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UNITED STATES
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NUCLEAR REGULATORY COMMISSION WASHINGTON, o. C. 20555
%' v "l October 16, 1990 f
MEMORANDUM FOR:
James M. Taylor Executive Director for Operations FROM:
Edward L. Jordan, Chairman Committee to Review Generic Requirements
SUBJECT:
RESOLUTION OF GSI B-56, " DIESEL RELIABILITY" At Meeting No.190, the CRGR reviewed and endorsed (with several caveats) the i
proposed GSI B-56 resolution, which included proposed final Revision 3 to Reg.
Guide 1.9 and a proposed implementing generic letter.
The final form of the Reg. Guide revision endorsed by CRGR contains guidance for monitoring and main-taining emergency diesel generator (EDG) reliability, including detailed guid-ante on EDG reliability programs.
Overall EDG reliability performance in the operating plants is currently acceptable as a result of industry /NRC efforts during the last few years; but published guidance such as that con-tained in Rev. 3 to Reg. Guide 1.9 is needed to assure that each individual operating plant achieves an acceptable EDG reliability level, and to maintain overall EDG reliability performance at the current level.
i The NRC staff and NUMARC worked in a closely coordinated effort for nearly two years to develop such guidance.
As a result, the staff came to regard a pro-posed industry guide (NUMARC 87-00, Appu tix D) as a viable means of providing the regulatory guidance needed in this area.
The staff relied on that docu-ment in proposing for CRGR review a version of Rev. 3 to Reg. Guide 1.9 which referenced extensively the NUMARC guidance.
In its review of that proposed Reg. Guide in Meetings 171 and 176, CRGR urged the staff to adopt the NUMARC guidance with minimal exceptions or embellishment.
The staff was proceeding on that basis until recently when (in a May 3 letter, W. Raisin to E. Beckjord)
NUMARC withdrew its detailed EDG program guidance, based on the contention that the EDG reliability problem was solved.
The staff was faced with a potential temporary resolution of GSI B-56, if it declared the issue resolved withcut issuance of lasting guidance or publication of NRC stand-alone guidance.
The CRGR strongly supports the staff's final proposed action to publish Rev.3 to Reg. Guide with stand-alone guidance for monitoring and maintaining EDG reli-ability, including detailed guidance on EDG reliability programs attached as an Appendix to the Reg. Guide.
The CRGR is conce ned that NUMARC's action in withdrawing guidance that the staff had planned to rely on as an industry standard reflects a breakdown of cooperation by NUMARC with the staff that may affect future similar activities.
You may wish to raise these concerns in your periodic discussions with NUMARC management.
Clearly, as a result of this experience, the CRGR will be reluct-ant to urge the staff to adopt or rely on NUMARC guidelines in future resolu-tions.
9306170146 930422 hR 57 14514f PDR O'
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Enclosure A (and its attachments) provide a more detailed discussion of this~
matter and the specific circumstances that led to this expression of Committee concern.
If there are-any questions regarding these CRGR views, I will-be happy to discuss them with you further.
I Original Signed by:
E. L Jordan Edward L. Jordan, Chairman Committee to Review Generic l
Requirements
Enclosure:
As stated CC:
l T. Murley E. Beckjord i
Distribution:
CRGR Members i
W. Minners A. Thadani
~
P. Norian A. Serkiz i
D.Ross J.'Conran D. Allison M. Taylor
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OFFICIAL RECORD COPY t
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t Discussion of CRGR's Review of the Proposed Resolution for GSI B-56 and the Circumstances Surrounding NUMARC's Withdrawl of EDG Program Guidance from NUMARC 87-00, Appendix D At Meeting No. 190, the CRGR reviewed and endorsed (with several caveats) the proposed GSI B-56 resolution, which included proposed final Revision 3 to Reg.
i Guide 1.9 and a proposed implementing generic letter.
The final form of the j
proposed Reg. Guide revision endorsed by CRGR contains detailed guidance on emergency diesel generator reliability programs.
NUMARC objected to the pre-i scriptiveness of the proposed guidance in comments submitted formally to the NRC staff and CRGR (Attachment 1).
NUMARC expressed the view that detailed i
regulatory guidance on EDG reliability programs is unnecessary now, in view of the overall high EDG reliablity (in the range 97%-98%) achieved as a result of NUMARC/ industry initiative in this area.
NUMARC also expressed the concern that detailed EDG reliability program' guidance will be misused by the staff, with the result that undue emphasis will be placed on programmatic aspects j
rather than on reliability performance.
The CRGR considered these points in detail in discussions of the B-56 issue at Meeting No. 190 and, despite the objections raised by NUMARC, endorsed attachment of detailed EDG reliability program considerations in an Appendix to Reg. Guide 1.9 as discussed in item 3.
below.
The rationale for the Committee's action is discussed below.
1.
Although "overall" EDG reliability performance for the operating plants '.s currently at 97%-98% according to industry data, each year individual plants have remained below the minimum 95% level specified in Reg. Guide 1.155 (the regulatory guidance approved for implementing 10 CFR 50.63, the Station Blackout rule).
This is displayed graphically in Attachment 2.
For individual plants that do not voluntarily implement programs capable of achieving and maintaining the minimum expected EDG reliability level, there is a legitimate regulatory need for detailed EDG program guidance i
that can be brought to bear effectively to achieve needed performance improvement.
Ideally, such guidance is found in industry standards that can be referenced to serve the regulatory purpose.
In this case, however, despite extensive efforts by the staff to encourage and work with NUMARC in developing such a standard, no detailed industry guidance for EDG programs is now available to reference in this manner.
In these circum-stances, CRGR considers it a normal, prudent regulatory course of action for the NRC staff to issue their own stand-alone regulatory guidance as proposed in the B-56 resolution package.
2.
The NUMARC argument that regulatory involvement is simply not needed now in the EDG guidance area might carry more weight if the nuclear industry l
truly had, on its own initiative, recognized and ef fectively dealt with l
the EDG reliability problem.
It is misleading for NUMARC to imply, as i
they have in the formal comments submitted to NRC, that the improvement achieved in overall'EDG reliability over the last few years is primarily the result of industry /NUMARC initiative.
The regulatory need for EDG reliability improvement was identified by the NRC staff in defining USI A-44 and GSI B-56.
In proper context, therefore, the industry efforts to T
improve EDG reliability are not.the result of industry initiative in this (j
area, but are more accurately characterized, "in part" or "in toto" as a response to an identified regulatory need articulated by NRC.
Enclosure A g = = -
9' P-P-T%
. Further, the current overall EDG reliability performance levels cited by NUMARC were achieved by licensees implementing EDG reliability programs that followed guidance provided by NUMARC (i.e, NUMARC 87-00 Appendix D).
That guidance was developed by NUMARC in close consultation with the NRC staff following issuance of the Station Blackout rule, 10 CFR 50.63.
[ Attachment 3 provides indication of the extensive NUMARC/NRC staff inter-actions that occurred, and the unusual amount of CRGR review effort that was expended, during the course of that guidance development effort.]
The Appendix D guidance that evolved as a result of that effort reflected proven good practices among the more successful utilities; and, until very recently, it included detailed EDG program guidance.
The staff believes that program improvements made by poorer performing licensees in imple-menting that guidance were a major factor contributing to the improvement of overall EDG reliability levels over the past few years. The staff also believes that the expectation that NRC would endorse / adopt such guidance, as the regulatory basis for evaluating the EDG programs of licensees who do not achieve and maintain acceptable EDG reliability levels, provided a strong incentive for the weaker licensees to voluntarily implement the Appendix 0 program guidance and improve their performance.
NUMARC's turnabout action (in May of this year) removing that program guidance from Appendix D, and putting it in a topical report not submitted for staff review, effectively places that guidance beyond regulatory scrutiny and application for regulatory purposes.
That could have the effect of removing the incentive for those licensees to continue implementing the guidance.
In any case, NUMARC's action cerainly makes less clear the industry's commitment to NRC to continue to apply proven effective program guidance in these areas.
Under these circumstances, the Committee believes that the proposed staff 1
approach of issuing stand-alone regulatory guidance, sufficiently detailed for use in identifying program weaknesses and specifying corrective meas-i ures if reliability performance falls below acceptable levels, is the prudent regulatory course in this mattter.
3.
With regard to NUMARC's stated concern that detailed EDG reliability program guidance would be subject to misuse, and would result in inappropriate emphasis on programmatic aspects to the detriment of reliability performance if included in Appendix D or other regulatory guidance, the Committee also recognized this potential and addressed it explicitly in the discusssion of the B-56 issue with the staff at Meeting No. 176.
(See Attachment 4, Recommendation 7.) The staff responded to i
this potential concern by redrafting proposed Revision 3 to Reg. Guide 1.9 and its implementing generic letter, to move prescriptive guidance prev-iously included in Regulatory Positions (e.g., EDG surveillance plan, performance monitoring, diesel maintenance program, failure analysis, root cause investigation) into an Appendix to the Reg. Guide.
Also, the the language of the proposed Reg. Guide and the proposed implementing generic letter was revised to make clear that (1) information contained in the new Reg. Guide Appendix should not be treated as Regulatory Positions, but should be understood as considerations and illustrative examples that reflect current good practices; and (2) licensees do not have to replace
)
or revise current practices that are proven effective by good EDG reli-1 sj ability performance.
. The Committee expressed in the minutes for Meeting No.190, its dismay 4.
over the recent NUMARC action removing from the Appendix D document much of detailed guidance previously included.
That action by NUMARC followed several years of effort by the HRC staf f to develop, in cooperation with NUMARC, complementary detailed EDG guidance (specifically, Revision 3 to Reg. Guide 1.9 and the NUMARC Appendix D document).
As a result of those coordinated efforts, the NUMARC Appendix 0 guidance reviewed by CRGR at Meeting No. 176 was judged to be a fully acceptable equivalent to the detailed guidance in the staff's proposed Revision 3 to Reg. Guide 1.9.
At that point, the Committee recommended, and the staff agreed in princi-ple, that Appendix 0 should be adopted (essentially with out exception) as an industry standard, suitable for-referencing and use by the licensees as acceptable means for monitoring and maintaining EDG reliability.
The staff informed NUMARC of this planned endorsement of Appendix D guid-ante by HRC.
NUMARC then chose to revise Appendix D and remove much the detailed EDG program guidance that had made it suitable for referencing in the Reg. Guide.
That action by NUMARC at this late stage rendered largely a waste the expenditure of significant staff resources (and CRGR review effort) over the last year-or-more.
In addition, this has resulted in a year-or-more of unnecessary delay in coming to regulatory closure on the B-56 issue (in the manner currently proposed by the staff),
Beyond these immediate practical concerns relating to the B-56 issue specifically, the withdrawl of detailed guidance developed on a cooperative basis with NRC raises questions regarding the reliance NRC should place on NUMARC in any other future issue resolution effort; and this experience should be kept clearly in mind in deciding future NRC interactions with NUMARC. - After this experience, the CRGR will be reluctant to urge the staff to adopt or rely on NUMARC guidelines in the future.
The Committee's believes that this development is of sufficent concern that it may be an appropriate item to raise in the ED0's periodic discussions with NUMARC management.
i 1
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l RESOLUTION OF GSI B-56 i
PRESENTATION TO THE ADVISORY l
COMMITTEE ON REACTOR SAFEGUARDS i
August 9,-1990 W. Minners RES/DSIR MS NUS 360 EXT. 23900 l
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B-56 RESOLUTION CHRONOLOGY SBO RULEISSUED 6/88 CRGR MTGS NO. 144 & 146 8 & 9/88 RG 1.9, REV. 3 ISSUED FOR COMMENT 11/88 COMMENT PERIOD CLOSED 3/89 MTGS WITH NUMARC (7 MTGS) 5-6/89 l
CRGR MTG NO.164 6/89 MTGS WITH NUMARC (4 MTGS) 7-10/89 CRGR MTG NO.171 10/89 CRGR MTG NO.176 12/89 l
ACRS MEETING 2/90 DISCUSSIONS WITH NUMARC 1-3-90 NUMARC SUBMITTAL OF INITIATIVE 5A &
l NUMARC-8700, APPENDIX D 5/90 CRGR MEETING 190 7-25-90 ACRS MEETINGS SCHEDULED 8-8-90 8-9-90 l
Slide 2
1
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OVERVIEW RG 1.9, REV. 3 i
1.
Consolidates into a single RG -guidance previously provided in RG 1.9, Rev. 2, RG 1.108 and GL 84-15, thereby minimizing regulatory confusion.
2.
Better defines testing requirements, eliminates cold fast starts and limits accelerated testing to the
" problem" EDG.
3.
Provides common guidance for monitoring EDG reliability levels and actions to be taken.
4.
Defines the elements of an. EDG-reliability program
.and provides illustrative examples of proven-considerations and practices; supplements guidance provided in RG 1.155, " Station Blackout".'
5.
Incorporates proven industry practices and is-
~
consistent with NUMARC's Appendix D (5-2-90) and related Topical Report.
6.
Provides specific. guidance for use by the staff or.
industry to review the adequacy of diesel generator reliability programs consistent with the resolution of USI A-44.
Slide 3
9 (7-23-90)
TABLE 1 CROSS-REFERENCE BETWEEN REGULATORY GUIDE 1.9, REV. 3 AND NUMARC-87-00, APPENDIX D (5-2-90)
RG 1.9,REV 3 NUMARC-8700 SECTION APPENDIX D Section A, Introduction None (Use RG 1.9,Rev.3)
Section B, Discussion None (Use RG 1.9,Rev.3)
Section C, Regulatory Position 1 Design Considerations None (Use RG 1.9,Rev.3) 2 Diesel Generator Testing 2.1 Definitions D.1 2.2 Test Descriptions None (Use RG 1.9,Rev.3) 2.3 Preoperational and Surveillance Testing None (Use RG 1.9,Rev.3) 3 EDG Reliability Goals and D.2 Monitoring 3.1 Reliability Goals for SBO Introduction 3.2 EDG Reliability Monitoring D.2.2, D.2.3 3.3 Maintaining EDG Reliability D.2.1,D.2.3,D.2.4,D.2.5 3.4 Problem EDG D.2.4.4 4 Record keeping Guidance D.2.4.6 5 Reporting Criteria Use RG 1.9, Rev. 3 6 EDG Reliability Program Introduction 6.1 Monitoring EDG Reliability D.2 l
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- 6. 3 :; EDG - PerformanceiM,onitbring b fNone[(Use7RG11.9,Rev.3):
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9None k(Usel RG;;fij 9,Rev. 3) 6'. 5 ; EDG n Failure.l:. Analysis ? and f f Nones (UseiRG;.z1; 9)Rev. 3) i
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i RootDCauseCInvestigation
- 6. 61 EDGf Problem 9 Close-out'.-
INone?(UseTRGfli9,RevJ3) 6.7;EDGfReliabilitylDataISystem.,
e None.[(Use s RG L 1. 9,Rev ; 3 )
l l
Section D, Implementation Introduction (Initiative 5A)
Slide 4 i
l 4
i I
l C.6 EDG RELIABILITY PROGRAM i
i Section C.6 Identifies the followirig principal elements of an EDG reliability program:
~
1.
Monitoring nuclear unit EDG reliability l
levels against SBO targets.
2.
Surveillance Plan j
3.
Performance monitoring of important i
parameters.
1 l
4.
Maintenance Program 5.
Failure Analysis 6.
EDG Problem Closeout Process -
7.
EDG Reliability Data System These elements are the same as NUMARC's.
i The RG subsections which follow provide general guidelines (with illustrative examples) for these major program elements.
Slide 5
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Probability 1
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Probability 0.9
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l EDG RELIABILITY 1.
EDG reliability situation has improved i
3 j
2.
Industry reported " Averaged" level is l
97 - 98%; the staff has not independently
)
verified this finding.
l 3.
Annual plant performance data shows a j
small number of plants sliding below 95%.
i j
4.
Plant specific EDG maintenance problems continue to exist despite reported high i
levels of EDG reliability (e.g. VOGTLE, COOPER, DC COOK, CALVERT CLIFFS, ZION) l 5.
The NRC relies primarily on industry l
reported EDG performance and availability.
i l
i i
i Slide 10 i
4 a
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j Diesel Generalor Total Unreliability (by station)
Industry herage l
0.050-0.040-1 0.030-0.020-
.un uld un un c.0to-ik ik ilo ik l
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i Diesel Generator To!al Unreliability (by station)
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(1/86 - 12/88) l Best Quor!Be Wedian 20-l I4 l
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l Ref. 5/2 3/89 meeting with NUMARC B-56 Working Group Slide 11 i
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Figure 4.3b Histograms showing emergency diesel generator l
failure on demand for 1983 through 1985 l
l NUREG-1032 4-8 I
Slide 13
Diesel Generator 1o101 Unreliability (by statica)
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Ref. 52-3/89 meeting with NUMARC B-56 WoMng Group Slide 14
l PLANT SPECIFIC EDG PERFORMANCE I
l l
o LERS o
Special Reports - Tech Specs RG 1.108, Rev. 2 Approx 50% of plants need to report l
i o
llT (Vogtle llT Report)
EDG1A 4 failures in last 93 demands l
EDG1B 6 failures in last 84 demands l
EDG2A 5 failures in last 87 demands EDG2B 0 failures in last 32 demands l
i o
Calls to Resident inspectors o
INSPECTION REPORTS l
i Slide 15 l
I
?
L l
l Voatie EDG Maintenance issues i
o Calcon temperature sensors malfunction caused DG failure & resulted in station black-out.
o Calcon sensors have been a long standing problem.
Approx. 70 sensor failures reporting during plant history (*).
Only about 5 failures entered into NPRDS.
l Sensor history was not factored into-EDG maintenance program; i.e., there was-no trending associated w/ sensor performance, nor was there-any changes to sensor maintenance as a consequence of failures.
IIT did not obtain historical data on sensors until 6 weeks into the inspection-material was very difficult to retrieve.
(*) All historical data may not have been retrieved, & there may have been more than 70 failures of sensors.
o Vogtle maintenance program for EDGs did not identify temperature sensors as a significant contributor to potential EDG failures - a well organized & functioning program would have done so.
o NPRDS data is inaccurate because of questions regarding what needs to.be reported (see above).
o Failures which occurred during post maintenance
)
testing were not entered into NPRDS, nor were they
)
factored in Vogtle Maintenance Program.
o Vogtle was not aggressive regarding EDG problems.
(see NUREG-1410)
/
l-Slide 16-l
1 i'
Cooper EDG Maintenance issues o
Special NRR inspection team noted significant deficiencies in EDG maintenance program.
Maintenance program deficiencies noted in
~
Inspection Reports 89-11 & 89-12.
o inadequate EDG maintenance program resulted in one EDG being effectively inoperable for an extended period of time.
i Licensee was cited for a Level 111 violation as a consequence of the above noted EDG condition.
D.C. Cook EDG Maintenance issues o
Engine overspeed caused failure of a generator & some damage to diesel engine.
o Overspeed caused by improper adjustment of fuel racks on individual cylinders.
Periodic adjustment of racks to balance engine on the. basis of cylinder exhaust temp.
l No evidence of any investigation as to why l
cylinder temperatures varied from one time period to another.
No evidence of use of prior adjustment data as an input to current adjustment requirements.
l No evidence of test & calibration of exhaust temp.
j indicators.
l Slide 17 i
l
'l
=
D.C. Cook EDG-Maintenance issues-(Cont) o Licensee was given poor SALP rating in the area of maintenance - due primarily to inadequate Root Cause determination associated with DG overspeed event.
o Licensee did not investigate the cause of certain anomalies on parts removed from the diesel engine -
anomalies in this case meaning not consistent physical damage expected from a DG overspeed event.
o Corrective actions did not include significant changes to any of the above noted undesirable conditions.
Calvert Cliffs EDG Maintenance Proaram o
Diagnostic inspection Team observed maintenance activities associated with DGs.
o Team inspection did not specifically evaluate.the programmatic aspects of DG maintenance, but team did observe problems with the conduct of maintenance activities.
Team observations or findings are documented in inspection Report 89-200.
o Team member responsible for maintenance observations believes that past history was not used as an input when determining current maintenance activities.
o Poor execution is an indication of serious programrnatic deficiencies.
Slide 18
ZION EDG MAINTENANCE INSIGHTS o
Observations regarding EDG maintenance (by. Region 111 &
Contractor personnel)
Trouble shooting of EDG problems is not conducted in an organized manner using detailed procedures and instrumentation.
It could not be determined how many, if any, of the Zion mechanics assigned to work on EDGs had formal training.
No specifics were available regarding what constituted.
"On-the-Job" training & how much each mechanic received.
Mechanics are assigned to EDG maintenance based on.
their exposure levels in " hot" areas of the plant, and not on the basis of knowledge; e.g. - there is no dedicated EDG maintenance staff.
Maintenance procedures are poor.
o Above observed deficiencies were responsible, in part or in total, for 15 failures to start during surveillance testing or trouble shooting in Feb. & March,1990.
o Observations are consistent with negative findings regarding other maintenance activities at Zion by a Maintenance inspection Team and a Diagnostic Team.
UNDERLYING CAUSES 1)
Inadequate root cause analysis.
2)
Failure to incorporate operational experience (on-site and from other plants) into EDG maintenance activities.
3)
Failure to utilize engine parameters for trending purposes.
1
.4)
In-effective problem close-out and lack of verification of effectiveness.
Slide 19
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1 50.54(f) LETTER
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(Enclosure C, CRGR Pkg) 1)
WHY NEEDED?
a.
NUMARC initiatives and guidelines are not a i
license commitment.
2)
WHAT IS BEING REQUESTED?
i a.
Plans and schedule for complying with:
o NUMARC Initiative SA and Appendix D (5-2-90) l o
RG 1.9, Rev. 3, Sections C.3, C.4, C.5 and C.6 l
- OR -
o identification of the portions of the initiative and the Reg. Guide which will not be implemented and the basis therefore.
l b.
Licensees may request changes in Plant Tech Specs t
to reflect actions which would be implemented.
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Slide 20 l
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SUMMARY
OF CRGR MTG 190 (Minners to Fraley 7/27/90) l l
1)
RG 1.9, Rev. 3, Section C.6 will be reduced in l
scope. Section C.6 and C.6.1 will remain in the main body of the RG. The illustrative examples and considerations contained in Sections C.6.2, C.6.3, C.6.4, C.6.5, C.6.6 and C.6.7 will be placed into an appendix.
2)
The 50.54(f) letter will be revised to more clearly note that NRC is requesting a response as to j
whether licensees plan to implement guidance provided, or to identify actions utilities plan to implement for monitoring and maintaining EDG reliability and to identify the type of reliability program to be used in support of maintaining required levels of performance.
i 3)
A formal reply will be prepar'ed in response to NUMARC'S comments.on RG 1.9, Rev. 3.
l Slide 21 i
p
i t
RESOLUTION ACTIONS PENDING t
- 1. Issue RG 1.9, Rev. 3
- 2. Issue 50.54(f) Letter
- 3. Close out GSI B-56 based on items 1 & 2
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Slide 22 I
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E NUCLEAR UNITED STA TES
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ADVISORY COMMITREGULATOR Y 4604 -l TEE ON RE COMMISSION WASWNGTON, O ACTOR SAFEGUARDS
.C 20555
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ChairmanThe Honorable 14, 1990 i
WashingtonU.S. Nuclear R Kenneth
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Dear Chairman20555 ssion
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SUBJECT:
Carr*
PROPOSED During GENERATORRESOLUTION RELIABILITY" GENERIC OF the Safeguards 364th SAFETY resolution,oAugust meeting of ISSUE Reliability "f B-56, Generic Safet9-11, 1990 the Advisory
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4y ADVISORY COMMITTEE ON REACTOR SAFEGUARDS 4
WASHINGTO.J, D. C. 20555
.....e August 14, 1990 The Honorable Kenneth M.
Carr Chairman U.S.
Nuclear Regulatory Commission Washington, D.C.
20555
Dear Chairman Carr:
SUBJECT:
PROPOSED RESOLUTION OF GENERIC SAFETY ISSUE B-56, " DIESEL GENERATOR RELIABILITY" During the 364th meeting of the Advisory Committee on Reactor Safeguards, August 9-11, 1990, we reviewed the NRC staf f's proposed resolution of Generic Safety Issue (GSI)
B-56,
" Diesel Generator Reliability."
Our Subcommittee on AC/DC Power Systems Reliability also reviewed this matter during a meeting on August 8,
1990.
During these reviews, we had the benefit of discussions with representatives of the NRC staff and of NUMARC.
We also had the benefit of the documents referenced.
In our
- view, this proposed resolution includes unjustified imposition of maintenance requirements on the licensees, in contravention of the Commission's decision to defer issuance of a maintenance rule pending assessment of licensees' maintenance programs.
The proposed resolution of GSI B-56 involves two steps.
- First, Section C.6 of proposed R.G.
1.9, Rev.
3, contains an explicit example of a diesel generator reliabi]ity program, including maintenance, with detailed checkoff and corrective action lists.
Second, the staff proposes to require adoption of R.G.
1.9, Rev.
3, by a generic letter pursuant to 10 CFR 50.54(f).
As background, GSI B-56 is related to the Station Blackout Rule (10 CFR 50.63).
The staff issued R.G.
1.155, " Station Blackout," to provide guidance for compliance with this rule.
R.G.
1.155 identified the need for a reliability program to achieve and maintain diesel generator minimum reliability levels of 0.95 or 0.975 per demand, depending on the blackout duration coping requirements calculated for a particular plant.
R.G.
1.9, Rev.
3, provides guidance for a reliability program by integrating into a single regulatory guide pertinent guidance now addressed irf G.
1.9, Rev.
2, R.G.
1.108, Rev.
1, and Generic U
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The Honorable Kenneth M.
Carr
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August 14, 1990 3
Letter 84-15.
In addition, R.G.
1.9, Rev 3,
endorses IEEE Standard 387-1984.
This guide also describes a means for meeting the minimuia diesel generator reliability goals contained in R.G.
1.155.
In developing the guidance contained in R.G.
1.9, Rev.
3, for the diesel generator reliability program, the staff has taken cog-nizance of related industry initiatives and programs, and for the most part is consistent with current industry practices.
Both the staf f and the industry seem to be in agreeraent concerning R.G. 1.9, Rev.
3, except for those parts of Section C.6 and -accompanying figures and tables that prescribe in detail the requirements for a diesel generator reliability program.
NUMARC maintains that the licensees have committed to monitoring diesel generator reliability, and have docketed their commitments to maintain the chosen target reliability levels to comply with the Station Blae:kout Rule.
NUMARC considers that these commitments together with their initiatives are curricient to ensure acceptable diesel generator reliability.
Both the staff and NUMARC agree that diesel generator reliability has improved and the industry as a whole is maintaining reliability above the chosen... target levels.
NUMARC maintains that these efforts and results are adequate and that the prescriptive guidance contained in R.G.
1.9, Rev.
3, is unwarranted.
We believe that the commitments of the licensees to monitor and i
maintain diesel generator reliability above the chosen target levels and the industry initiatives are sufficient to ensure l
acceptable diesel generator reliability under the Station Blackout Rule.
If plants fall below the target levels, these plants should be identified and corrective actions will be taken.
We recommend that the prescriptive guidance contained in R.G.
1.9, Rev.
3, Sections C.6-2 through C. 6-7 be removed, along with the related figures and tables.
In addition, the staff should not issue a 50.54(f) letter to impose adoption of R.G.
1.9, Rev.
3.
Additional comments by ACRS Member Harold W.
Lewis are presented below.
Sincerely,
/Carlyle Michelcon chairnan
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The Honorable Kenneth M.
Carr 3
August 14, 1990
{
Additional Comments by ACRS Member Harold W.
Lewis I
First, I don't see the problem this program is supposed to solve.
Everyone seems to agree that diesel reliability is good and improving, and that each diesel failure should be analyzed for root cause, to reduce the likelihood of recurrence.
The remaining issue is the relevance of the threshold values.
- Clearly, failure experience is an indicator of the underlying reliability -- the question is how to use the data.
I am surprised that such a trivial measure as a collection of arbitrary threshold values has been chosen.
Once the failure data have been collected, it is no harder to make full use of the data, by calculating a set of confidence limits on the underlying reliability.
Such a procedure makes optimal use of the data, and can be recalculated after each attempt to start, with the expenditure of a few microseconds of computer time.
The trends and their significance can then be monitored.
I see no excuse for throwing away data, once collected.
Despite the staff assertions that this would be far more difficult, it would in fact be trivial.
i References.
1.
U.S. NRC Regulatory Guide 1.9, Rev. 3 (June 14, 1990), Working
- Draft,
" Selection,
- Design, Qualification,
- Testing, and l
Reliability of Emergency Diesel Generator Units Used As Class 1E Onsite Electric Power Systems At Nuclear Power Plants."
2.
U.S.
NRC Regulatory Guide 1.9, Rev.
2 (December 1979),
" Selection, Design, Qualification of Diesel-Generator Used as Standby (On-Site) Electric _ Power Systems at Nuclear Power Plants."
3.
Nuclear Management and Resources Council, NUMARC 87-00, (Revision 1),
"Guidel).e s and Technical Bases for NUMARC Initiatives Addressing Station Blackout At Light Water l
Reactors," Appendix-D, "EDG Reliability Program, " May 2, 1990 4.
IEEE Standard 387-1984, "IEEE Standard Criteria for Diesel-Generator Units Applied as Standby Power Supplies for Nuclear l
Power Generating Stations," June 1984.
j 5.
U.S.
Nuclear Regulatory Commission, Regulatory Guide 1.155 (Task SI 501-4), " Station Blackout," August 1988.
6.
U.S. Nuclear Regulatory Commission, Regulatory Guide 1.108, Rev.
1,
" Periodic Testing of Diesel Generators Used As On-Site Electric Power Sysens At Nuclear Power Plants," August 1977.
7.
Generic Letter 64-15, " Proposed Staff Actions to Improve and l
Maintain Diesel Generator Reliability," July 2, 1984.
i i
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