ML20024H008
| ML20024H008 | |
| Person / Time | |
|---|---|
| Site: | Zion File:ZionSolutions icon.png |
| Issue date: | 05/10/1991 |
| From: | Taylor D COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9105170257 | |
| Download: ML20024H008 (8) | |
Text
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Office of Nuclear Reactor _ Regulation U.S. Nuclear Regulatory Commission Attn: Document-Control Desk Hashington, DC.20555
Subject:
Zion Station Units 1 and 2 Pesponse to Station Blackout Rule safety Evaluation MC_Docke2.Jio,_50-295130L
References:
- '(a) 10 CFR Part 50.63, Loss of all Alternating Current Power.-
(b) M. Richter (CECO)-letter to U.S. NRC, dated Aprtl 17, 1989.
(c) M.-Richter-(CECO) letter to U.S. NRC, dated March 20,_1990.
(dL R. Chrzanowski (CECO) letter to U.S. NRC dated September 20, 1990.
(e)-C Patel letter to T.J. Kovach dated April 3,1991
-Reference (a)-requires that each light-water-cooled nuclear power plant be able to withstand and__ recover from a station blackout (SBO) of a specified duration,' A response:to the SB0 rule was required from each licensee by April 17, 1989.
Reference (b) provided Commonwealth Edison Company's (CECO) initial
-response to the SB0_. rule for_ Zion Station.
For this response, Zion Station-was evaluated against the requirements of the SB0 rule using guidance from NUMARC-87-00 and Regulatory Guide 1.155.
References (c) and (d) provided additional information related to SB0 for Zion Station.
Reference (e)
.provided the NRC Safety Evaluation of the_ Zion Station response to the SB0
-Rule.
'In response to reference d) and in accordance with 10 CFR 50.63(c)(4),
CECO herein provides the requested schedular information, as Attachment 1, related'to the Zion Nuclear Generating Station's conformance with the SB0 Rule.
._ Please direct any questions that yc3 may have related to this response to
- this office.
Sincerely,
[
~
1 Darrell Taylar Nuclear Licensing Administrator cc:: A^8. Davis - Regional Administrator, Region III L
C. Patel - Project Manager, NRR Resident Inspector _- Zion-Station
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9105170257 910510 d 0,fo ZNLD/902/3 PDR-ADOCK 05000295
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4 ATTACHMENT i
l SCHEDULE FOR IMPLEMENTATION In accordance with 10 CFR.50.63(c)(4), CECO provides the following schedule for inpleiner.tation of proposed hardware and procedure iaodifichtions, including those resulting from deficiencies documented in the Safety Evaluation.
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- All proposed procedure modifications not associated with hardware modifications including any resulting from the deficiencies documented in l
the Safety Evaluation will be implemented by April 3, 1992.
All proposed procedure modifications associated with hardware modificattor.>
1 and all hardware modifications including any resulting from the deficiencies documented in the Safety Evaluation will be completed by April 3, 1993.
The deficiencies noted in the Safety Evaluation are discussed further in the following pages.
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1 ZNLD/902/4
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i S af ety_ E v a l u a tiorLRepotL S e c t ion %2,22 Deficiency:
The licensee should commit to performing a test to demonstrate that the AAC power source can power the SB0 loads within ten minutes.
The licensee should confirm that one CCH pump powered from the Unit 1 NGO unit has sufficient capacity to provide the necessary cooling for both units under LOOP conditions without degrading the cooling capability of the NB0 unit.
RESPONSE
All Zion's dedicated diesel generators are automatically started and connected to their respective shutdown buses upon loss of offsite power.
The swing diesel (EDG 0) will automatically power a bus at either Unit 1 or Unit 2.
If both dedicated diesels for a unit fail and EDG 0 does not align with that unit automatically, it can be manually re-aligned from the control-room.
As. discussed in the SER dated April 3, 1991, Zion will conduct a test to demonstrate that power from the swing diesel can be transferred from a division at one unit to a division the other in less than ten minutes.
This test will be carried out in accordance with the guidance provided in NUMARC 87-00 Appendix B and Regulatory Guide 1.155. Documentation of this test will be included in the station's SB0 backup documentation.
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e SafflLEYahlltioILRepar_i__Settictrt2 L22 Deficiencyl The licensee should verify and confirm that adequate battery capacity will be assured for an S80 on either unit, a LOOP on the other unit, and failure of either EDG on the HBO unit.,
The documentation describing how the battery capacity adequacy would be maintained should be included with the other documentation supporting the licensee's response to the S80 rule.
RESPONSE
J CECO will include a description documenting the adequacy of Zion's DC power capabilities during a station blackout in the station's SB0 backup documentation.
This discussion will e;; plain how adequate battery capacity is available during an SB0 at either unit combined with a single failure of an EDG at the adjacent unit.
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l ZNLD/902/7
4 4-S afe tyly aluatiotLRe pott _Se c tion 1L S :
- Deffilencyr The-licensee should confirm that the pro)osed AAC source provides power to all appropriate isolation valves to assure containment isolation can be obtained during an SB0.
If the proposed AAC source does not provide power to all appropriate valves, then the licensee should provide assurance of containment isolation by listing those valves not powered by the AAC source in an appropriate procedure and by identifying actions iequired to ensure these valves are fully closed by providing position indication (local, remote, etc.)
independent of preferred and EAC power sources.
The supporting analysis and the documentation should be included with the other information to be maintained by the licensee in support of its SB0 submittals.
RESPONSE
CECO will include a description of how position indication and closure capability would be provided during station blackout conditions for all containment isolation valves of concern (as discussed in NUMARC 87-00 Section 7.2.5).
This description will be included with the station's SB0 backup documentation.
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- SafetylnluatloalenoriSettion_2151 Refittency:
The licensee should include a full description of the proposed modifications and document this information in the documentation to be maintained by the licensee supporting the 580 submittal.
RESPONSE
A full description of station blackout related plant modifications will be included with the station's SB0 backup documentation.
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0 ZNLD/902/5
4 S ate tL Evalu at kttle porLS e c tiorL2,61.
Deficiency:
The licensee should verify that the SB0 equipment is covered by an appropriate QA program consistent with the guidance of RG 1.155.
- Further, this verification should be documented as part of the package supporting the SB0 rule response.
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- RESPONSE:
CECO will develop a list of all equipment required to respond to a station blackout noting their QA disposition. Any components that are not already.
covered by 10 CFR 50 Appendix B or R, will be incorporated into a QA program that meets the guidance of Regulatory Guide 1.155.
This equipment list will be included with the station's 500 backup documentation.
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ZNLD/902/9
4 Safe _ty_ Ev alu a tiorLRe por_LS e c_tton1R Reficle11cy; 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 580
!i-submittals that is to be maintained by the licensee.
RESPONSE
CECO's existing diesel generator reliability program will be reviewed to ensure conformance to the guidance in Regulatory Guide 1.155.
A complete description of this reliability program, together with any required modifications, will be included with the station's SB0 backup documentation.
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l ZNLD/902/10
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