ML20044B419
| ML20044B419 | |
| Person / Time | |
|---|---|
| Issue date: | 11/08/1990 |
| From: | Taylor J NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| To: | Remick NRC COMMISSION (OCM) |
| Shared Package | |
| ML20042D089 | List:
|
| References | |
| FRN-57FR14514, REF-GTECI-B-56, REF-GTECI-EL, RULE-PR-50, TASK-B-56, TASK-OR AE06-1-069, AE6-1-69, NUDOCS 9011270101 | |
| Download: ML20044B419 (11) | |
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UNITED STATES C L.V. - oo./ i
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NOV 0 81990 M, CA~t, ( f eO MEMORANDUM FOR:
Comissioner Remick
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James M. Taylor 8Bla -(
Executive Director for Operations
SUBJECT:
RESOLUTION OF GENERIC SAFETY ISSUE B-56, " DIESEL GENERATOR RELIABILITY" - REFERENCE SECY-90-340 I am responding to your memorandum to the Office of the Secretary of October 29, i
1990.
I would like to address the principal points in your memorandum and to provide an additional perspective on the reasons that the staff believes a generic letter and associated regulatory guide is necessary for the resolution of B-56.
The staff believes that the generic letter endorsing Regulatory Guide 1.9, Revision 3, is needed for four fundamental reasons:
l 1.
Licensees have established reliability targets of 0.95 or 0.975
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for emergency diesel generators (EDG) as part of their responses to i
the station blackout (SBO) rule.
However, although the selection of
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maintained, the SB0 submittals (y that selected levels will be a reliability target should impl with some exceptions) did not expressly make such a comitment, nor did the submittals identify the methods with which the licensees would monitor and maintain the performance of the EDGs. Further, a comon understanding throughout the industry of how these target reliability values are to be determined and assessed is important. The regulatory guide contains the necessary details, developed in conjunction with NUMARC, on the proper interpretation of operational and test results. The regulatory guide thereby assures that there is a known agreed-upon process for measuring EDG reliability.
2.
In SECY-90-340, the staff recognized that EDG reliability is generally very good across the industry. However, EDG reliability is not constant over time; each year a small number of plants (i.e., 3-5) fall below a target reliability value of 0.95. The plants falling below the threshold values are usually different each year. Thus, the staff needs to have confidence that when any plant falls below target values for reliability, this condition is detected (see item 1 above) and corrected. The regulatory guide establishes the nature and extent of corrective actions that are to be taken should the diesel reliability degrade. The staff developed this guidance jointly with NUMARC. The approach of using a regulatory guide to define an acceptable method of implementation of the rule is consistent with the approach envisioned during the issuance of the station blackout rule.
Contact:
F. Rosa, SELB/ DST X20774 e
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5 Comissioner Remick 3.
The above provisions are contained in NUMARC guidelines, but these guidelines do not constitute a licensee comitment.
In addition, the licensees did not include comitments in the docketed responses to the SB0 rule that they will implement these provisions. As.a result, licensees are free to adopt, revise, or implement these pro-visions as needed at any time. The staff is requesting a docketed comitment from each licensee to assure that licensees properly assess and maintain reliability values that are consistent with the j
I comitted target values, and.that all licensees and the public understand these specific provisions.
As discussed in SECY-90-340, the regulatory guide endorses the NUMARC guidance, and the staff recomends that the NRC issue a Section 50.54f generic letter to obtain the written comitment.
The staff has developed this approach-to minimize the staff's involvement and to place the responsibility for monitoring and maintaining diesel reliability directly on the licensee.
For example, to avoid disturbing or altering continuing licensee programs that have proven effective in assuring the reliability i
of diesel generators, detailed program guidance has been removed i
from the regulatory position and is only' contained in an appendix as an illustrative example of good industrial practices.
4 In regard to your question of the incompleteness of the SB0 rule, we believe that the rule is complete. However, more explicit language would have helped to clarify and thereby assure conformance with the SB0 analysis assumptions (e.g., EDG reliability) throughout the operating life of the plant.
However, this requirement is implicit in the rule and reinforced in the supporting guidance (Regulatory Guide 1.155, Position 1.2, and NUMARC 87-00, Section 3.2.4, and Appendix D).
i By requesting a licensee constitment to maintain EDG reliability, the proposed generic letter further clarifies this matter.-
With regard to the implications in the generic letter that the staff's position represented " requirements," the staff has clarified the letter to remove this implication.
I have enclosed a copy of the revised (proposed) generic letter-for your information. This revision should be considered in place of Enclosure 5 to SECY-90-340.
In addition, I want to clarify that enforcement is not the objective of this or other NRC generic letters. Enforcement is an "after-the-fact" detemination and is used only when agreed-upon actions have not been implemented. Enforcement is not used to establish the nature of actions that should be taken.
Finally, the staff has always envisioned a diesel generator reliability program as part of the implementation of the SB0 rule.
Further, treating a diesel
l Comissioner Remick
-3 generator reliability program through a licensee comitment rather than a rule allows much more flexibility in implementation.
It allows licensees to implement a program of their making while providing sufficient assurances to satisfy the staff that the concern is being addressed. By issuing the generic letter, the staff will gain an adequate basis for confidence that a reasonable and effective diesel reliability program is in place, and will remain in place.
The staff would be pleased to provide any additional information you may wish, and is available should individual oral discussions be helpful.
I C. :;,:. Sigatd CA
25!!s,Ia'ICT.
j James M. Taylor Executive Director for Operations
Enclosure:
As stated cc: Chairman Carr Comissioner Rogers l
Commissioner Curtiss SECY l
OGC Distribution:
Central Files EBeckjord SELB Rdg.
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[F Rosa ED0 5953 C. Heltemes W. Russell F. Miraglia T. Hurley J. Taylor J. Sniezek E. Beckjord J. Partlow E. Jordan H. Thompson J. Blaha EE PREVIOUS CONCURRENCE d
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ENCLOSURE l
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10/18/90 DRAFT 1
l PROPOSED GENERIC LETTER (REFERENCE GSI B-56) l l
I TO:
ALL HOLDERS OF OPERATING LICENSES OR CONSTRUCTION PERMITS FOR NUCLEAR POWER REACTORS.
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SUBJECT:
RESOLUTION OF GENERIC SAFETY ISSUE (G8I) B-56, l
" DIESEL GENERATOR RELIABILITY" (GENERIC LETTER 90-
)
1 PURPOSE AND BACKGROUND:
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This generic letter is being sent to all licensees of operating d
nuclear power reactors and to all construction permit holders to l
determine whether licensees will voluntarily implement NUMARC's 1
Initiative SA, " Coping Assessment /EDG Performance,"W (see j
Enclosure A) and the guidance for monitoring and maintaining
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Emergency Diesel Generator (EDG) reliability as described in 1
Regulatory Positions C.3, C.4, C.5 and C.6 of Regulatory
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Guide 1.9, Revision 3.
i The Staff has issued Revision 3 of Regulatory Guide 1.9,
" Selection, Design, Qualification, Testing and Reliability of i
Diesel Generator Units Used as Class 1E Onsite Electric Power Systems at Nuclear Power Plants" which presents the staff's j
l guidance for the technical resolution of GSI B-56.
This revision l
integrates into a single document guidance on EDG selection, j
design, qualification and testing previously addressed (or
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provided) in Revision 2 of Regulatory Guide 1.108, Revision 2 of Regulatory Guide 1.9, and Generic Letter 84-15. Reporting of EDG j
failures in conformance with 10 CFR Parts 50.72 and 5d.73 will continue. Licensees are also encouraged to continue to report EDG failures to NPRDS.
i 10 CFR 50.63, " Loss of All Alternating Current Power", requires that all LWR nuclear power plants be able to withstand and 4
j recover from a station blackout.
The reliability of EDGs used as onsite emergency AC power sources is one of four primary i
3 considerations listed in-Section 50.63 for assessing the ability.
of the plant to withstand station blackout.
The Staff provided initial guidance for monitoring and maintaining EDG reliability j
for compliance with Section 50.63 in Regulatory Position 1.2 of Regulatory Guide 1.155, " Station Blackout" which recommends that 1
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reliable operation of onsite emergency AC power sources should be j
ensured by a reliability program designed to maintain: and monitor
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the reliability of each power source.over time for assurance that selected reliability levels are being achieved.
It was noted in the Federal Register Notice (53 FRN 23218) that: "The resolution of B-56 will provide specific guidance for use by the staff or l
industry to review the adequacy of diesel generator reliability programs consistent with the resolution of USI A-44."
RG 1.9, 1
Rev. 3 provides such specific guidance.
1 4
INFORMATION REOUIRED TO BE SUBMIITED_)I_ADDEE181Ef_t.
In order to determine whether any operating license or i
construction permit for facilities covered by this request should be modified, suspended, or revoked, you are required, pursuant to Section 182 of the Atomic Energy Act and 10 CFR 50.54(f), to submit information-to the NRC, under oath or affirmation, within 180 days of the date of receipt of this letter, regarding your current plans for assuring adequate diesel generator reliability.
I For your guidance the staff has identified an approach for i
resolving GSI B-56 which, if implemented, would provide an l
acceptable method for monitoring and maintaining EDG reliability -
j levels as required for compliance with 10 CFR 50.63.
That
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approach consists of implementation of NUMARC's Initiative 5A and.
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j Regulatory Positions C.3, C.4, C.5 and C.6 of Regulatory Guide j
1.9, Revision 3.
The staff recognizes that equally effective programs for monitoring and maintaining EDG' reliability may have a
already been implemented by licensees.
In such instances, if a program has successfully demonstrated its effectiveness in j
i achieving and maintaining the target levels of diesel generator reliability, such a program, would be considered by the staff to be an acceptable equally effective program.
In such instances, no changes to an existing approach would be considered necessary.
l In your required response to this letter, addressees are roguested to indicate their commitment to implement either the suggested acceptable program consisting.of NUMARC's Initiative 5A I
and Regulatory Positions C.3, C.4, C.5 and C.6 of Revision 3 to i
Regulatory Guide 1.9 (or equivalent MUMARC. guidance as indicated j
in Table 1 of Regulatory Guide 1.9, Revision 3), or an equally affective program for monitoring and maintaining EDG reliability levels for compliance.with 10 CFR 50.63.
If you plan to implement an approach other than the suggested acceptable j
approach, your response should describe your program, including justification that it represents an equally effective approach.
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Your response should also provide a commitment to implement your program at the earliest possible date, but in no case later than j
270 days from the date of receipt of this letter.
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You should retain all documentation supporting this responsa consistent with the records retention program for your facility.
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i Licensees that implement NUMARC Initiative 5A, and Regulatory 1
j Positions C.3, C.4, C.5, and C.6 of Revision 3 of Regulatory Guide 1.9 (or equivalent NUMARC guidance as indicated in Table 1 of this regulatory guide) may include a request to change their j
plant Technical Specifications (TS) to incorporate the line-item 1
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improvements noted in Enclosure B.
These line-item TS j
improvements are a result of the implementation of programmatic j
requirements for monitoring and maintaining EDG target 4
reliability.
Guidance for the preparation of a proposed license j
amendment to implement these line-item TS improvements is i
provided in Enclosure C.2.
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BACKFIT DISCUSSION b
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The regulatory analysis for UsI A-44 is contained in NUREG-1109, j
" Regulatory /Backfit Analysis for the Resolution of Unresolved i
Safety Issue A-44, Station Blackout", June 1988.
This regulatory f
analysis evaluated costs associated with implementation of EDG 1
reliability programs and concluded that there will be a i
substantial increase in overall protection of public health and i
safety, and that the costs are justified in view of this I
increased protection.
The staff reaffirms that the regulatory
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analysis developed for USI A-44 is applicable to the resolution i
of GSI B-56 and therefore a new regulatory analysis will not be developed for GSI B-56.
I In Revision 3 of Regulatory Glide 1.9, the actions proposed by i
the NRC staff in Regulatory Pesitions C.3, C.4, C.5, and C.6 3
represent new staff positions and are considered a backfit in accordance with NRC procedures.
The staff believes that this approach, the implementation of Regulatory Positions C.3, C.4, C.5 and C.6 of Regulatory Guide 1.9 Revision 3, is the most cost effective method for maintaining emergency diesel generator reliability since the proposed actions are consistent with practices developed by the nuclear industry.
A backfit analysis of the type described in 10 CFR 50.109(a) (3) and 10 CFR 50.109(c) was performed based on the regulatory analysis of NUREG-1109.
This backfit analysis is included in the Federal Register Notice I
for the issuance of Revision 3 of Regulatory Guide 1.9, and will I
be made available in the Public Document Room along with the l
minutes of the 171st, 176th and 190th meetings of the Committee to Review Generic Requirements-that discussed the resolution of this generic issue.
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i PAPERWORK REDUCTION ACT REOUIREMENTS This request is covered by Office of Management and Budget clearance Number 3150-0011, which expires The i
estimated average burden hours is 120 person-hours per license response, including assessing the new recommendations, searching data sources, gathering and analysing data, and the required reports.
These estimated average burden hours pertain only to these identified response-related matters and do not include the time for actual implementation of requested actions.
Estimates of implementation of an EDG reliability program.are reported in NUREG-1109, " Regulatory /Backfit Analysis for the Resolution of Unresolved safety Issue A-44, station Blackout."
Comments on the accuracy of this estimate and suggestions to reduce the burden may be directed to the U.S. Office of Management and Budget, Executive Office Building, Washington, D.C. 20503, and to the' Nuclear Regulatory Commission, Records and Reports Management Branch, Office of Administration and Resources Management, Washington, D.C.
20555.
If you have any questions on this matter, please contact your project manager.
Sincerely, James G. Partlow, Associate Director for Projects Office of Nuclear Regulation l
Enclosures:
1.
Enclosure A, NUMARC Initiative SA 2.
Enclosure B, Guidance for the Preparation of License Amendments 3.
List of Recently Issued Generic letters
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Enclosure A NUMARC INITIATIVE 5A j
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" COPING ASSESSMENT /EDG PERFORMANCE" 3
(Ref. NUMARC 87-00, Rev.
1, May 2,1990) i The following verbatim quote of NUMARC's Initiative 5A is provided for convenience :
"Each Utility will assess the ability of its plant (s) to cope with a " Station Blackout."
Plants utilizing i
alternate AC power for " Station Blackout" response
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which can be shown by test to be available to power i
the shutdown busses within 10 minutes of the onset of
" Station Blackout" do not need to perform any coping j
Remaining alternate AC plants will assess assessment.
i their ability to cope for one-hour.
Plants not utilising an alternate AC source will assess their 3
j ability to cope for four hours.
Factors identified j
which prevent demonstrating the capability to cope for the appropriate duration will be addressed through l
hardware and/or procedural changes so that successful 1
1 demonstration is possible.
As part of the coping assessment, utilities are 4
j required to choose an EDG target reliability (0.95 or i
0.975) and are required to maintain that chosen i
reliability.
Accordingly, each utility will employ the
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fo11cwing exceedence trigger values (on a plant unit J
basis) as the mechanism for monitoring EDG Target i
Reliability and support closure of Generic Issue B-56:
SELECTED i
EDG TARGET FAILURES IN FAILURES IN FAILURES IN j
RELIABILITY 20 DEMANDS 50 DEMANDS 100 DEMANDS 0.95 3
5 8
f 0.975 3
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j Additionally, each utility, in response to an i
individual EDG experiencing 4 or more failures
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in the last 25 demands, will demonstrate restored EDG l
' performance by conducting seven (7) consecutive failure j
free start and load-run tests.
This reduced fera of accelerated testing shall be conducted-at a frequency of no less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and of no more than seven - (7) s days between each demand.
Each utility will,'if applicable, address this reduction in accelerated testing through changes to technical specifications or a
l other appropriate means."
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i Enclosure B GUIDANCE FOR THE PREPARATION OF A LICENSE AMENDMENT REQUEST TO MODIFY EMERGENCY DIESEL GENERATOR SURVEILLLNCE, ACTION, AND REPORTING REQUIREMENTS BACKGROUND A program for monitoring and maintaining the reliability of i
amargency diesel generators (EDGs) is an essential element for assuring that the selected EDG target reliability for compliance (10 CFR 50.63) is set.
The with the station blackout rule establishment of this program-in accordance with the guidance in Regulatory Positions C.3, C.4, C.5 and C.6 of Revision 3 to Regulatory Guide 1.9 will permit a reduction in the accelerated frequency of EDG monthly surveillance requirements that are applicable to most operating plants. For the remaining plants, the implementation of an acceleratsd frequency for monthly EDG surveillance requirements, consistent with a commitment to NUMARC Initiative 5A, constitutes.a backfit.
Also, a relaxation in the reporting requirements for EDG failures, consistent with Regulatory Position C.5 of Revision 3 of Regulatory Guide 1.9 is appropriate.
Consistent with the NRC policy on Technical Specification (TS) improvements, this guidance is provided for a license amendment request to implement these line-item TS improvements.
~ ~~Dt9CCBSION current plant TS typically require an accelerated frequency of j
once per 7 days for conducting EDG monthly surveillance l
requirements when the number of failures exceeds 1 in the last 20 or 5 in the last 100 valid tests on a per diesel generator basis.
l With the implementation of a EDG reliability program conforming i
the to the guidelines of Revision 3 to Regulatory _ Guide 1.9, staff has concluded that 4 or more failures in the last 25 valid tests is acceptable for imposing an accelerated test frequency for monthly surveillance requirements.
Furthermore, the accelerated testing may be suspended following 7 consecutive failure-free tests.. Details.for the new accelerated testing are included in the following revised T8 Table 4.8.1.1.2-1.
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An acceptable alternative to the existing requirements of x
TS Table 4.8.1.1.2-1 is the following:
Table 4.8.1.1.2-1 DIESEL GENERATOR TEST SCHEDULE NUMBER OF FAILURES IN TEST FREQUENCY LAST 25 VALID TESTS
- Once per 31 days
<3 Once per 7 days **
>4 (but no less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />)
Criteria for determining number of failures and valid demands shall be in accordance with Regulatory Position C.2.1 of Regulatory Guide 1.9, Revision 3, where the number of demands and failures is determined on a per diesel generator basis.
The criteria are based upon counting only those failures that have an impact on the capability of the EDG to respond to a station blackout.
However, the ACTION requirements must be met for those fast start failures that are excluded for determining the number of-failures in the last 25 valid tests.
This test frequency shall be maintained until 7 consecutive failure-free start and load-run demands have been performed.
If, subsequent to the 7 failure free tssts, 1 or more additional failures occur such that there are again 4 or more failures in the last 25 tests, the testing interval shall again be reduced as noted above and maintained until 7 consecutive failure-free tests have been performed.
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The changes to Table 4.8.1.1.2-1 are in the number of failures in I
the last 25 valid tests.
The
- footnote is changed to reflect the updated criteria on valid tests and failures provided in f
Regulatory Position C.2.1 cf Revision 3 to Regulatory Guide 1.9.
l The criteria are based upon counting only.those failures that
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have an impact on the capability of the EDG to respond to a l
station blackout.
Therefore, it is noted that the ACTION l
requirements must be met for those fast start-failures that are excluded for determining the number of failures in the last 25 i
valid tests.
The ** footnote is changed to reflect testing.
requirements noted in' Regulatory Position C.3.4 of Regulatory Guide 1.9 and Initiative 5A of NUMARC 87-00.
Individual plant TS may have other notes relating to reducing the previous failure count to zero following a complete diesel overhaul.- With the-l l
change in the requirements for initiating and terminating the accelerated frequency for monthly surveillance requirements, notes related to reducing the previous failure count to zero 2
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following a complete diesel overhaul are no longer appropriate and should be deleted.
The " Bases" section for TS 3/4.8.1 should be updated to note that the basis for this TS also includes this generic letter.
I Finally, with the implementation of recordkeeping requirements on EDG failures as a part of the above noted programmatic requirements for monitoring and maintaining EDG reliability, the staff has concluded that a special report for all EDG failures is no longer necessary.
Accordingly, the following provides an acceptable alternative for TS 4.s.1.1.3. This is consistent with Regulatory Position C.5 of Revision 3 to Regulatory Guide 1.9:
4.8.1.1.3 Reports - Reports en failures of the emergency diesel generators shall include the information noted in Regulatory Position C.5 of Regulatory Guide 1.9, Revision 3,
" Selection, Design, Qualification, Testing, and Reliability of Emergency Diesel Generator Units Used as Class 1E Onsite Electric Power Systems at Nuclear Power Plants," Revision 3, 1990.
SUMMARY
The above alternative to the present requirements of Table 4.8.1.1.2-1 will permit a reduction in the accelerated frequency of EDG monthly surveillance requirements.
Finally, a reduction in the reporting requirements for EDG failures is also appropriate with the implementation of recordkeeping requirements noted above.
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