ML20206F159

Requests That CRGR Review & Endorse Encl Commission Paper & Attachments.Ogc Reviewed Package & Has No Legal Objections

ML20206F159
Person / Time
Issue date:	04/09/1999
From:	Zimmerman R NRC (Affiliation Not Assigned)
To:	Jerome Murphy Committee To Review Generic Requirements
Shared Package
ML20206F150	List: ML20206F148 ML20206F159 ML20206F165
References
NUDOCS 9905060012
Download: ML20206F159 (55)

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t.S FIC fj 4 UNITED STATES F e e S NUCLEAR REGULATORY COMMISSION E WASHINGTON, D.C. 20 % 0001 n E April 9, 1999

. 'k . . . . . o MEMORANDUM TO:-Joseph A: Murphy, Chairman

Committee To Review Generic Requirements FROM

Roy Zimmerman, Deputy Director <1 ,

Office of Nuclear Reactor Regulation ' /

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SUBJECT:

REQUEST FOR REVIEW AND ENDO NT OF THE PROPOSED

FINAL RULEMAKING TITLED " FINAL REVISION TO 10 CFR 50.65 TO REQUIRE LICENSEES TO PERFORM PRE-MAINTENANCE

! ASSESSMENTS l .. . ---

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1 NRR has completed the final evision to 10 CFR 50.65, Requirements for Monitoring the j Effectiveness of Maintenance (the maintenance rule). The rule is amended to require that.

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before performing maintenance, licensees assess and manage the increases in risk that may result from the maintenance activities. NRR requests that CRGR review and endorse the attached commission paper and its attachments.

The completed rulemaking package (enclosure 1) included for your review contains the following documents: 1) Commission paper,2) Federal Register notice,3) Regulatory and

[ Backfit Analyses, 4) Congressional letters 5) Public announcement, and 6) Congressional Review Act forms.

To assist in your review please note that the Regulatory Analysis included in the rulemaking package conforms to the directives and guidance of NUREG\BR-0058,' Regulatory Analysis Guidelines of the U. S. Nuclear Regulatory Commission," and contains the information and analyses that meet the requirements of both 10CFR 50.109, the Backfit Rule, and provisions of the Revised Charter for the Committee to Review Generic Requirements (CRGR), Revision 6, dated April 1996.

[ For the committee's information, NRR has also included a preliminary draft regulatory guide -

(enclosure 2) that describes an acceptable method for licensees to use for performing pre-maintenance safety assessments. This regulatory guide will be published for public comment prior to the effective date of the amendment to 10 CFR 50.65. NRR is not asking for CRGR

[ concurrence on the preliminary draft regulatory guide at this time, since it is stillin a i developmental stage.

The Office of the General Counsel (OGC) reviewed this package and has no legal objections.

9905060012 990430 PDR COMMS NRCC CORRESPONDENCE PDR ~- ~ - ~ ~ ~ ~ ~ ~ ~ ~

Attacnments: As stated e CONTACT: Richard Correia, NRR ~

- -ATTACHMENT 1 (301)415-1009

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Wayne Scott, NRR F

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The Commissioners EQB:

FROM:

Wdliam D. Travers ..

Executive Director for Operation >

SUBJECT:

FINAL REVISION TO 10 CFR 50.65 TO REQUIRE 1.l PERFORM ASSESSMENTS BEFORE . PERFORMING .. .. ..

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} _P_ URPOSE:

To obtain the Commission's appros 91 to publish a final rule in the_ F 10 CFR 50.65 to require that, before performing maintenance, licensees as

the increase in risk that may result from the maintenance activities. .

$ BACKGROUND:

i On December 17,1997, the Commission issued was on the paragraph (a)(3) recommendation: "In performing monitoring maintenance activities, an assessment of the total plant equipment th t be taken into account to determine the overall effect on performance o principal purpose of the amendment is to require licensees to pe 1

manage the increase in plant risk that may result from the maintenan 1998, the staff presented its proposed revision to the rule in SECY-1998, the Commission issued SRM-98-165 approving publication of th

Federal Reaister for a 75-day comment period (63 FR 52201; September

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comment period ended December 14,1998. .

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CONTACT: -

' Richard Correia, NRR ~

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301-415-1009 7 I Harry Tovmassian, NRR 1:.z.

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] DISCUSSION:

i i The proposed revision to the maintenance rule to require that licensees perform assessments

_and use the results to manage.the increase in risk due to maintenance activities has been_ . _ _ _ . .

'. modified in response to public comments. Comments were received from 34 sources: 26 ~

utilities with operating units,3 nuclear industry service companies or consultants, a utility with a single unit in decommissioning status, an individual, a State agency, a law firm representing

.l several utilities, and the Nuclear Energy Institute (NEI), whose comments were supported by 29 respondents. The details of the comments and responses are incorporated in the final Federal Reaister notice (Attachment 1). ,

Nearly all respondents were concemed with the wording of paragraph (a)(4) of the proposed i rule. The proposed paragraph (a)(4) read:

• Before performing maintenance activities on structures, systems or components within the scope of this section (including but not limited to, surveillance testing, i post-maintenance testing, corrective maintenance, performance / condition mnnitoring, and preventive maintenance), an assessment of the current plant configuration as well as expected changes to plant configuration that will result from the proposed maintenance activities shall be conducted to determine the overall effect on performance of safety functions. The results of this assessment shall be used to ensure that the plant

. is not placed in risk significant configurations or configurations that would degrade the performance of safety functions to an unacceptable level."

Paragraph (a)(4) as revised after consideration of public comments reads:

"Before performing maintenance activities (including but not limited to surveillances, post-maintenance testing, and corrective and preventive maintenance) on structures, systems, or components within the scope of this section, the licensee shall assess and manage the increase in risk that may result from the proposed maintenance activities."

In its comments, NEl stated that "this rulemaking represents a significant new requirement," and -

NEl provided three specific concerns about the rule. The first NEl concem addressed terminology and stated that terms such as

• risk-significant configuration

• and " configurations that would degrade the performance of safety functions to an unacceptable level" are new and subjective. In fact, the language is not new. It was taken from the statement of considerations (SOC) for the original issuance of $50.65 on July 10,1991 (56 FR 31306-31323). The staff acknowledges it could be argued that because the original paragraph (a)(3) was silent on the use of the assessment, an explicit requirement to use the assessment constitutes a new requirement. However, the staff believes requiring that the assessment results be used codifies

- the Commission's originalintent as reflected in the original rule's SOC. In any case, because paragraph (a)(4) of the proposed rule could be interpreted as meaning that a risk significant configuration would not be permitted under any circumstances, regardless of degree of risk and

- duration' of that risk, the term

• manage" has been introduced to maintain the Commission's original intent and also to be consistent with the flexibility that $50.65 gives licensees.

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[ The staffs expectations for licensee assessment activities have not changed.

j expected to review the current plant configuration and the changes anticip ,

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the proposed maintenance activities. Licensees are

~ ~ deterministic judgments to in-depth analyses l1s expected to be commensurate i* complexity of the involved configurations. (More detail on staff expectations i discussion under item 4 of Section lit, *The Final Rule," in thefederal Reaister notice,

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Attachment 1.)

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The second NEl concern addressed the apparent overlapping regulatory requiremen

} technical specifications (TS) and the revised maintenance rule. Under certain conditio

} plant's TS may allow a structure, system, or component (SSC) to be out of servi

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i maintenance assessment proposing the removal of that same SSC from service ma that configuration. Also, it is possible that allowed outage times of TS may not be in agreement with out-of-service times resulting from the f

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[ single failures of plant SSCs but have been used by lice

[ to proposed maintenance activities that will directly, or may inadvertently, result in e being taken out of service, in general, TS may serve as the pre-analyzed assess licensee proposes that a single SSC be remov 'd from service for maintenance. However, the licensee proposes that aCitional SSCs undergo concurrent maintenance, the conf '

~ becomes more complex, and More sophisticated assessment processes are necessary a appropriate. The staff believes that TS allowed outage times were not developed fo '

inappropriate for controlling concurrent removals of SSCs from service during plan The staff expects that, while performing on-line or shutdown maintenance, the licensee remain in conformance with its TS. In addition, the licensee's pre-maintenance planning is expected to include, to the depth necessary for the complexity of the maintenan identification of the equipment to be protected during the maintenance activity and (2) contingency plans that identify equipment to be restored first, if necessary, should a r

equipment failure occur, and compensatory actions to be taken should the proposed o duration be exceeded. The revised wording requiring licensees to assess and manag

is intended to cause the licensee to determine its options and follow a prudent course of consistent with the staffs expectations outlined above. , . -.

The third NEl concem was that the scope of SSCs subject to the proposed assessment

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requirement was impractical. Paragraph 50.65(b) defines the scope of SSCs that

by the rule (with the exception of SSCs for decommissioning plants). Chapter 11.0 of NUMARC 93-01,

• Industry Guideline for Monitoring the Effectiveness of Maintenance at N Power Plants," Revision 2, dated April 1996 (which has been endorsed by Regulatory j

Guide 1.160, " Monitoring the Effectiveness of Maintenance at Nuclear Power Plants,"

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' Revision 2, dated March 1997), is entitled ' Evaluation of Systems to bc Removed from Chapter 11.0 guidance makes the assessment a three-step process: (1) Identify functions to be maintained, (2) identify SSCs that support key plant safety functions, and ( ,

consider the overall effect of removing SSCs from service on key plant safety functions. l

! Requiring,instead of recommending, those assessments does not change the expec l 9

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the assessments need only involve SSCs associated with initiating or mitigating impacts on plant 1 safety. This expectation will be emphasized in Revision 3 to Regulatory Guide 1.160.

I The staff recognizes that the coordination between the effective date of the revised rule and the issuance of the revised regulatory guidance is an important consideration. In SRM 97-173,

., - dated December 17,1997, the Commission indicated that development of the regulatory

't guidance should not delay issuance of the final maintenance rule. Later, in SRM-98-165, dated l September 3,1998, the Commission requested the staff to strive to present the regulatory

- guidance no later than the final rule package. The staff has prepared draft guidance, which will be provided to the public for comment. The staff agrees with the several public comments that the rule should not be made effective until a reasonable period subsequent to the issuance of the final regulatory guidance. In SECY-98165, dated July 2,1998, the staff committed to providing guidance 120 days after the rule is issued. The staff now requests that the effective

{ date of the revised rule be 120 days after issuance of Regulatory Guide 1.160, Revision 3.

CONCLUSION:

The staff believes that the revised wording, when supported by appropriate guidance that will be issued 1,20 days before the effective date of the rule, will accomplish the Commission's intent for the modification.

This paper provides the Commission with the rulemaking package for the final rule that amends 10 CFR 50.65 as directed. The regulatory analysis supporting this final rule is included as Attachment 2.

COORDINATION The Office of the General Counsel has reviewed this final rule and has no legal objection to its content.- The Office of the Chief Financial Officer has reviewed this final rule for resource implications and has no objection to its content. The Office of the Chief Information Officer has, reviewed this final rula,for information technology impacts and has no objections. The Advisory

. Committee en Reactor Safeguards has reviewed this final rule and has no objections. The

- Committee To Review Generic Requirements has reviewed this final rule and has no objections.

No changes to the Enforcement Policy are required as a result of this rulemaking. Revisions to the Enforcement Manual will be considered to address this rulemaking and the lessons learned since initialimplementation of the maintenance rule.

RESOURCES:

Resources for possible follow-up inspection activities are budgeted at a total of 1.0 full-time-equivalent position and $400,000 in contract support. . ---

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-RECOMMENDATIONS: .

That the Commission: -

1. -~~Acorove the notice of final rulemaking~(Attachment 1) for publication '

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Recister.

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2.

Certify that this rule, if issued, would not have a significant economic impact on a l

! substantial number of small entities to satisfy the requirements of the Regulatory /

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Flexibility Act,5 U.S.C. 605(b).

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3. _ Identify that a notice will be published in the Federal Re I becomes effective in 120 days.

- 4. N._gte that:

a. This final rule will be published in the Federal Reaister; i

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b. The appropriate congressional committees will be informed (Attachment 3) 1

c. A public announcement (Attachment 4) v,ill be issued when this final

• with the Office of the Federal Register; e

d.

This final rule contains no new or amended information collection requiremen I e.

Forms to be submitted for federal rules under the Congressional Review Act a Attachment 5; and i

f. Copies of the Federal Reaister notice of final rulemaking will be dist k affected Commission licensees. The notice will be sent to other interested

! upon request. . , , , _ ,.

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f William D. Travers - . . . .. .. .

Executive Director

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Attachments: 1. Federal Reaister Notice

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2. Regulatory Analysis

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4. Public Announcement

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i NUCLEAR REGULATORY COMMISSION

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10 CFR Part 50 "p --

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Monitoring the Effectiveness of Maintenan:e at Nuclear Power Plants I,

• AGENCY: Nuclear Regulatory Commission.

ACTlON: Final rule.

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SUMMARY

The Nuclear Regulatory Commission (NRC)is amending its power rea regulations to require that licensees assess the effect of equipment mai?ena

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capability to perform safety functions before beginning any maintenance activity o systems, or components (SSCs) within the scope of the maintenance rule. Th clarify that these requirements apply under all conditions of operation, includin that the assessments are to be used so that the increase in risk that may result from the 1

maintenance activity will be managed to ensure that the plant is not inadvertently pla condition of significant risk or a condition that would degrade the performance of sa

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to an unacceptable level.

5 EFFECTIVE DATE: The final rule becomes effective 120 days after issuar:ce of Revi 1 Regulatory Guide 1.160," Monitoring the Effectiveness of Nuclear Power Plan - - -

publish a document in the Federal Register that announces the issuance of a

regulatory guide and specifies that the final rule becomes effective in 120 days.

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• 2 7 FOR FURTHER INFORMATION CONTACT: Richard P. Correia, Office of Nuclear ReaEtor 9

Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, 301-415-1009,

- e-mail rpe@nre. gov.

f SUPPLEMENTARY INFORMATION:

1. Background

The NRC's maintenance team inspections of all nuclear power plant licensees in the late 1980s found the lack of consideration of plant risk in prioritizing, planning, and scheduling

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i maintenance activities to be a common weakness. To address that weakness, paragraph (a)(3) of 10 CFR 50.65, the maintenanc: rule, currently includes the provision that *(l)n performing monitoring and preventive maintenance activities, an assessment of the total plant equipment that is out of service should be taken into account to determine the overall effect on performance of safety functions." The maintenance rule was issued on Juiy 10,1991 (56 FR 31306).  ;

During plant visits in mid-1994, several NRC senior managers expressed concems that licensees were increasing both the amount and frequency of maintenance performed during {

power operation without adequately evaluating safety when planning and scheduling these maintenance activities. The NRC Executive Director for Operations (EDO) addressed these concems regarding the safety implications of performing maintenance while at power to the President of the Institute of Nuclear Power Operations (INPO) in a letter dated October 6,1994.

I in this letter, the EDO noted that it appeared that some licensees were either not following INPO guidelines for the conduct of maintenance and management of outages or had adopted only _

portions of the guidance. The EDO also recommended that INPO support the Nuclear Energy

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. institute (NEI) and appropriate utility managers during meetings with NRC senior managers to discuss the concerns they raised during the site vis,ts.

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3 The growing amount of on-line maintenance (i.e., maintenance d

h being performed by licensees and inadequate pre-maintenance ass I -- .__.

Commission's concem.

To address this concem,to clanfy the plant operating conditions under whi

, l maintenance rule is applicable, and to make the requirements fully enfo

• published proposed revisions to 10 CFR 50.65 in the Federal Regis (63 FR 52201-52206). The 75-day comment period closed December 14,19 11.

Comments on the Proposed Rule Twenty-nine comments were submitted during the comment period, and five submitted after the comment period closed. Copies of the letters are availabl inspection and copying for a fee at the Commission's Public Docum Street, NW (Lower Level), Washington, D.C. The last public comment was rece December 29,1998.

All comments were considered in formulating the final rule. The 34 comments were submitted by 26 utilities with operating power reactors, one ut l

decommissioning status facility, three nuclear industry service companies or c) individual, one State agency, NEl, an industry group, and one law firm repr utilities. Twenty-nine commentors endorsed the NEl comments. NEl stated letter that the industry generally supports the Commission's intent in the p number of significant concems that should be addressed before rulemakin

, l commentors who did not endorse the NEl comments, one (combined S l the concept of the proposed rule and provided comments to enhance it, an individual and a utility) provided recommendations in specific areas to enh rule. Two of the commentors (a consultant and a consulting firm) stated that th unnecessary and presented supporting reasons.

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r 4 c, The comments have been grouped under the following general topics:

1. Ruleissuanoe --,_

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. 2. New, vague, ambiguous, undefined 1erminology in the proposed rule i:

,- 3. Scope issues j

4. Suggestions for wording modifications

5. Regulatory controls overlapping technical specifications

, 6.' Performing assessments

. 7. Assessing and managing risk

8. Emergent maintenance requirements

9. Documentation of the assessment

10. Definition of availability

. 11. Backfit and regulatory analyses

12. Regulatory analysis cost estimates

13. Application to decommissioning plants.

Summaries of the grouped comments and discussions of the NRC responses follow.

1. Rule issuance.

Comment.' One commentor, a utility, stated that they consider the proposed rule unnecessary, and NEl and other utilities stated that the proposed rule, as written, should be

withdrawn. However, they also stated that if the rule is approved, Regulatory Guide 1.160

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i should be revised and issued before finalizing the changes to the rule.

. Response. The NRC has determined that the rule is necessary and believes that the

, performance of this type of assessment is prudent because of changes in industry maintenance practices and findings during NRC inspections of maintenance rule programs. When the -

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maintenance rule was first promulgated in 1991, the NRC had not foreseen the significant i . _ _ .. -_ _ .

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5 changes licensees would be making in maintenance practices. To en d t efficiency, made increasingly necessary by the rate deregulation of the ~~

l licensees are shortening their refueling outages by performing mo is at power. At power maintenance practices have evolved to the p ff systems and components taken off line, but also multiple systems an h

I line simultaneously. Taking systems and components off line for mainten f

i increase in risk because of the greater probability of an accident or a t f

that occurs from expected random equipment failures. In addition, althoug

! rule baseline inspections of all operating nuclear power plant sites found l.

1. implemented programs to perform the assessments, about half of t <

discemable weaknesses in this area, including instances in which, in accor licensees

• own programs, assessments should have been made but were not.

The NRC agrees that it is appropriate to revise Regulatory Guide 1.160 t -

" clarifying guidance before the final rule's effective date. Accordingly, R Guide 1.160 will be prepared for public comment and will be published in f P

before the effective date of the rule.

2. New. vaaue. ambicuous. undefined terminoloov in the crocosed ~lru Comment. Most commentors identified concems related to the proposed rull

. introduction of new, vague, ambiguous, or undefined terminology and reco ,

e rule be withdrawn and reissued for public comment after substantial mod utilities indicated that terms such as

• risk-significant condition" and ' u

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be explicitly defined.

_ Resoonse. Paragraph (a)(4) has been reworded. Guidance for the revis

appears below in item 4 of Section 111,"The Final Rule."

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3. Scope issues. l j Comment. Many commentors stated that assessments required by the proposed rule j i should apply only to high safety-significant SSCs. NEl and utilities expressed concems that the

,- scope of SSCs subject to assessments was impractical. Such broad scope would dilute j attention from high safety-significant SSCs by requiring too many detailed assessments. )

Response. Paragraph 50.65(b) defines the scope of SSCs that are covered by the rule (with the exception of SSCs for decommissioning plants). Chapter 11.0 of NUMARC 93-01, l

" Industry Guidelines for Monitoring the Effectiveness of Maintenance," Revision 2, dated April

1996 (which has been endorsed by Regulatory Guide 1.160, Revision 2, dated March 1997), is i

entitled " Evaluation of Systems to be Removed from Service." Chapter 11.0 guidance makes the assessment a three-step process: (1) Identify key p! ant safety functions to be maintained, (2) identify SSCs that support key plant safety functions, and (3) consider the overall effect of removing SSCs from service on key plant safety functions. Requiring, instead of recommending, those assessments does not change the expectation that the assessments need only involve SSCs associated with initiating and mitigating impacts on plant safety -

functions.

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4. Succestions for wordino modifications.

Comment. Five commentors provided suggestions clarifying regulatory text. Two of

. these commentors stated that the plant configuration should be defined as 'SSCs within the

, scope of the rule," and three commentors suggested limiting the scope of maintenance activities

. to those that result in removing equipment from service.

Resoonse. The NRC disagrees with these suggested languaje changes. The rule currently applies only to SSCs within the scope of the rule. A revision to specify this is not  ;

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needed. Certain maintenance activities are performed that do not remove equipment from

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such a valve was to inadvertently' stick shut, a' transient could ensue'~Those scenarios

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assessed and managed to ensure that the risks associated with these activities are properf identified and controlled.

5. _Reculatory controls overlaooina technical soecifications.

Comment. Several commentors stated that there is a need to reconcile the overlapping regulatory regimes of the maintenance rule, technical specifications (TS), and the co _,

risk management program (CRMP) (described in Regulatory Guide 1.177, "An Approach Plant-Specific, Risk-informed Decisionmaking: Technical Specifications"). NEl and the uti were mainly concemed with the overlap of regulatory controls in the revised rule and TS.

Response. The NRC agrees that some apparent overlap exists among these regulatory l controls. Under certain conditions, a plant's TS may allow an SSC to be out of service, .! while i y

. pre-maintenance assessment proposing the removal of that same SSC from serv ce ma indicate a need to take other actions to preclude that configuration. It is possible that allow outage times of TS may not be in complete agreement with reasonable out-of-service tim .

resulting from the required assessments. However, TS limiting conditions for operatio part, developed to address random single failures of plant SSCs; they were not inten used by licensees as rationale for removing multiple SSCs from service to perform on-line i

maintenance. In general, however, TS may serve as the pre-analyzed assessment when a licensee proposes to remove a single SSC from service for maintenance. Paragraph (a -

intended to cause the licensee to determine its options and follow a prudent course of action.

. . However, while performing on-line or shutdown maintenance, the licensee will remain in

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E' conformance with its TS.'

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j in NRC staff requirements memorandum dated June 29,1998, for SECY-98-067, the L

i Commission directed the NRC staff to take actions to ensure that CRMP regulatory guidance  !

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j I conforms to the provisions of the final maintenance rule. After revisions to the maintenance rule )

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are completed, the NRC will expeditiously support licensee requests to remove the CRMP

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requirements from plant TS.

6. Performino assessments.

[ Comment. NEl and the utilities expressed the need for clarification of when an j I -

assessment would be required, the level of complexity necessary in the assessment, and the criteria to be used to evaluate the adequacy of the assessment process.

Response. Please refer to the discussion in item 4 of Section !!!, "The Final Rule,"

below.

7. Assessino and manacino risk.

Qomment. Three commentors expressed similar views related to high-risk activities.

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One noted that, under suitable controls, a shorter time in a more risk-significant configuration may be safer than a longer time in a less risk-significant configuration. Another noted that high risk-significant activities should be recognized and avoided, where practical, and limited in

.: duration when they are necessary. The third noted that the proposed rule does not address  ;

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situations in which failure to perform a maintenance activity may have a greater impact on risk

than performing the high safety-significant activity. ,-

T 2 Resoonse. The NRC agrees that the proposed rule precluded entering risk-significant t-configurations, no matter the duration, when, in fact, situations may exist that would yield a net safety benefit by performing maintenance in a risk-significant configuration for a short time. The i . rule has been revised to require licensees to understand their options with respect to risk and to e __. : -

manage their maintenance activities according to their best judgment.

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• 8. Emeroent maintenance reauirements.

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.. _ Comment. .Two commentors sisted that the proposed rule does not a

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- expectations for revising assessments upon the discovery ofii previouslyiunkno

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9 requiring maintenance (emergent maintenance). They also expressed conce 3-i I

emergent maintenance activities are not completed immediately, the plant could bI l.

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r i Resoonse. Under the revised rule, an assessment should be initiated following the discovery of emergent failures or changes in plant conditions to determine the ..

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the failure or the change in plant conditions. For s'dditional information on this subject, see the discussion in item 4 of Section 111, "The Final Rule," below, i

. 9. Documentation of the assessment.

I Comment. Three utility commentors stated that the proposed rule is not explicit eno regarding assessment documentation expectations. -

Resoonse. The rule has no explicit documentation requirements. Ins!pd,the rule emphasizes performance. A licensee's assessment process is expected to iden on safety that is caused by the performance of maintenance.1.icensees should use documentation to the extent necessary to assure themselves that the requirement for an assessment has been acknowledged and performed adequately. NRC expectations licensee will have a requirement for the assessments and an explanation of the proc i'

- followed in its maintenance rule program, along with a description of assessment t s-t used and their limitations, implementing procedures, and explicit direction - .- -

covering inst

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when the plant configuration is or is propose [to be outside the span of the asse Further. the assessment process is expected to be incorporated into the mainten

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and scheduling process and into work package requirements. Moreover, control room w .

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10 expected to documerit out of service equipment, and control room operators are expected to i

f - understand, use and know the limitations of the assessment tools.

. 10. Definition of availability.

e 3 Comment. Three commentors stated that the definition of availability will be key to this rulemaking. They also stated that the availability definition should take into account the time

$ required to restore the functionality of an SSC and should also be risk informed.

Resoonse. A definition of availability for licensee maintenance rule programs is set forth 1 in NUMARC 93-01, Revision 2, which was endorsed by the NRC in Regulatory Guide 1.160,

Revision 2 (March 1997). Additionally, in the instance where an SSC is taken out of service for testing but could be manually activated, the NRC has accepted that, as long as tha controlling operator's procedure would specify an action that would produce an automatic initiation of the out-of service SSC in the event of an accident or transient during the test, the SSC could be considered availabla. (Meeting Summary - November 19,1991 NRC/NUMARC Public Meeting on the Development of Guidance Documents for the implementation of the Maintenance Rule (10 CFR 50.65), R.P. Correia, Office of Nuclear Reactor Regulation, memorandum to E.W.

Brach, Office of Nuclear Reactor regulation, dated Novembe. _3,1991.)

11. Backfit and reou!atory analyses.

1 Comment. One commentor stated that the regulatory analysis does not justify the expansion of the maintenance rule to " normal shutdown operations" and that a revision of the analysis to better consider such expansion would show through backfit considerations that the i

l expansion is not justified. Another commentor also presented a concem that the overall implications of the rule were not supported by the backfit analysis.

7 Resoonse. The new preamble to the rule is an introductory sentence clarifying that the L .

rule applies under all operating conditions, including normal shutdown. The Commission e.. s- . . , , ..-, ...m nn - - - ~ . . , _ . ~ . ~ , . . ... . . - . - - - - - - - - - - - - - - . - - ~ ' ~ ~ ' " #

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11 d by the NRC intended the rule to apply to all operating conditions, and it has been im -

. The overallimplications of the rule were assessed in

._ staff consistent with suc h an interpretation ~-~~-

1991.

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the b'ackfit siialysis' f6r theliiriginaliitaintenance rule, which was issued J

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12. Reculatory analysis cost estimates.

Comment. One commentor raised the concem that if facilities are i l ting numerical models for every combination of low safety-significant SSCs

" the program would be significantly higher than estimated in the regula Resoonse. The NRC does not expect licensees to develop numen .

h l it f combinations of low-risk-significant SSCs. The regulatory analysis sta

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[- assessments to be performed can vary, depending upon the SSCs to b i f maintenance, it was presumed that assessments involving SSCs h

• ll i could be performed in an uncomplicated, deterministic manner and that I

program would be dominated by the need for assessment of co

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when taken out of service simultaneously, could have an adverse effe the facility. Additionally, the licensee controls the degree of complexity

' configuration and, therefore, controls the level of sophistication req _.

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13. Anotication to decommissionino olants.

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Comment. One commentor presented concems regarding the applic T .

plants in a decommissioning status. The commentor requested the NRC remove the applicability of the rule to decommissioning status  !

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modest level of fission product decay. .

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Resoonse. This rulemaking is focused on requiring pre-maintenanc -.

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plant risk. However, the NRC is considering the issue in a separate t -- .

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~ 111. The Final Rule The final rule amends 10 CFR 5').65 as follows:

1. An introductory paragraph has been added to 10 CFR 50.65 clarifying that the rule applies under all conditions of operation, including normal shutdown. This introductory language reads as follows: "The requirements of this section are applicable during all conditions of plant t

< operation, including normal shutdown operations." The intent of this paragraph is to ensure that 6 assessments are performed before maintenance activities when the plants are shut down as i well as when the plants are at power. (Note that the word "section," as used in this rulemaking, means all of $50.65.)

2. The second sentence in paragraph (a)(3) has been revised as follows: "The evaluations shall take into account, where practical, industry-wide operating experience." The change was made only to simplify the language and is purely editorial.

. 3. The last sentence of partgraph (a)(3), containing the current, non-mandatory 1 provision for performing safety assessments, is deleted. The revised paragraph (a)(3) now i I

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contains only the requirement for periodic, programmatic, long-term review.

4. A new paragraph, (a)(4), has been added requiring the performance of assessments.

i-l The new paragraph states: "Before performing maintenance activities (including but not limited

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I to surveillances, post-maintenance testing, and corrective and preventive maintenance) on structures, systems, or components within the scope of this section, the licensee shall assess l f

and manage the increase in risk that may result from the proposed maintenance activities." _

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Separating the assessment requirement from the long-term review requirement in paragraph 1 (a)(3) will more clearly distinguish between the two types of activity. .. .

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The intent of this requirement is to have licensees appropriately assess 9

. _ _ to prooosed maintenance activitie's that will directly, or may inadver

-l being taken out of service and then, using insights from the assessmen I

out-of-service time resulting from the proposed maintenance activities while l

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' configuration of the total plant to maintain and support the key safety functions. f

~ Risk is the consequente of an undesirable event that leads to a danger or a h condition. The term " risk" is used to address what can go wrong, its likelihood, a

~ consequences. The risk perspective can be assessed deterministically or pr In general, a risk assessment is necessary before all planned maintena l

! Assessments should also be performed when an unexpected SSC failure initi

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maintenance activities or when changes to plant conditions affect a previously p  :

assessment. However, the reevaluation of a previous assessment should not

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' delay, the plant staffs taking timely actions to restore the appropriate SSC compensatory actions necessary to ensure that plant safety is maintained.

restored to service before performing the assessment, the assessment nee Assessments may vary from simple and straightforward to highty complex I

- degree of sophistication required for the assessment notwithstanding, t assessment process will examine the plant condition existing before the com maintenance activity, examine the changes expected by the proposed ma

' identify the increase in risk that may result from the maintenance activity. T

' expected to provide insights for identifying and limiting risk significan _ . . _ _ . . _ . . . . _ _ _ _

their durations. __ __

I The level of complexity necessary ir5 the assessment would be expected to plant to plant, as well as from configuration to configuration, within a g .-_

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4 14 f'. licensee proposes to remove a single SSC from service for maintenance while no other SSC is .

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- out of service, a simple deterministic assessment may suffice. If the SSC is covered by TS, then i.

the assessment could be as simple as confirming the relevant requirements of TS. When one f SSC is out of service and the licensee proposes to remove a second SSC from service for j j

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! . maintenance, the assessment could be simplified through the use of a table of results for pre-

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analyzed combinations, typically high-safety-significant SSCs paired against each other.

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I However, more detailed assessments are required if a licensee proposes to remove multiple l SSCs from service during power operations or to remove from service systems necessary to

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• maintain safe shutdown during shutdown or startup operations. These more detailed -

t assessments are expected to involve probabilistic analyses where possible, and to also include considerations of key safety functions to be maintained and defense in depth.

4 The NRC believes that an appropriate assessment and management process should include the following considerations:

a. The likelihood that the maintenance activity willincrease the frequency of an initiatinD L

event;

b. The probability that the activity will affect the ability to mitigate the initiating event;

c. The probability that the activity will affect the ability to maintain containment integrity;

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d. Whether multiple trains are affected; -

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. e. How probabilistic insights are used;

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consideration);

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1. Scope and quality of analysis for quantified assessments.

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!- . In general, the NRC expectation regarding managing the risk is a scruta e proce i

controlling or limiting the risk increase of the proposed maintenance activities. This pr shoulo include an understanding of the nature (i.e., affecting the core damage, or l relea 's frequency) and signifbance of the risk implications of a maintenance configura '

the overall plant baseline risk level. For example, risk-significant plant configuratio

$ generally'be avoided, as should conditions where a key safety function would i ll i ifi ant

. degraded while conducting maintenance activities. The effective control of potent a

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risk increase due to an unexpected failure of another risk important SSC can be reas i'* assured by planning for contingencies, or coordinating, scheduling, monitoring, a the duration of planned maintenance activities. , , ,

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t Environmental Assessment Finding of No Significant Environmental impact:

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i The Commission has determined under the National Environmental Policy l

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. l r ' as amended, and the Commission's regulations in Subpart A of 10 CFR Part , \ 51 th

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rule is not a major Federal action significantly affecting the quality of the human ) env i

E and, therefore; an environmentalimpact statement is not required. The environme F assessment that forms the basis for this determination reads as follows: .

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16 Identification of the Prooosed Action The Commission is amending its regulations to require commercial nuclear power plant licensees to perform assessments of changes to the plant's status that would result from maintenance activities before performing the maintenance activities on structures, systems, and components (SSCs) within the scope of 10 CFR 50.65, the maintenance rule. Thus, the maintenance rule has been modified by adding an introductory sentence to clarify that the rule applies under all conditions of operation, including normal shutdown; by making editorial revision to the second sentence of paragraph (a)(3); by deleting the last sentence of paragraph (a)(3); and by creating a new paragraph, (a)(4),

that requires licensees to assess and manage the risk that may result from proposed maintenance activities.

The Need for the Proposed Action Formerly, paragraph (a)(3) of the maintenance rule was in the form of a recommendation because it read as follows: "(l)n performing monitoring and preventive maintenance activities, an assessment of the total plant equipment that is out of service should be taken into account to determine the overall effect on performance of safety functions.' The Commission believes that the performance of this type of assessment is prudent. The maintenance rule baseline inspections, performed at each operating nuclear power plant site, found that all licensees have implemented programs to perform the assessments. However, about half of the sites had programs with discernable weaknesses in this area, including instances in which, in accordance with the licensee's own programs, assessments should have been made but were not. Because of the hortatory nature of the assessment provision in $50.65(a)(3), the Commission cannot

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17 s are free to remove ensure thatlicensees perform the assessments. Moreover, license desire. This final

-the performance of the assessments from their tprograms as they

" rule perm ts i the Commission to ensure that licensees perform the asse appropriate. 3 d l

Removing the provision regarding safety assessments f .

1-requirement I creating for it a new, separate paragraph, (a)(4), disassociates rogram's the

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from the more time-dependent requirementd availability for evaluating for .

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effectiveness at maintaining an appropriate balance between relia

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each SSC. In the new paragraph, the requirement for assessmen -

p f Because there were stipulated to ensure that licensees will perform those assessment hich plant conditions

! d questions regarding when the assessments were to be performe aragraph

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are to be evaluated, and how the assessments were to be used,

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- (a)(4) describes that the assessments are to be dperformed ected be or  !

maintenance activities, are to examine pre-maintenance pla I .,

d to manage changes as a result of the proposed maintenance activity, an

• i the increase in risk that may result from the maintenance activity.

EnvironmentalImoacts of the Prooosed Action f- ,

This final rule requires that commercial nuclear power posed v certain assessments of the status of plant equipment before pe  :

! f ti ness of 1-I maintenance activities. The purpose of this change is to incr . . .

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18 (1) Perform an assessment of the plant conditions before the proposed maintenance and the changes expected to result from the proposed maintenance activity; (2) Ensure that the assessments are performed when the plant is shut down as well as at power; and (3) Manage the increase in risk that may result from the proposed maintenance activity.

The Commission believes that proper implementation of the rule will reduce the likelihood of an accidental release of radioactive material caused by imprudently prioritized, planned, or scheduled maintenance.

The determination of this environmental assessment is that there will be no significant ,

offsite impact to the public from this action. The NRC has also committed to complying with Executive Order (EO) 12898, " Federal Actions to Address Environmental Justice in Minority i

Populations and Low income Populations," dated February 11,1994, in all its actions. The NRC has determined that there are no disproportionate, high, or adverse impacts on minority or- i low-income populations, in the letter and spirit of EO 12898, the NRC requested public l l

comment on any environmentaljustice considerations or questions that the public thinks may be l

related to this rule but somehow were not addressed. No public comments on this issue were l received. I States Consulted and Sources Used The NRC sent a copy of the proposed rule to every State Liaison Officer and e.,e requested his or her comments on the environmental assessment. No comments were

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received on this issue.

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.J 19 Paperwork Reduction Act Statement This final rule does not contain a new or an amended information

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- _ subject to the requirements of the Paperwork Reduction Actof 199

Existing requirements were approved by the Office of Managem i

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! number 3150-0011.

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^ Public Protection Notification t .

! if a means used to impose an information collection does not displa .

i OMB control number, the NRC may not conduct or sponsor, and a aper .

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! respond to, the information collection.

i Regulatory Analysis i The Commission has prepared a final regulatory analysis for this rule l

examined the costs and benefits of the attematives considered by th 10 CFR 50.65, the maintenance rule. Those attematives were to (1) m l

rule, (2) require the safety assessments currently recommended in pa -

d and (3) make comprehensive revisions to paragraph (a)(3) of the ru I the selection of Attemative 2 as the preferred course of action. Details o

selection are contained in the regulatory analysis, which is available Public Document Room,2120 L Street NW (Lower Level), Washin the analysis may be obtained from Richard P. Correia, Office of Nu

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U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, 3 ~

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j in accordance with the Regulatory Flexibility Act of 1980 (5 U.S.C. 605(b)), the

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Commission certifies that this final rule will not have a significant economic impact on a substantial number of small entities. This rule affects only the operation of nuclear power plants.

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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 size stanoards adopted by the NRC (10 l.

CFR 2.81'0).

) Backfit Analysis As required by 10 CFR 50.109, the Commission has completed a backfit analysis for this

' final rule. The Commission has determined, on the basis of this analysis, that backfitting to comply with the requirements of this rule provides a substantial increase in protection to the public health and safety or the common defense and security at a cost that is justified by the increased protection.

When the maintenance rule was issued, the NRC had not foreseen the rate deregulation of the electric utility industry and the changes to maintenance practices that licensees would make to enhance operational efficiency. Specifically of concern is the significant increase in maintenance while the plant is at power, permitting shortened refueling outages. At-power maintenance practices have evolved to the point that multiple systems and components are off line simultaneously. Compared to the risk that occurs from expected random equipment failures, the risk of an accident or transient caused by taking systems and components offline for maintenance or from performing maintenance on systems or components while they remain on line could be increased.

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- 21 The objective of this rule is to require that --

(1) Licensees assess the impact of equipment maintenance on the ca -

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to perform safety functions;' arid . . . . . -

(2) Licensees use the results of the assessment before undertaking mainte l

I-activities at operating nuclear power plants to manage the increase in risk caused I-i activities.

(. Thus, the rule adds a new paragraph, (a)(4), that requires the performance of

' {$ assessments, specifies that the scope of the requirement for performing those a f

covers proposed maintenance activities, and specifies that the increase in risk th

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from the maintenance activity must be managed to ensure that the plant is not in

placed in a condition of significant risk or s ,ondition that would degrade t safety functions to an unacceptable level.

This final rule also adds an introductory sentence to 10 CFR 50.65 clarifying

• i applies under all conditions of operation, including normal shutdown; revise sentence of paragraph (a)(3) to simplify the language; and deletes the last sentenc ,

paragraph (a)(3) of the rule. 1 i The details of this backfit analysis have been incorporated in the regulatory '

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the reasons elaborated in the regulatory analysis, which also contains cost inform

-l-I Commission concludes that this modification to the maintenan I

L increase in the overall protection to the public health and safety, and that the ne 1- , _ ,_ ,

rule are justified in view of this incassed level of safety. , _

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Small Business Regulatory Enforcement Fairness Act

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t in accordance with the Small Business Regulatory Enforcement Faimess Act of 1996,

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~Ee NRd Eas determined that this action is not a major rule and has verified this determination -

with the Office of Information and Regulatory Affairs of OMB.

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National Technology Transfer and Advancement Act The National Technology Transfer and Advancement Act of 1995, Pub. L.104-113, l

. i requires that Federal agencies use technical standards developed or adopted by voluntary consensus standards bodies unless the use of such a standard is inconsistent with applicable

' law or is otherwise impractical. There are no industry consensus standards that apply to the area'of maintenance. Thus, the provisions of the Act do not apply to this rulemaking.

List of Subjects in 10 CFR Part 59 Antitrust, Classified information, Criminal penalties, Fire protection, intergovemmental 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. 552 i

and 553, the NRC is adopting the following amendments to 10 CFR Part 50.

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23 PART $0'- DOMESTIC LICENSING OF PRODUCTION A -

-1..Jhe authority citation _for Part 50 continues to und as fo!!ows:-

AUTHORITY: Secs.102,103,104,105,161,182,183,186,189,68 Stat. 936 948,953,954, 955,956, as amended, sec. 234, 83 Stat. 444, as amended 2133,2134,2135,2201,2232,2233,2236,2239,2282); secs. 201, as amend

Stat.1242, as amended, 1244,1246 (42 U.S.C. 5841, 5842,5846).

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I- Section 50.7 also issued under Pub. L.95-601, sec.10,92 Stat. 2951 (42 Section 50.10 also issued under secs.101,185,68 Stat. 955, as amended (

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f 2235), sec.102, Pub. L.91-190,83 Stat. 853 (42 U.S.C. 4332). Sectio

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' 50.103 also issued under sec.108,68 Stat. 939, as amended (42 U.S.C. 2138 -

i. 50.23, 50.35,50.55, and 50.56 also issued under sec.185, 68 Stat. 955 (42 U Sections 50.33a,50.55a and Appendix Q also issued under sec.102, Pub. L i

853 (42 U.S.C. 4332). Sections 50.34 and 50.54 also issued under sec

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i U.S.C. 5844). Sections 50.58,50.91, and 50.92 also issued under Pub. L. 97 2073 (42 U.S.C. 2239). Section 50.78 also issued under sec.122,68 Stat. ^

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also issued under sec.184,68 Stat. 954, as amended (42 U.S.C.

2152). Sections 50.80-50.81 2234). Appendix F also issued under sec.187,68 Stat. 955 (42 U.S.C. 2237).

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2. In $50.65, an introductory paragraph is added, paragraph (a)(3) is rev b.'

j paragraph (a)(4) is added, to read as follows:- , ..a ..

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.g 650.65 Reauirements for monitorina the effectiveness of maintenance at nuc g~ "- -

I The requirements of this section are applicable during all conditions of p f-including normal shutdown operations. .m. _ . .

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preventive rnaintenance' activities shall be evaluated at least every refueling Bicle provided thi~~ ~

.: interval between evaluations does not exceed 24 months. The evaluations shall take into  :

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! account, where practical, industry-wide operating experience. Adjustments shall be made where necessary to ensure that the objective of preventing failures of structures, systems, and i i

components through maintenance is appropriately balanced against the objective of minimizing i  ?

unavailability of structures, systems, and components due to monitoring or preventive maintenance.

(4) Before performing maintenance activities (including but not limited to l

surveillances. p.st-maintenance testing, and corrective and preventive maintenance) on structures, systems, or components within the scope of this section, the licensee shall assess and manage the increase in risk that may result from the proposed maintenance activities.

Dated at Rockville, Maryland, this day of ,1999. i For the Nuclear Regulatory Commission.

1 Annette Vietti-Cook, Secretary of the Commission.

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E-Regulatory Analysis

~ Amendments to 10 CFR 50.65

- - - -Monitoring the Effectiveness of Maintenance at Nuclear Power Plants .

Introduction

- This regulatory analysis conforms to the guidance as specified in NUREG\BR-0058," Regulatory Analysis Guidelines of the U. S. Nuclear Regulatory Commission," and contains the information and analyses that meet the requirements of both 10 CFR 50.109, the backfit rule, and provisions of the Charter for the Committee To Review Generic Requirements (CRGR), Revision 6, dated April 1996. This backfit analysis demonstrates that the proposed requirements prcvide a substantialincrease in protection to the public health and safety or the common defense and security at a cost that is justified by the substantial increase. Passages that address the items that must be considered in the backfit analysis have been cross-referenced to the appropriate 10 CFR 50.109 citation.' , ,. .. _. .. .

, 1.0 Statement of the Problem ,

On July 10,1991 (61 FR 31006), the U.S. Nuclear Regulatory Commission (NRC) published 10 -

CFR 50.65, " Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants." The Commission took this action because proper maintenance is essential to plant safety and there is a clear link between effective maintenance and safety as it relates to such factors as the number of transients and challenges to safety systems and the associated need

. for operability, availability, and reliability of safety equipment. Good maintenance is also important in providing assurance that failures of other than safety-related structures, systems, anc. components (SSCs) that could initiate, adversely affect, or mitigate a transient or an cccident are minimized. Minimizing challenges to safety systems is consistent with the Commission's defense-in-depth philosophy. Maintenance is also important in ensuring that design assumptions and margins in the original design basis are maintained and are not degraded. Therefore, nuclear power plant maintenance is clearly important in protecting public health and safety. , _

in the late 1980s, the NRC's maintenance team inspections found that although licensees had adequate maintenance programs in place and had shown an improving trend in implementing those programs, a common weakness in those' programs was a lack of consideration of plant risk in the prioritization, planning, and scheduling of maintenance activities. This weakness was one of the major reasons for the pre-maintenance assessment provision in 10 CFR 50.65(a)(3),

which states: "In performing monitoring and preventive maintenance activities, an assessment of the total plant equipment that is out of service should be taken into account to determine the

- overall effect on performance of safety functions." Because this provision uses the word - - -- -

"should" instead of "shall," the legal effect is that the provision serves as a recommendation

- - rather than as a requirement. --- - -- -- - ---

. During plant visits in mid-1994, several NRC senior managers had concems with the fact that licensees were increasing both the amount and the frequency of maintenance performed during

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' power operations. Some licensees were limitin '

out of service as long as it did not violate the plant's technical specifications. H allowable outage times specified in technical specifications are based

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shutdown is required. Technical specifications were not intended to addre times for multiple equipment being out of service concurrently. Furthe l it is acceptable to voluntarily remove equipment from service to perform on -

U the assumption that such actions are bounded by a worst-case single fail p specific design requirement that is contained in a number of the ge l

in 10 CFR Part 50, Appendix A. The NRC senior managers also had co on-shift personnel, planning and scheduling personnel, and licensee mana understanding of the importance of safety systems or combinations of equ f -

have risk significance if taken out of service. It app -

i-plant's safety and to address potential vulnerabilities, were not fully used '

operations and maintenance decision processes. These concems wer -

dated October 6,1994, from the Director of the Office of Nuclear Reactor Re

' Executive Vice President of the Nuclear Energy Institute. The growing amoun performed during power operations and the underutilization of risk insi .,

and maintenance activities are safety concems.

' In SECY-97-055," Maintenance Rule Status, Results, and Lessons Leamed 1997, the NRC staff described the challenge of inspecting and the NRC staff enforce the pre-maintenance assessment provision of 950.65(a)(3). The sta general, licensees have followed the guidance contained in Regulatory Gu

' ' Monitoring the Effectiveness of Maintenance at Nuclear Power Plants," an

' Industry Guideline for Monitoring the Effectiven there is a nexus between safety and having equipment out of service. When th rule was first promulgated in 1991, the NRC staff did not foresee the significant ch licensees would be making in maintenance practic to rate deregulation of the electric utility industry, licensees are shortening t e

maintenance outages by performing more maintenance while the plant is at pow maintenance practices have evolved to the point that not only are major system components taken off line, but also multiple systems and components _._

.f are concurrently. ., ., ,

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However, in the few cases in which the NRC staff has observed weak impl configurations for which the licensee did not adequately assess the config ~

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~ impact, the NRC staff was unable to take actions paragraph (a)(3)in enforcement actions if the failure to perform an adequ L assessment causes, contributes to the severity of, or complicates recovery from l l However, such a failure to perform an assessment . ._

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1 ..._. For these reasons, the NRC staff is amending 10 CFR 50.65(a)(3) to ensure that licensees _.. _

, effectively assess and manage the impact on plant risk that may result from maintenance on SSCs within the scope of the rule. The objective of the rule is to require that licensees use the r~  ; assessment of the impact of risk resulting from maintenance activities on equipment to ensure that increase in risk that may result from maintenance activities does not inadvertently place the I plant in a risk significant configuration, that is, a configuration for which the contribution to the

, incremental annual risk is not insignificant, or in a configuration that would degrade safety functions to an unacceptable level. [{50.109(c)(1)) Additionally, in Staff Requirements Memorandum 97-173, dated December 17,1997, the Commission approved the staff's recommendation to develop this rulemaking, provided text for revisions to 10 CFR 50.65, stated that " extended or protracted regulatory analysis of Attemative 1 (no rule change)is unnecessary," and directed that the regulatory analysis discussion of Altemative 3 (comprehensive rule change) be limited. ,

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2.0 identification and Preliminary Analysis of Altemative Approaches -

i 2.1 Altemative 1-Make No Change to Phragraph (a)(3) in the Rule The first altemative considered is to maintain the status quo and not revise paragraph (a)(3). As ,

noted in SECY 97-055, licensees have, for the most part, voluntarily incorporated the paragraph ]

(a)(3) pre-maintenance assessment provision in their maintenance rule implementation programs using Regulatory Guide 1,160 and NUMARC 93-01 because of the obvious connection between safety and maintenance on equipment. Additionally, some licensees have indicated a willingness to improve their programs to address weaknesses identified during inspections. Thus, the existing codified text could be considered sufficient. When inspections  !

identify deficiencies in the programs of individual licensees, the staff could continue to encourage those licensees to improve their performance.

The obvious advantage of this alternative is that no additional burden would be placed on licensees or on the NRC staff to conduct such a rulemaking.. . .

. The disadvantages of Attemative 1 are that (1) licensees could remove the paragraph (a)(3)

. assessment provision in their maintenance rule implementation programs at their own 3

discretion; (2) since the performance of an assessment is discretionary and not mandatory,

. licensees cannot take credit for their assessment programs under other risk-informed initiatives (unless they make the assessments a requirement through the other initiative); (3) because the l assessments are not required, some licensees could view any efforts to encourage the assessments as a potential backfit; and (4) the NRC staff cannot enforce this provision of the rule.

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2.2 Attemative 2-Change Paragraph (a)(3) of the Rule to Require Assessments

! Under 950.65(a)(4) of the final rule, before performing maintenance activities on SSC scope of the rule, licensees would be required to conduct an assessment of the curren

[ i that will result from the configuration, as'well'as of expected changes to the plant configurat on proposed maintenance activities, to determine the overall effect on performance of sa g

i functions, Licensees would also be required to use the results of the assessment to manage risk to ensure that the increase in risk tnat may result from maintenance activities does not inadvertently place the plant in a risk-significant configuration or a configuration that would

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degrade safety functions to an unacceptable level. The SSCs that are subject to the ~

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requirements of the rule are those that are safety related, and certain non-safety-relat as defined in $50.65(b) and (a)(1). Licensees have programs in place for implementing i

Regulatory Guide 1.160 and the industry guidance document it endorses, NUMARC 93-0l which accepts the existing paragraph (a)(3) recommendation as part ofits program. To co with this final rule and complete this backfit, licensees would need to incorporate the rule _ ,

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changes into their existing programs. ,

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j The final rule will add an introductory sentence to 10 CFR 50.65 clarifying that the rule apphes

' under all conditions of operation, including normal shutdown; will revise the second sentence paragraph (a)(3) for clarity; will delete the last sentence of paragraph (a)(3) of the rulel create a new paragraph, (a)(4), that requires the performance of assessments; will specify da i the assessments are to be performed for all proposed maintenance activities; and will specify that the increase in risk that may occur from the maintenance activity must be managed.

[650.109(c)(2)] ._ .

i The advantages of Alternative 2 are that (1) licensees would retain maximum flexibility to '

operate within configurations allowed by their current license as envisioned when the ru originally issued; (2) there would be little or no burden on most licensees because licensees l already have voluntary programs in place in accordance with NUMARC 93-01, which thJ endorsed by Regulatory Guide 1.160, and the weaknesses in those programs that led to the failures to perform assessments found during the baseline inspections could be corrected 'l relatively easily; (3) if licensees fail to perform an assessment (as was found by 7 of the maintenance rule baseline inspections at the 68 operating reactor sites), the NRC staff could use enforcement to require corrective actions that ensure licensees perform ' ~ ~ the assessment

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' the future; and (4), when appropriate, licensees may be able to take credit for their paragraph (a)(4) assessment program in other regulatory initiatives. .

The disadvantages of Attemative 2 are that (1) licensees are,in general, exercising their discretion to perform the assessments, and thus, the NRC may be unnecessarily expending  ;

resources on a rule change mandating the performance of an assessment already being '

i performed voluntarily and (2) it would not address the weaknesses identified durin i .

j baseline inspections pertaining to the quality and technical adequacy of licensees' metho performing the assessments. ~~ ~ ~ ~

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- 2.3 Attemative 3-Make Comprehensive Revisions to Paragraph (a)(3) of the Rule The Statements of Consideration (SOC) for the maintenance rule noted that the assessments would be refined on the basis.of technologicalimprovement and experience. Therefore, as the

- third attemative, the staff considered a comprehensive revision of the paragraph (a)(3) assessment provision to incorporate the use of more modem techr' ology and the experience

- with sophisticated techniques used by some utilities. To remain performance based, the rule

would not prescribe a specific approach. Rather, it would provide considerations that assessment methodologies would have to address, while continuing to give licensees the flexibility to develop specific approaches that best suit the needs of each.

The advantages, of Attemative 3 are that it would (1) require licensees to evaluate and control -

? maintenance activities through technically advanced methods, (2) provide specific limits to the

risk associated with maintenance activities, and (3) establish a foundation upon which other risk-informed regulation could build. Thus, Altemative 3 would address the weaknesses pertaining j

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to the quality and technical adequacy of licensees' methods for performing the assessments identified during the baseline inspections and allow the use of the enforcement policy to require  ;

4 cormctive actions for any of the weaknesses.

The disadvantages of Altemative 3 are that (1) such a rule would have a broad impact on other current and future rules and, instead, should be sepsiated from this maintenance rule and developed as a rule that would be used generically for other risk-informed regulation; (2) since it would likely result in the use of probabilistic methods, Alternative 3 would impose a substantial burden on both licensees and the staff; and (3) because of the greater burden on licensees,  ;

Attemative 3 may be less likely to have industry support relative to Attemative 2.

3.0 Estimation and Evaluation of Values and impacts 3.1 Attemative 1-Make No Change to Paragraph (a)(3) of the Rule ,

This attemative is the base case for this regulatory analysis. Therefore, the assumption is made that no licensee performs the pre-maintenance assessments that are recommended in

- $50.65(a)(3). Thus, there would be no impact upon licensees if this attemative is adopted, and there would be no additional resource burden on the NRC. Likewise, there would be no safety benefit to the public.

' 3.2' Altemative 2-Change Paragraph (a)(3) of the Rule To Require Assessments -

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3.2.1 Impact of Altemative 2  ;

I If this altomative is adopted, all licensees would be required to assess and manage the effect  :

that the resulting plant configuration would have on the safe operation of the facility. The degree

. of complexity of the assessments would be expected to differ from plant to plant, as well as from configuration to configuration within a given plant. The characterization of the manpower cost to the licensees is complicated by the fact that the complexity of the assessment will depend upon a number of factors. For example, if a licensee is to take only one or two SSCs off line, the  !

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6 assessment required may involve checking to see that the resulting config violation of technical specifications and possesses the capability of adequ required safety functions. Conversely, if the licensee plans to perform SSCs at the same time, a more complex assessment l ttmayitis be required. T assessments to be performed will also be governed b assessments. One such strategy might be to develop sets of pre-analyzed co Once an analysis has been made of a configuration in which a number of S off line and it is shown that this configuration does not unacceptably increas this same set of SSCs may be taken off line in future maintenance outages if 4 that the resulting and the pre-analyzed configurations are the same.

In Section 2.2 of this regulatory analysis, six modifications to the existing are identified. Because of the nature of these existing requirements and the pro j modifications, the costs and impacts of these amendments are being treated example, item (1), which adds a preamble to the rule, clarifies that the

~ conditions of operation, including normal shutdown. Since the existing langua already applicable to power reactors in all modes, the amendatory langu (2) revises the second sentence in paragraph (a)(3) paragraph (a)(3) does not specify a requirement, it

• (4), (5), and (6) provide definition of the scope and timing of the requirem and benefits are included in the analysis to follow. Us required in item (6), will have an impact on plant operations. There will be ti assessments will reveal that certain maintenance activities should not be perform s

imultaneously and, thus, maintenance schedules will need to be modified ac difficult,if not impossible, to quantify the effects, if any, of these modified ma without information concerning the equipment involved. However, the benefit facility in a risk-managed environment is seen to outweigh the inefficiencies t ,_

introduced through modified maintenance schedules.

To estimate the burden of this alternative to the indus using and maintaining them. This analysis assumes three levels of sophist

~ assessment methodologies. The first wNid be a basic deterministic type by plant operations, maintenance, or engineering, or one that might invo

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, would be detrimental to safety. The second would co that would involve small groups of SSCs or equipment. It is possible that thes i level assessments may also be performed in a deterministic fashion but would '

' analysis of the interrelationships between SSCs and the role they play i that larger numbers of SSCs are to be taken off line I assessment may require quantification of risk using probabilistic risk assessment

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' techniques. Thus, this regulatory analysis considers the costs associated with three levels of-complexity related to the assessment. . ._ _. . .

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The first cost considered is the one-timelcost of developing the methcdologies and the procedures for carrying out the wanous assessments. Estimates received from industry indicate that the cost of developing the basic assessment tools is approximately $20,000, and the cost of developing the higtH:omplexity, PRA type approach is approximately $300,000.8 Forthe purpose of this analysis, it is assumed that the costs for the intermediate assessment development are approximately the same as the basic assessment. Another assumption is that each facility initially developed either a basic or an intermediate methodology. Although many facilities appear to be finding a benefit from moving to the high-complexity methodology, an estimate of the number that will move to the high level i= difficutt to acquire. Therefore, this analysis will develop the upper bound of costs, assuming alllicensees will upgrade. Thus, assuming a total of 68 maintenance assessment programs' will be developed industry-wide at

$320,000 per facility, this activity would incur a one-time cost of $22 million across the industry.

It is anticipated that the aforementioned methodologies will require some modifications over time because of the possibility of changes in plant equipment and the availability of improved technologies and up-to-date PRA data. Industry estimates to both use and maintain the methodologies are $50,000 and $25,000 for the basic and high-complexity assessments, respectively. The higher cost for the basic assessments reflects the need to follow up with PRA-type assessments in the event that a more basic matrix approach is not sufficient. Again, it is assumed that the cost for basic and intermediate assessments is the same. The NRC staff estimates that currently one-third of its licensees use and maintain a high-complexity ^ ~

assessment methodology and two-thirds use a basic or intermediate-level technique. However, to bound the impacts on the conservative side, this analysis assumes that all 68 facilities will utilize either a basic or intermediate-level assessment methodology augmented by a high-complexity methodology. Therefore, the use and maintenance cost for each facility would be

$75,000 per program, or $5.1 million across the industry, annually. If we assume that the average life expectancy of existing nuclear power plants is 20 additional years per facility, the discounted flow of funds at a 7-percent real discount rate is $54 million. As an attemative analysis, using a 3-percent discounted rate, the value would be $75.6 million. -

Another impact considered was differences in facility type, design, and age. Facility type and design will have an impact on the amount of maintenance needed and, thus, the number of pre-maintenance assessments that a facility would be required to perform. The larger or more

'The recurrent costs of updating the methodologies to account for new information and improved technologies will be accounted for separately, ,.

8Unless otherwise noted or assumed, cost estimates are based upon dir'ect staff

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communications with licensee management.

There are approximately 100 operating reactors in the United States. However, many of these units will share maintenance assessment programs because they reside in multiple-reactor sites. The assumption is that only 68 programs will need to be developed.

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However, I s in plant complex facility designs will have more SSCs and, ff thus,i require more i

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s For the most part, however, the aforementioned Thecosts principal are sunk i i t tive in j voluntary compliance with thedioriginal t the shift to and version o nel.

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- nature, dealing with changes to procedures and o I [$50.109(c)(5)]

.r-i 3.2.2 Value of Attemative 2 i Maintenance of plant SSCs is necessary eveni if a mentin pre-maintena _

configuration is not required. Thus, the value of such afi ration requirement is f '

safety that results from performing the assessments if assibly plant is put because equipment is off line for maintenance, demands d f

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ti systems that cannot be met. This circumstance safety system SSCs that are rarely called upon. -

' The final rule does not require any change in the design i or construc plant. Neither does the final rule apply ( )(5)] to activiti construction costs associated with the final rule to be bome by licens When the maintenance rule was first promulgated in 1991, the N significant changes licensees would be making in maintenance li nsees pr operational efficiency in reaction to the rate deregulation while of the ele 3 are' shortening their refueling and maintenance outages t by performin l t

', the plant is at power, At-power maintenance d  :

p are taken off line simultaneously. This maintenance practice could res d to t

likelihood of an accident or transient while the e

~ along with the specifications regarding their scope and their use, are  ;

licensees to manage the risk associated with removing SSCs from se

maintenance by ensuring their plants are not inadvertently l It plac conditions in which the performance of safety functions are degra

i. is this risk avoidance feature of thic altemative that provides i ired a sig

! Attemative 1 and provides the #protection to the n- public health and

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to maintain. [$50.109(c)(6)] i t nance)

Maintenance of plant equipment while the plant is operating atd power (

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9 and maintenance outage durations. During on line maintenance activities, the plant risk associated with an accident that would result in damage to the reactor futl or the release of

- fission products to the environment would increase because of the unavailability of the

_._ equipment taken out of service. . Pilot studies by t eh NRC as well as the industry's maintenance j, rule implementation assessments have shown that the risk impact of maintenance activities can b vary substantially, depending on the duration of the activities and the combinations of equipment

! allowed to be out of service concurrently. Since imprudently planned and managed

maintenance activities have the potential for subjecting a plant to an unacceptable ineren) ental contribution to the annual risk, it is important that the provisions of this final rule be implemented

.to ensure that on-line maintenance is carefully managed to achieve a balance between the I benefits of the maintenance and the potentialimpacts on safety. Hence, the final rule requires that the on-line maintenance process be carefully managed to avoid risk-significant configurations, or configurations that would degrade safety functions to an unacceptable level, and thereby ensure an acceptable margin of safety. Furthermore, the final rule focuses l

attention on methods to evaluate, both prospectively and in real time, the risk impacts of plant configurations so that undesirable risk impacts from maintenance are avoided. Because this is

a performance-based rule, licensees would have flexibility in their selection of evaluation methods and decision criteria as long as they meet the requirement to manage the increase in risk that may arise from maintenance activities. However, the staff would provide guidance in Regulatory Guide 1.160, Revision 3, that would describe methods acceptable to the staff for meeting the requirements of this final rule. [l50.109(c)(3)]

Similarly, because there is a potential risk to the public from an accidental offsite release of "~

radioactive material during shutdown operations, maintenance performed during those operations, too, must be carefully managed. Even though the power levelin the reactor is essentially zero, used fuel and contaminated materials present a potential hazard.

Tne maintenance rule does not prescribe the type, frequency, or duration of maintenance activities but rather requires assessments and management of risk before the performance of maintenance. However, the assessment requirement is expected to greatly reduce the possibility of the plant's being operated in an unsafe configuration. This is likely to result in an

- overall reduction in occupational exposures. [l50.109(c)(4))

in addition to the benefit to public health and safety, other effects such as potential damage to plant SSCs and the possible need for the purchase of replacement energy would be avoided.

. This step would result in a cost savings to the industry that in some measure would offset the increase in costs discussed in Section 3.2.1. While it is impractical to calculate the potential risk benefits of the final rule revision because of the variability, frequency, and repetitiveness of maintenance tasks associated with each plant configuration, the staff's qualitative essessment supports the beneficialimpacts of the final rule change because of nsk-aversion strategies

. resulting from the final change. .

3.2.3 Impact of Attemative 2 on the NRC L , - . _. _ _ _ . . _ . _. _ . _ . . .

The impact of Attemative 2 on the NRC would be twofold. The first impact would be the cost of implementing a rule change. On average, the NRC estimates that a rule change requires 1 person year per year for 2 years. Although Alternctive 2 appears to be a relatively

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I straightforward amendment, it nonetheless would require about 2 NR j-The deterministic analyses required by the basic and intermediate-com i h should require little additional guidance to the licensees. However, ad T form of a regulatory guide is planned to provide licensees with insigh I

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guidance from this body of literature should not require more than l

'The second impact would be the inspection and oversightf of the asse should be straightforward and require minimum extra resources. In ac f h NRC l ~ licensees' implementation of the paragraph (a)(3) assessments is already p j-resident inspector core inspection program. Therefore, similar to the ac f industry, the principal impact on the NRC wou

' in, paragraph (a)(4) and the modest retraining necessary for the appr

~ Nevertheless, the NRC staff is considering the inspection of the impl rulemaking at about 20 licensee sites selected from those licensees tl tha weaknesses during initialinspections of maintenance rule implementati

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. 20 proposed inspections would cost 1 staff-year and $400,000 in contra Thu's, the impacts on the NRC are estimated to be a one-time cost for rule

._ development of 2.25 staff years plus 1 staff-year and $400,000 for im

• These resources have been accounted for in the regional and Headquar i

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3.3 Altemative 3-Make Comprehensive Revisions to Paragraph (a)(3) of the:  !

3.3.1 Impact of Attemative 3 .... .

Altemative 3 is derived as a consequence of the originalintent of the m SOC for 10 CFR 50.65 stated that the expectation was that the assessm i

paragraph (a)(3) would be refined on the basis that the approach would take on a performance-b I

risk, incremental risk per maintenance outage, i j

industry or to the NRC with any degree of certa .,

j highly trained individuals to perform the assessments.

3 f . _ Although the specific impacts of Altemative 3 ha L

limits within which the risk of resultant plant A conf I

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maintenance activities are found to exceed NRC-specified limits.. This trial and error, in tum, may cause delays in maintenance activities and increase the likelihood of component failures.

3.3.2-Value of Attemative 3 c

Although it is impractical to calculate the potential risk benefits of this alternative, several

[E qualitative values have been considered. Altemative 3 would limit maintenance activities through the use of mostly risk-based criteria and would require licensees to evaluate and control maintenance activities through much more rigorous, technically advanced methods. Also,it

> . would establish a regulatory precedent for other risk-based requirements.

3.3.3 Impact of Altemative 3 on the NRC I The resource burden to the NRC of Altemative 3 is expected to be significantly greater than for

. the two lower options of Alternative 2. The NRC would need to develop the risk parameters to be used for setting the, limits that risk may be increased while continuing to operate the facility safely. The specific limits must be developed, evaluated, and approved. Assessment methodologies used to estimate the change in risk parameters must be evaluated and approved by the NRC staff to assure their accuracy and reliability. Implementation of such a rule is expected to require extensive interactions between the staffs of the licensee and the NRC to fully understand and evaluate each methodology. Further, the burden ofinspecting implementation and compliance with the regulation would be likewise complicated. For

- example,in a t;me of shrinking resources, Alternative 3 would necessitate extensive PRA training for region-based inspectors. Because the NRC continues to be a fully fee-recoverable agency, the increased burden would be transferred to the licensee.

Because of the burden that such an approach would place upon licensees,it is unlikely that the industry would support such an approach. Thus, the rulemaking process would be greatly affected, which would result in many industry NRC interactions and many counter proposals by

. the industry requiring staff evaluation and Commission action. The resources required for such a rulemaking should be balanced against the incremental benefits. The NRC inspection program has demonstrated that, by and large, licensees are complying with an Attemative 2

. type of approach even though it is recommended and not required.

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- 4.0 Discussion of Voluntary Compliance With the Assessment Provision of 10 CFR 50.65(a)(3)

NRC's Regulatory Analysis Guidelines direct the NRC staff to not consider the cost of voluntary licensee actions as the cost basis for decisions conceming contemplated regulatory actions, in accordance with the Guideline, the costs of this rule as analyzes above in this regulatory analysis do not consider any expenditures by licensees for voluntary compliance with the non-'

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mandatory provision in paragraph (a)(3) of the current maintenance rule.

However, the guidance also indicates that a sensitivity analysis should be performed to estimate the actualincremental burden that would result from the action. The following discussion represents the sensitivity analysis for the proposed approach (Alternative 2). Alllicensees have some fonn of pre maintenance assessment program as recommended in 10 CFR 50.65(a)(3) 7

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Guide 1.160. The NRC I ating and as addressed in NUMARC 93-01,r mswhich i with is en .

f' . power plant, found that alllicensees have programs n the assessments.. At about half of the power plants, t the inspectors f minor weaknesses or instances of failure to performf ming thethe recommen .  ;

i_ specified in the programs. Since alllicensees have li ees' developed m y assessments to be required under Attemative 2, and ilit at approximatelyld be ,

't methodologies have been found acceptable, the l NRC's t and theassumption

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required to incur the one time 5320,000 cost perh facilitybl for tual t

method annual 575,000 per facility for use and maintenan

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this rulemaking.  ;

5.0 Decision Rationale f 1 i bd Attemative 2 is judged to present ai htforward. substanti is not nearly as great as that of Attemative 3, and the program to l- measure, already in place. Also, fullimplementation of Altemative NRC's 2 sh ts and Altemative 1, clearly the least burdensome fthe o

could remove the paragraph (a)(3) assessment provision in their mai implementation programs at their own discretion. d theAltemative NRC 2 as a 3

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final rule. [$50.109(c)(9)] . . _ _

' 6.0 implementation f The action evaluated in this regulatory analysis h i will be impleme forthis

' a final regulation. A regulation has been selected as the appropriate mec a

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t' NRC TO REQUIRE NUCLEAR POWER PLANTS TO ASSESS A INCREASES IN PLANT RISK BEFORE PERFORMING MAINT!

} The Nuclear Regulatory Commission is revising its Maintenance Rule to require i

nuclear power plant licensees assess and manage the potential increase in r  ;

h from proposed maintenance activities. At present, the rule says that license a

a such an assessment, but does not require it.

NRC took public comments on the proposed rule change last year and incorp them in the final rule to be published in an upcoming edition of the Federal Reoiste_r. .

j NRC has long been concerned about a trend in the nuclear power industry to

' equipment out of service for maintenance while a pla I was first adopted in 1991 show that all nuclear power plant licensees have progra

.aquiring a review of the risk impact on the plant before equipment is taken o r'aintenance. But at seven sites, licensees had not performed such assessments, -

others, assessment weaknesses were found.

The present rulemaking results from a directive given the NRC staff by the Cl after it was informed in 1997 that the Maintenance Rule language on safety assess i T

permissive, rather than mandatory. Also at the Com shutdowns, and that assessments are to be performed for all maintenance activities.

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under the Paperwork Reduction Act of 19957 F. Did you discuss any of the following in the preamble to the rute? 'O e -O e E O.12612. Federalism O 9 O e E O.12630, Government Actions and interference with Constitutionally *O 9 O Protected Property Rights e E.O.12866, Regulatory Planning and Review O O O e E.O.12875, Enhancing the intergovemmental Partnership O 9 O

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r U.S. NUCLEAR REGULATORY COMMISSION April 1999 f[  %,

7, OFFICE OF NUCLEAR REGULATORY RESEARCH Division 1

, i 5  ! Draf t DG-1082

%., ,o# DRAFT REGULATORY GUIDE

Contact:

R. P. Correia (3011415-1009 DRAFT REGULATORY GUIDE DG-1082 ASSESSING AND MANAGING RISK, BEFORE MAINTENANCE ACTIVITIES AT NUCLEAR POWER PLANTS

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A. INTRODUCTION The NRC staff has amended the Maintenance Rule l10 CFR 50.65, by adding a new paragraph (a)(4): ' \

"Before performing maintenance activities (including, but'not limited to, surveillances, post-maintenance testing, and corrective'm'aintenance and' preventive maintenance),

on structures, systems, or components within the scope of this section, the licensee

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shall assess and manage the increase in risk'tlist thEy res' ult from the proposed maintenance activities." o 7 ,

f.

As of July 1998, Maintenance Rule Baseline Inspections at all U.S. nuclear power plant sites were completed. NRC staff experience during the baseline inspections indicated that alllicensees have developed programs to implement the pre maintenance assessment provision of the original paragraph (a)(3). HoweveUthe baseline'insp'ectioris identified a number of instances in which these

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e assessmeff(kre not pef 8ffnd,(includingsofrie that caused a significant increase in risk) and identified wea,knesses in'ficenslees' programs that could result in f ailures to perform adequate assessments gior,to maintenance activities. Partly because of these inspection findings, the Commission app 5Edilthe amehdrrienOo ensure that hcensees assus and manage increases in r associated with'r'rEtEince actMiiO. "

4[7 ' $ $gg in a series of putslic' meetings, the NRC staff has met with industry representatives to discueEthe change in thdYule'in relation to proposed revisions to NUMARC 93-01, " Industry l

Guideiine for MonitoringfhEEffectiveness of Maintenance at Nuclear Power Plants"' (May

$ A e.avada61e for inspection or copying for a fee from the NRC Public Document Room at 21201. Street NW., l

^D Ethe PDR's mailing addre e is Mail Stop LL-6, Washington, DC 20555; telephone (2021634-3273; fax l

- l This regulatory guide is being issued in dratt f orm to involve the public in the early stages of the development of a regulatory position in this area, it has not received complete staff approval and does not represent an official NRC staff position.

i Public comtreents are being solicited on the draft guide (including any implementation schedule) and its associated regulatory analysis or value/ impact statement. Comments shoulc8 be accompanied by appropriate supporting data. Wntten comments may be submitted to the Rules and Directives Branch, office of Administration, u.s. Nuclear Regulatory Commission. Washington, oC 20555. Copies of comments received may be examined at the NPC Public Document Room. 2120 L street NW.. Washington, DC. Comments will be most helpful af received by Requests for single copies of draf t or active regulatory guides (which may be reproduced) or for placement on an automatic distribution hst f or single copies of future draf t guides in specific divisions should be made in wnting to the u.s. Nuclear Regulatory Commission, Washington, DC 20555, Attention: Reproduction and Distnbution services Section, or by f ax to (301)415-2289. or by imail to < Dis 7RIBUTioN@NRC. GOV >

r.

1993). NUMARC 93-01 was prepared by the Nuclear Energy institute (NEI) and it is endorsed by Revision 2 of Regulatory Guide 1.160, " Monitoring the Effectiveness of iAaintenance at Nuclear Power Plants."2 Partially based on these discussions with industry representatives, this Draft Regulatory Guide DG-1082 is being developed to propose guidance on implementing the provisions of 10 CFR 50.65(e)(4). The final version of DG-1082 is meant to be used with Regulatory Guide 1.160 as guidance on methods acceptable to ti.s NRC staff for assessment processes before maintenance activities to manage the risk from maintenance activities. [

V The information collections contained in this draft regulatory ide are covered by

~

I the requirements of 10 CFR Part 50, which were approved by tho'OfficIof Management

and Budget, approval number 3150-0011. The NRC may not conduct 07'sddns_or, and a'  ;

person is not required to respond to, a collection of information unless it dis'pla s a .-

currently valid OMB control number. - 11^ Y B. DISCUSSION ^

OBJECTIVE l' @

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The objective of the Maintenance Rulei 10 CFR 50.65, isIo iequire monitoring of the overall continuing effectiveness of licensee maintenance progiams to ensure (1) that safety-related and certain nonsafety-related structur'es, cy5tems, and components (SSCs) are capable of performing their intended functions, (2) fo;r noi1 safety-related equipment, that failures wi!I not occur that prevent the fulfillment of safety-related functions, and (3) that f ailures resulting in scrams'and unnecessary actuations of safety-related systems are minimized. / ,

, ba .. - L .s TJe benefits of, performing maintenance activities during power operations include em andplINYriit reliability 27 Eduction of plant equipment and system increase materi5! $'c"ofidi@n deficiMcids tTiat could adversely impact plant operations,

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of work s'cheh$ing plant refuelir@ outages. However, the margin of safety could be l

inadvertent!y' nder'cktinifconditions; for example, if maintenance is performed '

at power wi controiE3nd careful consideration of risk. The intent of 10 CFR licer$ sees perform assessments before maintenance activities 50.65(a)f4fis to re are ' ormed on SSCs cp7ered by the Maintenance Rule and to manage risk that may res' from the propo"ghtivities.d The results of these assessments are to be used in ijunction with oth . regulatory requirements and therefore, cannot be used as ification to perf activities which may not comply with other regulations.

l 2 Single copies of regulatory guides, both active and draft, and draft NUREG documents may be obtained free of charge by writing the Reproduction and Distribution Services Section, OCIO, USNRC, Washington, DC 20555-0001, or by fax to (301)415 2289, or by email to < DISTRIBUTION @NRC. GOV >. Active guides may also be purchased from the National Technical information Service on a standing order basis Details on this l service may be obtained by writing NTIS,5285 Port Royal Road, Springfield, VA 22161. Copies of active and draf t guides are available for inspection or copying for a fee f'om W NRC Public Document Room at 2120 L Street NW., Washington, DC: the PDR's mailing address L, hf ail Stop LL-6, Washington, DC 20555; telephone (202)634 3273; f ax (202)634-3343, i

2

SAFETY ASSESSMENTS FOR MAINTENANCE ACTIVITIES Paragraph (a)(4) of the Rule requires that licensees assess and manage risk that may result from maintenance activities during all modes of plant operation (i.e., including all normal power and shutdown conditions). An appropriate assessment would include a leview of the current configuration of the plant and the plant configuration expected during the planned maintenance activity. Assessing the current plant configuration as well as changes to plant configuration expected from the planned maintenance activities is intended to ensure that the plant is not inadvertently placed in risk'-significant configurations. These assessments do not necessarily require that'ajuantitative assessment of probabilistic risk be performed. The lev,el of detail'withiSch such assessments are performed is expected to vary, based on circumst'aridds'INolved. It g' should be understood, however, that the contribution to risk of a specif((h!$rit]:gg/

configuration depends on both the degree to which the safety functions areiegraded and the duration for which the plant is in that configuration. Furthermore, assessing'the degree of safety function degradation necessitates an uriderstanding of the impact of maintenance activities on the capability of the plant to prevent or mitigate accidents and transients, as well as an understanding of the potentialimpact'of 7 external conditions (e.g., inclement weather, electrical grid instability, flooding or seismic events) on plant maintenance configurations. For multi-unit sites, the assessments should consider the impact of maintenance activities at one plant unit on the other unit (s) and, any common systems shared between units. The asse'ssments m'ap rarige from informed deterministic judgments to the use of an on-line, probabilistic risk assessme'nt (PRA) tool.

,, y The scope of SSCs to be included in the assessments of maintenance activities i

may be limited to those SSCs, i,ndividually.or in combinat on, that can be shown to have a significant effect on the performance of key plan,t safety functions. The focus of the assessmerits should beg on'tlieISSCs niodeled in the licensee's PRA in addition to all SSCs considerMbe risk 4lgM5Et by thilicIs'n'de's maintenance rule expert panel. The assesstheIiit Siiould alsoNOSer combinations of low safety (risk) significant SSCs for pianned E$(intdda'nce that EohldYesult in high safety (risk) significant situat ,

reduce burdhnhJic" es maykb['a one-time assessment to identify low risk-significant SgCh aintenEcje" tivities or combinations of maintenance activities with little or no impact y plant safety functions. j

,i" p 4' An assessme td be reevaluated following the discovery of emergent f ailures hanges in plant cdod ions to determine the safety impact of the failtre or change in

' t conditions. ever, the reevaluation of prior assessments should not interfere

, or delay, th erator and maintenance crew from taking timely actions to restore l ropriateJS to service or taking compensatory actions necessary to ensure plant

(  : s mainjaTned, if the SSC is restored to service before the assessment is T=]mpwe evaluation need not be conducted.

The process for performing these assessments should be scrutable and repeatable.

Known limitations in the assessment process should be described in the licensee's assessment process in accordance with 10 CFR 50.65(a)(4) that is part of the maintenance rule program documentation. The licensee's maintenance rule expert panel l should review this process to ensure that the process is sufficiently robust and comprehensive.

3 i

C. REGU_LATORY POSITION

1. ASSESSMENTS FOR MAINTENANCE ACTIVITIES DURING POWER OPERATING CONDITIONS Licensees should perform assessments of maintenance activities planned to be implemented durirg power operating conditions. Power operating conditions are defined as plant modes other than a hot shutdown, cold shutdown, refueling, or defueled condition. E 6 gs

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This guidance should be applicable to the two methods commonly used to evaluate the risk impact of plant maintenance configurations: (1) using a pfani"riik*[nonitor" (a v computer based risk analysis tool) and (2) using a matrix of pre-analyzed plid1t$g;/'

configurations. Most plant risk monitors are customized to evaluate the risk impact of mantenance activities on SSCs used to mitigate events, as well as SSCs that may initiate everes (e.g., switchvard maintenance). The adequacy an'd q'uality of this assessment tool depends on the fidelity of the PRA model and the accuracy 'of the input assumptions. It is expected that the scope of the PRA modelin a plant risk n%nifor^should reflect the "as-built, as-operated" plant configuration to limit the underestimatioEof risk associated with maintenance configurations. Additionally, full requantification}$the'r than cutset editing) of the PRA model for the assessment of each maintenance configuration is desirable to

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ensure a greater fidelity of results when' multiple components are involved.

.:l >y7 If a matrix of pre-analyzed, plant configurations is used for the assessment, the limitations of the risk matrix should'be clearly identified and the users of this tool should have sufficient knowledge and fa'miliarity with the tool's limitations. The adequacy of the safety assessment tools.should be evaluated by the licensee's expert panel to determine the possible li describe'dTn# mitations.aThe known limitations of the assessment tool should beth limitatiiiriis shou,ld he provididih N5 k!:'jh The de f YN[h should be com[tajlf mensurategwith assessmen,t;for evaluating ttkcomplexity of the theThe configuration. risk of ofa detail level maintenance config g

and attrit$iifs~oTtM$lessment'for

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evaluating increases in risk arising from maintenance duringyower operat'iN[8o"n'.ditions are as follows.

'e #

Maintenance A~ctivity on a Single SSC (simple SSC)

(1) If the; planned maintenance configuration consists of one simple SSC or one SSCTtrain only, qualitative assessment based on the informed judgment of a as y$ned licensed operator is sufficient to evaluate the safety impact of the maintenance activity on the simple SSC or SSC train. A simple SSC is one SSC with no interactions or dependencies with other key piant safety functions.

1 (2) The operators making the informed judgment should be knowledgeable of I the SSC's contribution to plant risk, or which key safety functions are  !

degraded by the maintenance on the SSC. {

4

7 (3) The licensee's assessment process should contain provisions to evaluate the safety impact when emergent failures, changes in the plant, or changes in external conditions occur.

(4) The operators should be aware of the potentialimpacts of external conditions (e.g., inclement weather) and other activities (e.g., switchyard maintenance) that may increase the hkelihood of an initiating event.

1.2 Maintenance Activities on Two SSCs +

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(1) If the planned maintenance configuration consists of'any two_SSCs, either a qualitative or quantitative assessment should be useSloImins'ge changefin risk to ensure that the plant is not inadvertently ' placed in a risk-significa'nt configuration or in conditions that w'ould degrade the perform'an'es"$f blant safety functions.

(2) The licensee's assessment process should establish guidelines for managing risk, that is, the process should specify the levels of risk that would require ]

certain actions (e.g., management approval, or contingency planning).  !

n, L (3) The assessments may be based on evaluations of predetermined

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configurations (e.g., va(iou's combination's'of-tw/SSCs), or the assessments could be performed'on an a'$-i1%ded basis.

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f' (4) The licensee's assessment process should contain provisions to evaluate the safety impact when emergent failures, changes in the plant, or changes in external conditions occur.

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,J%,s.Wconfigurations licensee'h sl process not should contain provisions to ensure that plant recognized by the assessment tool are evaluated by

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%?p%jopriate personne(such as a risk analyst or the expert panel. This sex tation doesmot apply to those combinations of two SSCs that were

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. 4 to,_lp ridf W!gb 1.3 Maintenance ActM,tiss on More Than Two SSCs

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(1) Ift f lanned maintenance configuration consists of more than two SSCs,

.the%ssessment should be strongly focused on risk insights derived from PRA analyses.

) The assessments may be based on evaluations of predetermined configurations (e.g., various combinations of multiple SSCs), or the assessments could be performed on an as-needed basir.

(3) The licensee's process should contain provisions to ensure that plant I configurations not recognized by the assessment tool are evaluated by appropriate personnel such as a risk analyst or the expert panel. This expectation does not apply to those combinations of multiple SSCs that l

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. i were determined through a one time assessment to have little or no contribution to plant risk.

(4) The licensee's safety assessment process should establish guidelines for managing risk, i.e., the process should specify the levels of risk increase

. that would require certain actions, e.g., management approval or j contingency planning. ,

s (5) The licensee's assessment process should contain proIrisions to evaluate )

I the safety impact following emergent failures or chariges,(in, plant conditionf.

af ter the assessment of the planned configuration. -

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2. ASSESSMENTS FOR MAINTENANCE ACTIVITIES DURING SHUTDOWN OT i CONDITIONS .,

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The performance of safety assessments for maintenance activities during shutdown conditions involve the same general guidance as described abover However, there are <

some considerations that are different than for power operatf$rYc'o'h$itions. Sophisticated quantitative assessment tools are not generally available, as PRA[models for shutdown plant conditions are not widely used. If.a PRA modelis not available, an assessment of l degradation of the key safety functions for shutdbiNNedMitiorE should be made for any I maintenance activity on the in-scope SSCs. p> l

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Key safety functions for shutdown conditions are decay heat removal capability, reactor coolant inventory control, electrical power availability, reactivity control, and containment closure (primary and secoridary). As'sessments for shutdown maintenance

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activities thust take into'adc$unt outage conditions and plant configurations that impact key safe $nctions/F$r7eNi'mple, assehNdbht of maintenance activities that impact the decay'bfatTefdoval ca'psbiliyshould consider these key aspects:

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• %niti (pagnitudeLof becay heat

• a'ctor c t boiling we Time to uncover the core y

. Time to achieve containment closure AY e ini reactor coolant system inventory condition (e.g., filled, reduced, "idioop, refueling canal filled, reactor cavity flooded)

. Reactor coolant system configuration (e.g., open or closed, nozzle dams installed or loop isolation valves closed, steam generator manways on or off, vent paths available, temporary covers or thimble tube plugs installed, main steam line plugs installed)

+ Natural circulation capability with heat trnsfer to steam generator shell side

. Instrumentation needed to monitor the conditions 6

a Additional aspects of the fuel handling and core alteration activities should be considered. These considerations should address systems needed to mitigate fuel handling accidents such as radiation monitoring and ventilation and filtration systems. In addition, spent fuel cooling capability should be considered.

3. RISK SIGNIFICANT CONFIGURATIONS j A risk-significant configuration is (1) a configuration of concurrent equipment outages for which the incremental contribution to the annual risk is sbWstantial or (2) a configuration that would significantly affect the performarice of safhy}iinct, ions. Because the risk of equipment-outage configurations depends on the maintenance configuratio.n?

and duration of the configuration, the risk metrics for evaluating the riif$ighificance"of a plant configuration should be estimated increases in core damage probabilitydCDPfor large early release probability (LERP). The CDP (or 1.ERP) is,the integration of expected core damage frequency (or large early release frequency) over.a specified time interval. j Regulatory Guide 1.174, "An Approach for Using Probabilistic, Risk Assessment in Risk-  !

Informed Decisions on Plant-Specific Changes to ttie Licensing lBa' sis,"2 provides risk-acceptance guidelines for allowable smallincreases above the plant 6aseline CDF (or LERF) for a permanent plant change, whereby the all6iived increases 'rsusibe consistent with the intent of NRC's Safety Goal Policy Statement? The NRC. staff's position is that an I equipment-outage configuration becom'es risk si@iifidn$ hen *t'he increase in CDP (or l LERP) exceeds a pre-determined levelc V

_, ,/ ll' Because of variations in risk profiles,between nuclear plants, quantitative screening criteria for risk-significant configurations should be established on a plant-specific basis to reflect the plant risk profile. For temporary. risk changes associated with equipment-outage configurations, relative criteria could bdSied on a sliding scale to determine risk significQ{opase CD(( aides less tlsad$1'E 4/yr I and base LERF values less than 1E-5/yr.

The temporarycnsk-acceptance criteria should be based on increases in CDP (or LERP) that account fo(ridl Montributio'n'thIst'is due to the duration of the configuration. If the base CDF value ofyl exceeding ercent' *at10a'yhin thelaEfeVetween increase in $he 1E-5 CDP (or LERP) estimate could and to1E-4/yr, a relati be selected signIficant demarcation for a given configuration. If the base CDF establish:thYnon value Tthe plant is'b $sE[klo@E-5/yr, a relative change not exceeding in CDP (or LERP) $ stimate could be used. This approach would limit the cumulative mpact of all equipfndnt-outage configurations to low CDP values, i.e., less than 1E-6.

s, a threshold probability of 1E-6 could be used as the criterion for determining the risk ficance of a plant maintenance configuration.

AUK AND SOPHISTICATION OF SAFETY ASSESSMENTS he quality and sophistication of the safety assessment tools are important to assure appropriate analyses of plant configurations for risk management purposes. The assessment tools should be of sufficient quality to identify risk-significant configurations.

If the assessment toolis a plant-specific PRA, the PRA model used for evaluating plant-configuration risks should reflect the "as-built and as-operated" plant. In addition, the quality of PRA models and assumptions used for this analysis should reflect the current industry practices of achieving meaningful PRA results. Thus, the FRA model and its database should be updated when necessary to account for plant design modifications and 7

(. .c changes in operational practices and equipment rehability. This ensures that the quantitative assessment results adequately reflect the modeled contributors to risk.

5. MANAGING RISK The assessments provide insights to identify and limit risk-significant maintenance activities and their duration. The process for manag:ng risk of maintenance configurations includes identifying, assessing, and controlling risk increase resulting from maintenance activities. This process should include an understanding of the nature (i.e!, affecting the core damage, or large early release frequency) and significance of the risk implications of a maintenance configuration on the overall plant baseline' risk levelf 'Abioiclingly, risk-significant plant configurations should generally be avoided , as sh6'uldEoIiditions where'a key safety function would be significantly degraded while conducting maintenance-1' activities. The risk of maintenance activities may be controlfe'd by defining ths risk'I^

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increase levels (e.g., high, medium, or low increase) so that appropriate actions (e.g., shift manager alert) are taken. The effective control of potentially significant risk increase due to an unexpected f ailure of another risk important SSC can be reasonably assured by planning for contingencies, or coordinating, scheduling, monitoring, and modifying the duration of planned maintenance activities. If there is a net safety. benefit of performing l maintenance on a proposed configuration during power operation r'ather than at plant

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shutdown condition, where the proposed configuration may have an expected high risk increase for a short duration, the licensee should implement thEfollowing:

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• Duration of the maintenance activity should be minimized through preplanning and prestaging necessary equipment.

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• Plant management approval should be obtained before entering the j p configuratidk.% , b  !

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@mpensatoryjactions and contingency plans should be implemented if j

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.q' Site personnel should be at a heightened state of risk awareness while the p aIU(is[dnYi$le safety 9 risk-significant is significantly degraded, configuration or in a condition in whi implementing eb practices is a prudent approach to ensure that the risk of ntenance activiti Yinvolving potentially risk-significant configurations is effectivery ged, r i

j D. IMPl.EMENTATION The purpose of this section is to provide information to licensees and applicants regarding the NRC staff's plans for using this regulatory guide.

This draft regulatory guide has been relesed to encourage public participation in its  !

development. Except in those cases in which a licensee or applicant proposes an acceptable alternative method for complying with necified portions of the NRC's regulations, the method to be described in the active guide reflecting public comments will 8  !

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a be used with Regulatory Guide 1.160 in the evaluation of assessment processes before

maintenance activities to manage the risk from maintenance activities.

REGULATORY ANALYS:S The Regulatory Analysis that was published with the rulemaking for the amendment to the Maintenance Rule,10 CFR 50.65(a)(4), is also applichble for this Draft

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Regulatory Guide DG 1082. A copy of the regulatory analysis is available for; inspection or

- copying for a fee in the Commission's Public Document Rooma' t 2120 L Street NW.,.

Washington, DC, under task DG-1082,.

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