ML19327B418
"Draft Meeting" is not in the list (Request, Draft Request, Supplement, Acceptance Review, Meeting, Withholding Request, Withholding Request Acceptance, RAI, Draft RAI, Draft Response to RAI, ...) of allowed values for the "Project stage" property.
| ML19327B418 | |
| Person / Time | |
|---|---|
| Issue date: | 10/24/1989 |
| From: | Tam P Office of Nuclear Reactor Regulation |
| To: | Marion A NUCLEAR ENERGY INSTITUTE (FORMERLY NUCLEAR MGMT & |
| References | |
| TAC-40577, NUDOCS 8910310141 | |
| Download: ML19327B418 (7) | |
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UNITED STATES e:
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NUCLEAR REGULATORY COMMISSION p,
WASHINGTON, D. C. 20665
!i ; %,*...a October 24, 1939 Mr. Alex Marion o'
NUMARC 1776 I Street, N.W.
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' Washington, DC 20006 f.:
Dear Mr. Marion:
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SUBJECT:
TRANSMITTAL OF DRAFT DOCUMENT TO BE USED FOR DISCUSSION IN THE OCTOBER 30, 1989 MEETING ON STATION BLACK 0UT (TAC 40577)
Enclosed please find a draft letter which will be used in the discussion of the October 30, 1989 meeting. The early release of this draft should ensure meaningful exchanges in the meeting.
Sincerely, 0
Peter S. Tam, Senior Project Manager Project Directorate I-4 Division of Reactor Projects I/II Enclosure : as stated i
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., Enclosure to letter, P. Tam to A. Marion, dated October 24, 1989.
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ALL HOLDERS OF. OPERA, EACTOR LICENSEES AND APPLICANTS I
SUBJECT:
STATION BLACK 0UT RESPONSE S ITTALS ANALYSES AND RESPONSES (GENERIC LETTER 89-XX) q H
i PURPOSE AND BACKGROUND:
The purpose of this generic letter is (1) to inform licensees of_ problems identified during staff review of licensee responses to the station black-out(SBO) rule (10CFR50.63),d[g'ehstadditionalinformationthatisre sql uring the site audit reviews of the sup-portingdocumentation;and(2[
r quired to enable the staff to more' accurately assess licensee conformance with the requirements of the SB0 rule.
Pursuant to 10CFR 50.63 (Station Blackout Rule), licensees were required to be able to withstand SB0 for a specified duration and to recover. Licensees were also required to provide a submittal which described their plants' compli-ance with the specific provisions of the rule, in addition, licensees were to have available for NRC review the baseli ssumptions, analyses and related information used in their coping evalua.
is supporting documentation was to allow the NRC to assess conforma'nc
~ rule by audit of the docu-l l
mentation supporting the SB0 submittal. Durin, eetings with NUMARC and the NRC it was agreed that the guidelines of NUMARC 87-00 as modified by Regulatory Guide 1.155 provided an appropriate basis for conducting analyses to determine j
compliance with 10CFR 50.63 and identify needed modifications. All licensees responses were submitted on schedule in accordance with 10CFR 50.63.
1 AUDIT FINDINGS:
l The staff conducted audit reviews of the documentation supporting the station
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' blackout (SBO) submittals for several plants. These audit reviews were performed at the sites and corporate offig and included plant walk-through to assess design features of major relevy thyplorting documentation for fou SB0 submittal.
In addition, the NRC conducted audit reviews of the SB0.%gp l
through meetings with licensees at the NRC headquarters. Several deficiencies in the licensee supporting documentation were identified during these audit reviews. The fact that these deficiencies were not apparent from the review 1
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E of.the licensee submittals using th d upon generic response format raises r
the question of the licensee confo he SB0 rule. The deficiencies that have been identified during the audit'r ws conducted so far are presented below.
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1.
Improper interpretation of guidance for determining required SB0 duration:
Two plants had used the Regulatory Guide 1.155 and NUMARC 87-00 guidance improperly in determining the required coping duration. The licensee of the two plants had incorrectly classified the offsite group as 12 instead of 13, and onsite emergency diesel generator group as A instead of C.
Based upon the incorrect offsite and onsite
, the licensee had wrongly classified
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the plants required coping durat1 hours when, in fact, it should have been eight hours.
2.
Disabling and evacuation of control room due to lack of battery capacity or for purposes of extending the battery capability:
One licensee had proposed the voluntary disabling and evacuation of the main control room for the purposes of extending the battery capability from 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. Another plant had proposed to transfer control of the plant shut-down from the control room after 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to the auxiliary shutdown panel because of lack of battery capacity to power the control room.
In neither of these cases had the licensee identified in his SB0 submittal that there was any intent to evacuate the control room. The circumstances under which these plants propose to evacuate the contrci room are known and the actions necessary to conserve battery energy and transfer contr a remote shutdown panel are nuserous with high potential for human error u tidpuress of SB0 situation.
It is the staff's position that evacuation of g/ control room is a last resort action and is not appropriate except for unforeseen circumstances which physically force evacuation. Operators are well trained and familiar with monitoring and control from the main control room and while some action outside the control room
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j 3-s is. permitted by the rule they should not required to leave their normal operating environment when other engine tions are viable for the known r,cenario of SBO.
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. Additionally,'it would be necessary to perform actions from the control room to recover from the SB0 and return to normal cold shutdown conditions.
It is not in the.best interest of safety to voluntarily disable and evacuate the control room for mitigating SB0 and recovery therefrom.
3.
Incomplete or improperly performed calculations for assessing effects of loss of ventilation:
A majority of the plants that were audited had either incomplete or improperly performed calculations for assessing the effects of loss of ventilation on the operability and reliability of equipmen,
ssary to cope with SBO. Plants i
that do not have an alternate ac power..[
ailable within 10 minutes) to power ventilation systems are required to #as s the effects of loss of ventila-tion accoroing to the methodology described in NUMARC 87-00. The NUMARC 87-00 l-methodology for assessing the effects of loss of ventilation are limited to a four hour SB0 duration. Plants with coping duration in excess of four hours are required to use a methodology acceptable to the NRC. The NRC audit review indicated that the licensees are not consistently adhering to the methodology as described in the NUMARC 87-00.
l 4.
Improper credit for hurricane procedures:
l According to NUMARC 87-00, a plant may reduce its required coping duration from l
8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> by implementing sp fic pre-hurricane shutdown requirements l'
and procedures. One plant selected ion of reducing its coping duration from 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, but chose n the shutdown requirements 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> prior to the arrival of the hurricane.
NRC expects the licensees to follow l
fully the NUMARC 87-00 guidelines for taking credit for enhanced coping capability l
under anticipated hurricane conditions.
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5.
Improper credit for Diesel Generators (EDGs) as alternate ac (AAC M
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'A licensee o units) proposed using existing emergency diesel generators (EDGs) as the AAC source.
However, a single cross-connect and switchgear is provided between units for the AAC power source which does not meet the guidance of R.G.
1.155 and NUMARC 87-00 (Section 2.3.1(3)(b) and Appendix C, page c4).
In addi-tion, the switchgear is located outdoors with interconnecting circuits run over-head which make it vulr.erable to a weather related event or a single failure in the non-bleckout unit.
6.
Inadequate coping analysis and/or modifications:
Several licensees had not followed the guidance of NUMARC 87-00 regarding the
. pump seal leakage rate in the reactor coolant system (RCS) inventory analysis.
One licensee had indicated in his.
Jt.tal that he had performed the RCS inventory analysis however, during',
ft it was found that no analysis had been performed. Another licensee had' dtifiedthatmodificationsweretobe N
made to the atmospheric dump valves but could not explain what these modifica-
.tions were. Some BWR licensees had indicated that they were going to use reac-tor core isolation cooling (RCIC) however, they had not analyzed t.he suppression I
pool heatup to determine RCIC operability and heat capacity temperature limit.
These examples are indications of deficient coping assessments as required by the R.G. 1.155 and NUMARC 87-00.
7.
Lack of verification of baseline assumptions for assessing equipment operability:
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During the site audit review, several icensees stated that the assessment of SB0 equipment operability in the c m and other areas was not required based on the NUMARC S7-00 assumpti equipment would be operable at a final temperature up to 120*F.
However.,section 1.3 of NUMARC 87-00 states:
" Utilities are expected to ensure that the baseline assumptions are applicable l
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s to their plants.".Therefore, an asse nt of operability for the SB0 equipment not designed to operate a t temperature calculated for the control room and other areas during an ent should have been made. The staff expects the licensees to verify the RC 87-00 assumptions for appli-cability to their plants.
8.
Lack of comitment to establish an EDG reliability program:
R.G.1.155, Section 1.2 and NUMARC 87-00, section 3.2.4 state that an EDG reli-ability program should be established to ensure that the reliability of EDGs is monitored and maintained over time at the selected target levels. The licensee SB0 responses have not addressed this comitment.
It is expected that each licensee will commit to establish a iability program in accordance with elements of R.G. 1.155 or NUMARC 8 endix D.
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Deficiencies in the SB0 supporting docume (tation identified during the audits -
4 include lack of completeness and tendency of the licensees to interpret or extend the guidance provided in R.G. 1.155 and NUMARC 87-00 in a manner to justify minimum design changes rather than improved piotection against SBO.
RECOMMENDED ACTIONS TO BE TAKLp BY ADDRESSEES AND REPORTING REQUIREMENTSi in order to determine whether any license or construction permit for facilities r
covered by this request should be raodified, tuspended or revoked, wt. require, pursuant to Section 182 of the Atomic Energy A(t and 10 CFR 50.54(f), that you i
provide the NRC, within 30 days of t letter, a statement as to whether you have conducted your t,tation blackou[
es in accordance with the guidelines of NUMARC 87-00 as modified by kegu' e 1.155, and whether the response you previously submitted accurately prese, the conclusions of your analyses and is supported by technically sufficient documentation.
in the event that licensees determine that previous submittals need revision, licensees should submit re-visions to previous conclusions with a statement that the submittal is in conformance with the above guidance and supported by technically sufficient
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documentation. This information should be submitted to the NRC, signed under oath and affirmation. The licensee should retain supporting documentation consistent with the records retention program for their facility.
This request is covered by Office nt and Budget Clearance Number 3150-0011, which expires he estimated average burden hours are 120 person-hours per license response, including assessment of the new recommendations, searching data sources, gathering and analyzing data, and
. the required reports.
T!< 4e estimated average burden hours pertain only to these identified response-related matters and do not include the time for actual implementation of requested actions. Coments on the accuracy of this estimate and suggestions to reduce the burden may be directed to the Office of Management and Budget, Room 3208, New Executive Office Building, Washington, D.C. 20503, and to the clear Regulatory Commission, Records and Reports Management Branch, O Administration and Resources Management, Washington, D.C. 2055 1
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