendix J 
rulemaking. The proposed revision would relax existing marginal-to-
safety requirements in order to reduce regulatory burden on nuclear 
power plant licensees and increase regulatory efficiency. This type of 
rulemaking complements the objectives of the Backfit Rule by 
eliminating requirements with little or no positive impact on safety, 
but whose regulatory burden is substantial. Therefore, if the 
Commission determines to impose the proposed rule's requirements, the 
Commission proposes to ``waive'' this rule from the requirements of the 
Backfit Rule.
    The Commission requests public comment on the proposed rationale 
for ``waiving'' the application of the Backfit Rule to this rulemaking.

Regulatory Guide; Issuance, Availability

    A draft regulatory guide, temporarily identified by its task number 
DG-1037, (on the same subject) ``Performance-Based Containment Leak-
Test Program'' is also being published for comment. The regulatory 
guide endorses an industry standard which contains guidance on an 
acceptable performance-based leak-test program, leakage rate test 
methods, procedures, and analyses that may be used to implement these 
requirements and criteria.
    This draft guide is being issued to involve the public in the early 
stages of the development of a regulatory position in this area. It has 
not received complete staff review and does not represent an official 
NRC staff position.
    Public comments are being solicited on the draft guide. Comments 
should be accompanied by supporting data. Specific comments are 
solicited on whether the regulatory guide and the industry guideline it 
endorses will result in a common understanding between licensees and 
the NRC on how performance will be measured and judged, and can be 
objectively inspected against. Written comments may be submitted to the 
Rules Review and Directives Branch, Division of Freedom of Information 
and Publications Services, Office of Administration, U.S. Nuclear 
Regulatory Commission, Washington, DC 20555. Comments will be most 
helpful if received by May 8, 1995. Comments on the draft regulatory 
guide may be submitted electronically as indicated elsewhere under the 
ADDRESSES heading.
    Although a time limit is given for comments on these drafts, 
comments and suggestions in connection with (1) items for inclusion in 
guides currently being developed or (2) improvements in all published 
guides are encouraged at any time.
    Regulatory guides are available for inspection at the Commission's 
Public Document Room, 2120 L Street NW., Washington, DC. Requests for 
single copies of draft guides (which may be reproduced and are 
available free to the extent of supply) or for placement on an 
automatic distribution list for single copies of future draft guides in 
specific [[Page 9643]] divisions should be made in writing to the 
Office of Administration, Printing and Mail Services Section, U.S. 
Nuclear Regulatory Commission, Washington, DC 20555-0001. Telephone 
requests cannot be accommodated. Regulatory guides are not copyrighted, 
and Commission approval is not required to reproduce them. The draft 
regulatory guide may also be viewed and downloaded electronically via 
the Electronic Bulletin Board established by NRC for this rulemaking.

Implementation

    The proposed Option B to Appendix J specifies that the rule will 
become effective 30 days after publication. At any time thereafter, a 
licensee or applicant would notify the NRC of its desire to perform 
containment leakage rate testing according to Option B. Accompanying 
this notification, a licensee would submit proposed technical 
specifications changes which would eliminate those technical 
specifications which implement the current rule and propose a new 
technical specification referencing the NRC regulatory guide or, if the 
licensee desires, an alternative implementation guidance. 
Implementation must await staff review and approval of the licensee's 
proposal. The staff anticipates that a generic communication will be 
issued which will provide the implementation procedure to all power 
reactor licensees.

Solicitation of Comments for Future Revisions

    As indicated earlier in this notice, the NRC plans a second phase 
of modifications to requirements for containment leakage rate testing 
to further adopt risk-based methods, and to broadly examine the type of 
performance-based rule needed to ensure the adequacy of the containment 
function. This will include increasing the allowable leakage rate based 
on risk considerations, further examination of the risk significance of 
various attributes of containment performance (structural and leaktight 
integrity of containment structures and components, and inadvertent 
bypass), and consideration of the potential of on-line monitoring of 
containment integrity to address certain attributes. In order to guide 
this future effort, the NRC has formulated the following questions and 
solicits public comments on them:
    1. Should NRC pursue a fundamental modification of its regulations 
in this area by establishing an allowable leakage rate based on risk 
analysis (as presented in draft NUREG-1493, Chapter 5), as compared to 
the current practice of using deterministic design basis accidents and 
dose guidelines contained in 10 CFR part 100; or should the NRC modify 
the allowable leakage rate within the current licensing basis by 
revising source terms and updating regulatory guides (R.G.s 1.3 and 
1.4)<SUP>6 for calculating doses to the public? What are the advantages 
and disadvantages of the two approaches? What are some other 
considerations than risk to public, e.g. plant control room 
habitability, that might limit the allowable leakage rate?

    \6\Copies may be purchased at current rates from the 
Superintendent of Documents, U. S. Government Printing Office, Mail 
Stop SSOP, Washington, DC 20402-9328 (telephone 202 512-2249 or 202 
512-2171); or from the National Technical Information Service by 
writing NTIS at Port Royal Road, Springfield, VA 22161.
---------------------------------------------------------------------------

    2. If the allowable leakage rate is increased, could on-line 
monitoring of containment integrity replace other current containment 
tests? Could the results of the on-line monitoring be used to establish 
a new performance basis for containment integrity involving less 
stringent reporting requirements if there is high assurance there are 
no large leakage paths in containment (> 1 in. diameter).
    3. Are there any other regulatory approaches and technical methods 
by which the NRC can adopt a complete performance and risk basis to its 
regulations for containment leaktight integrity? What are some of the 
attributes for performance, and what risk-based methods can be used to 
analyze these attributes?

Finding of No Significant Environmental Impact: Availability

    The Commission has determined under the National Environmental 
Policy Act of 1969, as amended, and the Commission's regulations in 
subpart A of 10 CFR part 51, that this rule, if adopted, would not be a 
major Federal action significantly affecting the quality of the human 
environment, and therefore an environmental impact statement is not 
required. There will be no radiological environmental impact offsite, 
and the occupational exposure onsite is expected to decrease by about 
0.8 person rem per year of plant operation for plant personnel if 
licensees adopt the performance-based testing scheme provided in the 
revised regulation. Alternatives to issuing this revision of the 
regulation were considered and found not acceptable. Single copies of 
the environmental assessment and finding of no significant impact can 
be obtained by submitting a written request to: Dr. Moni Dey, U.S. 
Nuclear Regulatory Commission, Washington, DC 20555.

Paperwork Reduction Act Statement

    This proposed rule amends information collection requirements that 
are subject to the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et 
seq.). This rule has been submitted to the Office of Management and 
Budget for review and approval of the paperwork requirements.
    Because the rule will relax existing information collection 
requirements by providing an option to the existing requirements, the 
public burden for this collection of information is expected to be 
reduced by as much as 4583 hours per year, including the time required 
for reviewing instructions, searching existing data sources, gathering 
and maintaining the data needed and completing and reviewing the 
collection of information. Send comments regarding the estimated burden 
reduction or any other aspect of this collection of information to the 
Information and Records Management Branch, T-6F33, U.S. Nuclear 
Regulatory Commission, Washington, DC 20555-0001; and to the Desk 
Officer, Office of Information and Regulatory Affairs, NEOB-10202, 
(3150-0011), Office of Management and Budget, Washington, DC 20503.
Regulatory Analysis

    The Commission has prepared a draft regulatory analysis on this 
proposed regulation. The analysis examines the costs and benefits of 
the alternatives considered by the Commission. The draft analysis is 
available for inspection or copying for a fee in the NRC Public 
Document Room, 2120 L Street NW (Lower Level), Washington, DC; the 
PDR's mailing address is Mail Stop LL-6, Washington, DC 20555; phone 
(202) 634-3273; fax (202) 634-3343.
    The Commission requests public comment on the draft analysis. 
Comments on the draft analysis may be submitted to the NRC as indicated 
under the ADDRESSES heading.

Regulatory Flexibility Certification

    In accordance with the Regulatory Flexibility Act of 1980, (5 
U.S.C. 605(b)), the Commission certifies that this rule will not, if 
promulgated, have a significant economic impact on a substantial number 
of small entities. This proposed rule affects only the licensing and 
operation of nuclear power plants. The companies that own these plants 
do not fall within the scope of the definition of ``small entities'' 
set forth in the Regulatory Flexibility Act or the Small Business Size 
Standards set [[Page 9644]] out in regulations issued by the Small 
Business Administration in 13 CFR part 121.

Backfit Analysis

    This proposed revision to a current regulation by the inclusion of 
an option that may be voluntarily adopted by licensees, and which 
relaxes current requirements, is not considered a backfit under 10 CFR 
50.109(a). Therefore, a backfit analysis is not necessary.

List of Subjects in 10 CFR Part 50

    Antitrust, Classified information, Criminal penalties, Fire 
protection, Incorporation by reference, Intergovernmental relations, 
Nuclear power plants and reactors, Radiation protection, Reactor siting 
criteria, Reporting and recordkeeping requirements.

    For the reasons set out in the preamble and under the authority of 
the Atomic Energy Act of 1954, as amended, the Energy Reorganization 
Act of 1974, as amended, and 5 U.S.C. 553, the NRC is proposing to 
adopt the following amendments to 10 CFR part 50.

PART 50--DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION 
FACILITIES

    1. The authority citation for Part 50 is revised to read as 
follows:

    Authority: Secs. 102, 103, 104, 105, 161, 182, 183, 186, 189, 68 
Stat. 936, 937, 938, 948, 953, 954, 955, 956, as amended, sec. 234, 
83 Stat. 1244, as amended (42 U.S.C. 2132, 2133, 2134, 2135, 2201, 
2232, 2233, 2236, 2239, 2282); secs. 201, as amended, 202, 206, 88 
Stat. 1242, as amended, 1244 1246 (42 U.S.C. 5841, 5842, 5846).

    Section 50.7 also issued under Pub. L. 95-601, sec. 10, 92 Stat. 
2951, as amended by Pub. L. 102-486, sec. 2902, 106 Stat. 3123, (42 
U.S.C. 5851). Sections 50.10 also issued under secs. 101, 185, 68 
Stat. 936, 955, as amended (42 U.S.C. 2131, 2235); sec. 102, Pub. L. 
91-190, 83 Stat. 853 (42 U.S.C. 4332). Sections 50.13, 50.54(dd), 
and 50.103 also issued under sec. 108, 68 Stat. 939, as amended (42 
U.S.C. 2138). Sections 50.23, 50.35, 50.55, and 50.56 also issued 
under sec. 185, 68 Stat. 955 (42 U.S.C. 2235). Sections 50.33a, 
50.55a and Appendix Q also issued under sec. 102, Pub. L. 91-190, 83 
Stat. 853 (42 U.S.C. 4332). Sections 50.34 and 50.54 also issued 
under sec. 204, 88 Stat. 1245 (42 U.S.C. 5844). Sections 50.58, 
50.91, and 50.92 also issued under Pub. L. 97-415, 96 Stat. 2073 (42 
U.S.C. 2239). Section 50.78 also issued under sec. 122, 68 Stat. 939 
(42 U.S.C. 2152). Sections 50.80-50.81 also issued under sec. 184, 
68 Stat. 954, as amended (42 U.S.C. 2234). Appendix F also issued 
under sec. 187, 68 Stat. 955 (42 U.S.C. 2237).

    2. Appendix J to 10 CFR Part 50 is amended by adding the following 
language between the heading and the Table of Contents and adding the 
language for Option B after Section V.B3.

Appendix J--Primary Reactor Containment Leakage Testing for Water-
Cooled Power Reactors.

    This appendix includes two options, A and B, either of which can 
be chosen for meeting the requirements of this appendix.

Options A--Prescriptive Requirements

* * * * *
Option B--Performance-Based Requirements

Table of Contents

I. Introduction.
II. Definitions.
III. Performance-based leakage test requirements.
    A. Type A test.
    B. Type B and C tests.
IV. Recordkeeping.
V. Implementation.

I. Introduction

    One of the conditions required of all operating licenses for 
light-water-cooled power reactors as specified in Sec. 50.54(o) is 
that primary reactor containments meet the leakage rate test 
requirements in either Option A or B of this appendix. These test 
requirements ensure that (a) leakage through these containments or 
systems and components penetrating these containments does not 
exceed allowable leakage rates specified in the Technical 
Specifications and (b) integrity of the containment structure is 
maintained during its service life. Option B of this appendix 
identifies the performance-based requirements and acceptance 
criteria for preoperational and subsequent periodic leakage rate 
testing.<SUP>7

    \7\Specific guidance concerning a performance-based leak test 
program, acceptable leakage rate test methods, procedures, and 
analyses that may be used to implement these requirements and 
criteria are provided in draft Regulatory Guide DG-1037, 
``Performance-Based Containment System Leakage Testing.''
---------------------------------------------------------------------------

II. Definitions

    Acceptance criteria means the performance standards against 
which test results are to be compared for establishing the 
acceptability of the containment system as a leakage limiting 
boundary.
    Containment system means the principal barrier, after the 
reactor coolant pressure boundary, to prevent the release of 
quantities of radioactive material that would have a significant 
radiological effect on the health of the public.
    Overall integrated leakage rate means the total leakage rate 
through all tested leakage paths, including containment welds, 
valves, fittings, and components that penetrate the containment 
system.
    La (percent/24 hours) means the maximum allowable leakage rate 
at pressure Pa as specified in the Technical Specifications.
    Pa (p.s.i.g) means the calculated peak containment internal 
pressure related to the design basis loss-of-coolant accident as 
specified in the Technical Specifications.

III. Performance-Based Leakage Test Requirements

A. Type A Test

    Type A tests to measure the containment system overall 
integrated leakage rate must be conducted under conditions 
representing design basis loss-of-coolant accident containment peak 
pressure. A Type A test must be conducted (1) after the containment 
system has been completed and is ready for operation and (2) at a 
periodic interval based on the historical performance of the overall 
containment system as a barrier to fission product releases to 
reduce the risk from reactor accidents. A general visual inspection 
of the accessible interior and exterior surfaces of the containment 
system for structural deterioration which may affect the containment 
leaktight integrity must be conducted prior to each test, and at a 
periodic interval between tests based on the performance of the 
containment system. The leakage rate must not exceed the allowable 
leakage rate (La) with margin as specified in the Technical 
Specifications. The test results must be compared with previous 
results to examine the performance history of the overall 
containment system to limit leakage.

B. Type B and C Tests

    Type B pneumatic tests to detect and measure local leakage rates 
across pressure retaining, leakage limiting boundaries, and Type C 
pneumatic tests to measure containment isolation valve leakage 
rates, must be conducted (a) prior to initial criticality, and (b) 
periodically thereafter at intervals based on the safety 
significance and historical performance of each boundary and 
isolation valve to ensure the integrity of the overall containment 
system as a barrier to fission product release to reduce the risk 
from reactor accidents. The performance-based testing program must 
contain performance goals and acceptance criteria, consideration of 
factors that affect performance when establishing test intervals, 
evaluations of performance of containment system components, and 
comparison to previous test results to examine the performance 
history of the overall containment system to limit leakage. The 
tests must demonstrate that (1) the sum of the leakage rates at 
accident pressure of Type B tests, and pathway leakage rates from 
Type C tests, is less than the total allowable leakage rate (La) 
specified in the Technical Specification with margin; and (2) the 
performance goal for the reliability of the overall containment 
system to limit leakage during reactor accidents is not exceeded.

IV. Recordkeeping

    The results of the preoperational and periodic Type A, B, and C 
tests must be documented to show that acceptance criteria for 
leakage have been met. The comparison to previous results of the 
performance of the overall containment system and of individual 
components within it must be documented to show that the test 
intervals established for the containment system and components 
within it are adequate. These records must be available for 
inspection at plant sites.
    If any Type A, B, or C tests fail to meet their leakage rate 
acceptance criteria as [[Page 9645]] defined in the plant Technical 
Specifications those failures must be assessed for Emergency 
Notification System reporting under Secs. 50.72(b)(1)(ii) and 
50.72(b)(2)(i), and for a Licensee Event Report under 
Secs. 50.73(a)(2)(ii).
V. Implementation

A. Applicability

    The requirements in either or both Option B, III.A for Type A 
tests, and Option B, III.B for Type B and C tests, may be adopted on 
a voluntary basis by an operating nuclear power reactor licensee as 
specified in Sec. 50.54 in substitution of the requirements for 
those tests contained in Option A of this appendix. If the 
requirements for tests in Option B, III.A or Option B, III.B are 
implemented, the recordkeeping requirements in Option B, IV for 
these tests must be substituted for the reporting requirements of 
these tests contained in Option A of this appendix.

B. Effective Date

    1. Specific exemptions to Option A of this appendix that have 
been formally approved by the AEC or NRC, according to 10 CFR 50.12, 
are still applicable to Option B of this appendix if necessary, 
unless specifically revoked by the NRC.
    2. This amendment to this appendix, by inclusion of an 
additional option for meeting the requirements of the appendix, is 
effective (30 days after the publication of the final rule). At any 
time hereafter a licensee or applicant for an operating license can 
adopt Option B, or parts thereof, as specified in Section V.A of 
this appendix, by submitting a notification of its implementation 
plan and request for revision to technical specifications to the 
Director of the Office of Nuclear Reactor Regulation.
    The regulatory guide or other implementation document used by a 
licensee, or applicant for an operating license, to develop a 
performance-based leakage testing program must be included, by 
general reference, in the plant's technical specifications. The 
detailed licensee programs must be available at the plant site for 
inspection thereafter. The programs must contain justification, 
including supporting analyses, if they deviate from methods approved 
by the Commission and endorsed in a regulatory guide. The deviations 
and their justifications must be described in the notification 
provided by the licensee of its implementation plan and the 
submittal for revision of plant technical specifications.

     Dated at Rockville, MD, this 14th day of February, 1995.

    For the Nuclear Regulatory Commission.
John C. Hoyle,
Acting Secretary of the Commission.
[FR Doc. 95-4167 Filed 2-17-95; 8:45 am]
BILLING CODE 7590-01-P

</pre><script data-cfasync="false" src="/cdn-cgi/scripts/5c5dd728/cloudflare-static/email-decode.min.js"></script></body>
</html>