ML20116G877
| ML20116G877 | |
| Person / Time | |
|---|---|
| Site: | Clinton  |
| Issue date: | 10/29/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20116G869 | List: |
| References | |
| NUDOCS 9211120159 | |
| Download: ML20116G877 (9) | |
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p eg'o UNITED STATES
. E' 1 NUCLEAR REGULATORY COMMISSION g t W AM NGTON, D. C. 205%
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EVPPLEMENTAL SAFETY EVALUATION BY THE OfflCE OF NUCLEAR REAC10R REGULATION ELLATED TO THf STATION BLACK 0UT RULE (10 CFR 5.0.63) 1111N0ls p0WljL[@PANY. El At u LLIN10N POWER STATION, VNIT NO. 1 _
POCKET NO. 50-461 1.0 1HIRORUCT10N The NRC staff's Safety Evaluation (SE) pertaining to the Illinois Power Company's (the licensee's) response to the Station Blackout (SBO) Rule, 10 CFR 50.63, was transmitted to the licensee by letter dated May 29, 1992. The staff's SE found the licensee's proposed method of coping with an SB0 to be acceptable contingent upon the resolution of several recommendations itemized in the SE. The licensee responded to the staff's SE by letter dated July fi,1992.
2.0 EVALVATig The licensee's responses to the staff's concerns are evaluated below.
2.1 Londensate_Lnventory for Decay Heat Removal (SE Section 2.3.11 SE Recommendation In the SE, the staff recommended that the licensee should implement measures to ensure that the suppression pool temperature will remain below its limit. In addition, the licensee should verify that if the reactor core isolation cooling (RCIC) storage tank water was used, the suppression pool water level would not exceed the maximum allowable level.
Licenste_Renonse lhe licensee indicated that a new heat-up calculation is being performed and will be completed by Seotember 30, 1992, to demonstrate that the post-SB0 suppression pool temperature will be below its limit of 175'F as established in the emergency operating procedures. Mith respect to the maximum allowable suppression pool level limit, the licensee indicated that the level to which the suppression pool would be raised by adding the entire volume of the RCIC storage tank is lower than the level to which dumping the upper containment pools would raise the suppression pool, and that condition had been analyzed in the preparation of the plant Emergency Operatir.g Procedures (E0Pr)-
9211120159 921029 PDR ADOCK 0S000461 P PDR
o Staff Evaluation The staff finds the licensee's responses acceptable. Based on its review and subject to the audit of the-suppression pool heat-up calculation, the staff considers these SE issues resolved as they relate to the condensate invents for decay heat removal during an SB0 event at the Clinton plant.-
2.2 Class lE Battery Capacity (SE Section 2.3.2) 2.2.1 Last Minute loadina ,
SE Recommandation _
The licensee should ensure that the last-minute loading includes the same equipment that will be running before the last minute in addition to the equipment necessary to recover from the SB0 event.
Licensee Respanig The licensee stated that the last-minute battery-calculations include the loads -
for flashing the CDG field and operating the breakers and all other loads except the RCIC gland seal air compressor which will be shed at the 4-hour mark in accordance with Clinton Power Station (CPS) Procedure 4200.01.
51aff Evaluation The staff finds that the licensee has adequately responded to staff concerns regarding the last-minute loading of the battery.
2.2.2 RCIC_ Loads SE Recommendation The licensee should include RCIC loads in battery sizing calculations.
Licensee Response lhe licensee stated that there are two primary loads during RCIC operation: the.
gland seal air compressor and motor-operated valve operation. Both of these loads are included in the battery calculations. The gland seal . air compressor load _is assumed _from initietion of the SB0 event until the time of recovery.
Valve operation is included during the first minute of the event to establish valve lineup. For avied conservatism, the calculation includes operations of an
'RCIC motor-operated valve every 30 minutes throughout the 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> of the event..
Staff Evaluation The staff finds that the licensee has adequately responded to staff concerns regarding RClc operation.
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2.2.3 linhting El Recommendation The licensee should provide information as to how the lighting will be provided to perform the needed actions, i
Littnige Response The licensee stated that CPS has battery pack lighting with a built-in battery and built-in charger. The battery pack lighting comes on when the divisional power source is lost, as would be the case during an SBO. As part of the CPS 10 CFR Part 50, Appendix R review, CPS determined that sufficient lighting is available for up to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> after power is lost.
11aff Evaluation i The staff finds that the licensee has adequately responded to staff concerns i regarding lighting during an S80.
2.2.4 Other Staff Conrarm in the SE, the staff expressed concerns with respect to the first minute loading of the battery, the battery design margin, the inverter load, and monitoring of drywell, containment and suppression pool temperatures. The following was recommended.
SE Retommendation The licensee should verify that the Division 1 battery has sufficient capacity-taking into consideration the staff concerns as identified in Section t.3.2. .;
licensee Response With respect to the-first minute battery loading, the licensee noted that if all ,
loads that existed during the first minute were summed, the total load aould be !
on the order of 720 amps. However, CPS's analysis shows that the loads are not energized concurrently and justifies a maximum concurrent load during the first minute of 564 amps In accordance with the applicable standard, this load was then applied for the full first minute.
With respect to the. battery design margin, the licensee justifies its-use of'a design margin of 1,0 based on the fact that the design-margin of 1.1.to 1.15 stated in IEEE Standard 485 is used for selecting a battery and not to determine the adequacy of an existing battery. When the plant was designed and built, the IEEE design margin was used, but as loads were added, the design margin was reduced. During the third refueling outage in 1992, CPS replaced the. Division'I battery with a larger capacity battery, and there are plans to similarlyf replace -
the Division 11 battery in refueling outage 5 or 6 which will then restore its original design margin.
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With respect to the inverter loads, the licensee stated that t e loads on the inverter dur 19 an 500 are the same loads that the inverter su,,as during normal operation. The inverter current used in the calculation is what the inverter would draw with its input terminal voltage at 105 V.
With respect to monitoring the drywell, containment, and suppression pool temperatures, the licensee stated that it is revising procedure CPS 4200.01 to include instructions for connecting and using poriable test equipment. It is expected that this task will be completed by Septt.mber 30, 1992, t itALLinluat ion The staff finds that the licensee has adequately responded to staff concerns regarding the first minute loading of the battery, the inverter load, and the monitoring of drywell, containment, and supptession pool temperatures.
With respect to battery design margin, the staff accepts that the margin need ,
not be retained at the full 10 to 15% stated in IEEE Standard 485. However, a margin of at least 5% should be retained to provide for less than optimum operating conditions. In a telephone conversation on September 8, 1992, the licensee indicated that the current Division 1, 11 and !!! battery margins are all currently greater than 5%. Additionally, the licensee has indicated that the Division 11 battery, which has not been replaced or modified since original installation, is currently being evaluated for replacement or modification to increase its capacity. Based on this conversation, the staff finds the licensee's response currently acceptable. Ilowever, the licensee should respond, in writing, to the staff regarding its intentions to maintain a minimum 5%
design margin throughout the design life of their station batteries.
2.3 [f fpits ;of _l oss of Ventilation (SE Sectfon 2.3.4) 2.3.1 RCIC Rgam_and Steam Tynnel kl.AIPE1Dhl.1911 The licensee should verify that the RCIC turbine steam supply valve will be able to close should containment isolation become necessary during an 580 event. - The licensee should include all analyses and related information in supporting documentation that is to be maintained by the licensee-for staff review.
UIgnsee Resjtgna lhe licensee indicated that the AC-powered RCIC outboard containment isolation valve which is located in the main steam tunnel is normally open and will fail
as-is during an 500 event. Leaving this valve open will allow the RCIC-to rnmain operable during an SB0 event, llowever, DC-powered motor-operated valves which are downstream of this valve and accessible in the RCIC room can be used to isolate the RCIC turbine steam supply line, if necessary.
i 5-Staff Evaluation i Based on its review, the staff finds the licensee's response acceptable and, therefore, considers this SE issue resolved as it relates to the effects of loss of ventilation in the main steam tunnel duri.y an SB0 event at the Clinton plant.
2.3.2 Inverter Room SE Recom,nendations For the temperature of 80*f used as the initial temperature in the heat-up calculation to be acceptable, the licensee should have or establish an administrative procedure to ensure that this temperature would not be exceeded during normal power operation or use the maximum allowable temperature for these rooms. Second for the heat load in the room because of the inverters, the licensee should verify that it has used an inverter efficiency loss consistent with the expected inverter load, or use a constant efficiency loss based on the rated capacity of the inverter. The licensee should include all analyses and related information in supporting document tion that is to be maintained by the licensee for possible staff review.
Licensee Resnonse The licensee indicated that the heat-up calculations for the inverter rooms are being revised. More realistic inverter heat loads and initial-room temperature will be used in the revised calculation. The licensee further indicated that this revised calculation is expected to be completed by September 30, 1992.
Staff Evaluation The staff finds the licensee's response acceptable. Based on its review and subject to the audit of the heat up calculation, the staff-considers ti.ese SE issues resolved as they relate to the effects of loss of ventilation in the inverter rooms during an SB0 event at the Clinton plant.
It should be noted that, subsequent to issuing the SE, the staff has clarified its position with respect to the assumed initial temperatures used in the heat-up evaluations during an SB0 event. The staff position is that the licensee should document the basis and justification for.the assumed initial temperatures used in heat-up analyses for the control room and identified dominant areas of concern. The basis and justification should be included in the documentation that is to be maintained by the licensee in support of the SB0 submittals. If -
non-conservative initial temperatures are assumed (in this case, 80'f is non-conservative), then administrative procedures or other controls should be; established to maintain temperatures consistent with the initial temperatures used in the_ heat-up analyses, However,-if conservative initial temperatures _are used, then administrative procedures or other controls for the initial temperatures are not necessary but can be established.
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o 2.3.3 Control Room SE Recommendation The licensee should re-perform its control room heat-up analysis, taking into account the non-conservatism as identified in the SAIC TER (SAIC-91/6666, transmitted to the licensee on May 29, 1992) and verify the prior conclusion that the control room temperature would not exceed 120'F. The licensee should include all analyses and related inf ormation in supporting documentation that is to be maintained by the licensee for possible staff review. ,
licensee Reiponse The licensee provided detailed justification for the input parameters (e.g.,
outdoor temperature, initial room temperature, occupant heat load, etc.) used in-the control room heat-up calculation which indicated that, with the addition of a gasoline-powered exhaust fan, the control room temperature will be prevented from exceeding 120*F during an SB0 event (as reported in the SE, the staff found
-acceptable this licensee's approach to prevent the control room temperature from exceeding 120*f).
Staff Evaluation Based on its review and with the exception of the initial temperature of 73'f, -
the staff finds acceptable the licensee's justification for the input parameters used in the heat-up calculation acceptable. With respect to the initial temperature used in the calculation, the staff position as stated in the above Section 2,3.2 is that the licensee should document the basis and justification for the assumed initial temperature used in heat-up analysis for the control room. The basis and justification should be included in the documentation that u is to be maintained by the licensee in support of the SB0 submittals. If a non-conservative-initial temperature is assumed (in this case, 73*F is-non-conservative), then administrative procedures or other controls-should-be established to maintain the temperature consistent with the initial temperature used in the heat-uq analysis. However, if a conservative initial temperature is used, then administrative procedures or other controls for the initial temperature are not necessary but can be established.
24 Containment Isolation (SE-Section 2.3.5)
SE Recommendatica The licensee should establish an appropriate procedure to list the_ containment isolation valves (CIVs) which are either normally closed-or open and fail as-is upon loss of at power and cannot-be-excluded by the criteria-given in Regulatu y Guide (RG) 1.155, and identify the actions nece:sary to ensure-that these valves are fully closed, if needed. The valve closure should be confirmed by position indication. The licensee should include all analyses and related information in supporting documentation-that is to be maintained by the licensee. for possible staff review.
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Licfnsee Pesponse The ~ licensee indicated that a list of valves that may need -to be operated, and a list of valves;that would require manual operation if containment _ isolation is -
needed during an 590 event, have been added to the plant procedure 4200.01.
These valves have local stem position indication. Portable I.and-held lighting is available and would be used to provide lighting for confirming valve position during an 500 event. The licensee f ~ther indicated that it did not exclude any valves from consideration that are not allowed to be excluded by RG 1.155.
Staff Evaluation Based on its review, the staff finds the licensee's response acceptable and, therefore, considers this SE issue resolved.
2.5 Econosgsi Mod _ifications LSLSection 2.5)
LE Recommendation The licensee should reevaluate.the adequacy of the proposed fan after taking into consideration the staff cancerns discussed in Section .3.4 pertaining to the effects of lass of HVAC ir, the control room. The licensee should include a full description of the fan installation and how it meets the guidelines of Appendix B of NUMARC 87-00 in the documentation that is to be maintained by the licensee in support of the 580 submittals, licensee Respongg The licensee .tated that since CPS has presented adequate and acceptable-justification for the control room heat-up analysis, the basis for the concertual des'gn is sound, This modification, as part of the design process, will be subjected to a design review to confirm its adequacy. It-is expected that the modification will be-designed by June 30, 1993, and installed by May 29, 1994.
Staff Evaluation The staff finds the licensee's commitment to be acceptable ' subject to the use of--
a conservative initial temperature for the control room heat-up analysis, or the implementation of an administrative control of the control' room temperature as discussed in Section 2.3.3 above.
26 Ouality Assurance (OA) and Technical Soecification (TS) (SE Section 2,6)
SE-Recommendation The licensee should verify that the SB0 equipment is covered by an appropriate QA program consistent with the guidance of PG 1.155. Confirmation'that such a program exists should be documented as part of the package supporting the SB0 Rule response.
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8-Licensee Response The licensee stated that it is currently performing an analysis to determine if' the number of safety relief ve.lve (SRV) actuations _needed _for a 4-hour SB0 will require the use of the nonsafety-related backup compressed air bottles.
Preliminary results indicate that the backup air bottles will not need to be-included in the QA program to comply with the RG 1.155 requirements. It is -
expected that the evaluation will be et pleted by September 30, 1992.
Staff Evaluation The staff accepts the licensee's comn..t.nent to determine if the backup air bottles will not need to be included in the QA program to comply with the RG 1.155 requirements.
2.7 EDG Reliability Program (SE Section 2.7)
SE Recommendation The licensee should implement an EDG reliability program which meets the guidance of RG 1.155, Section 1.2. If an EDG reliability program currently exists, the program should be evaluated and adjusted in accordance with RG 1.155. Confirmation that such a program is in place or will be implemented should be included in the documentation supporting the SB0 submittals that is to -
be maintained by the licensee for possible staff review.
Li_censee Respons_e The licensee stated that at the time CPS submitted responses to the SB0 Rule each EDG had only approximately 25 starts. The combined EDGs have experienced no failures in the last 20 or last 50 starts and only one failure in the last 100 starts. The current data compares very well with the trigger values in NUMARC initiative SA.
The licensee also stated that CPS's EDG reliability program has incorporated the.
guidance in Appendix D of NUMARC 87-00.
1.taff Evaluation The staff accepts the licensee's chosen EDG target reliability of 0.95 based on
-the'NUMARC guidance.
However, with respect to the reliability program, the licensee apparently.is referencing Revision 1 of NUMARC 87-00 which has not been reviewed by the staff.
The version that has been accepted by the staff is NUMARC 87-00, November 20, 1987. The licensee, by telephone conversation on August 31, 1992, committed to ensuring that. the' EDG reliability program would follow the guidance of.
Regulatory Guide 1.155, Section 1.2.' The. staff accepts the licensee's commitment to comply with the RG 1.155 requirements. The staff finds the above licensee's response acceptable and, therefore, considers this SE issue resolved.
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SUMMARY
AND CONCLUSION ,
The licensee responded to the staff's May 29, 1992, SE. pertaining to the SB0 Rule (10 CFR 50.63) by letter dated July 6, 1992. The staff-has reviewed the '
licensee's response and finds it to be acceptable except with respect to the '
battery capacity margin (Section 2.2.4), the initial room temperature used in the control room heat-up calculation (Section 2.3.3), and the EDG reliability program (Section 2.7). Also, the licensee has committed to additional evaluations (Sections 2.1, 2.3.2, 2.6) that are expected to be- completed by September 30, 1992, and a design modification (Section 2.5) to be completed by May 29, 1994.
This SSE document- the NRC's final regulatory assessment of the licensee's ,
proposed conformance to the SB0 Rule. Therefore, no further submittals are required. The staff considers the 2-year clock for implementation of the SB0 Rule in accordance with 10 CFR 50.63 (c)(4) to begin upon receipt by the licensee of this SSE. Therefore, the licensee should take the necessary action -
to complete compliance with the SB0 Rule as indicated in the staff's SE and SSE.
The documentation of the analyses and actions required to resolve the itemized' concerns should be included with the other documentation to be maintained by the licensee in support of the SB0 Rule implementation for possible future MRC audit.
Principal Contributor: A. Toalston Date: October 29, 1992 km. 4 m -