ML20057C383
| ML20057C383 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 09/22/1993 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20057C381 | List: |
| References | |
| NUDOCS 9309280293 | |
| Download: ML20057C383 (4) | |
Text
pH MCg nclosure UNITED STATES
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2 NUCLEAR REGULATORY COMlvt!,S10W WASHINGTON, D.C. 20555-0001 sy j SUPPLEMENTAL SAFETY EVALUA 1QM BY THE OFFICE OF NUCLEAR REACT 0_ < REGULATION STATION BLACK 0UT RULE (10 CFR 50.63)
BALTIM0RE GAS AND ELECTifC COMPANY CALVERT CLIFFS NUCLEAR POWER PLANT. UNITS 1 and 2 DOCKET NOS. 50-31 'LUH
1.0 INTRODUCTION
The NRC staff's safety evaluation (SE) and sul plemental safety evaluation (SSE) pertaining to the Baltimore Gas and Elec tric Company's (the licensee's) responses to the Station Blackout (SB0) Rule,10 CFR 50.63, were transmitted to the licensee by letters dated October 10, 1190, and February 12, 1991, respectively.
The staff's SSE found the liter see's proposed method of coping with an SB0 to be acceptable (ac-independent a id I hour alternate ac (AAC) power source based on the commitment to install two safety-related emergency diesel generators (EDGs).)
Subsequently, the licensee submitted a revise < response dated July 7, 1993, to the SB0 Rule.
The licensee, in its revised risponse, indicated that instead of installing two safety-related EDGs as orig nally proposed (total of five for the site), one safety-related EDG (total i f four for the site) and one nonsafety-related EDG will be installed. The nonsafety-related EDG will be used as the AAC power source during an SB0 evint.
The staff previously accepted the Calvert Clif fs Unit I refueling outage scheduled for June 1996 as the final completic i date for implementation of the SB0 Rule. The staff considers this date to re.tain in effect.
This SSE is based primarily on the July 7,1993, submittal (hereafter, revised submittal). However, the licensee's previous risponses to the SB0 Rule and the staff's previous evaluations, which are not changed by this SSE, remain valid and in effect.
2.0 EVALUATION The following items are discussed in the order th.t they were addressed in the July 7, 1993, submittal.
2.1 Station Blackout Duration (SE Section 2.1)
In its February 12, 1991, SSE (Section 2.1), the sttff accepted an SB0 duration of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, based on a plant ac power t esign characteristic Group "P2," an emergency ac (EAC) power configuration Grou "C" (installing two safety-related EDGs resulting in two dedicated safet,'-related EDGs for each 9309280293 930922 ADDCK0500g7 PDR P
unit plus one spare safety-related EDG) with a target EDG reliability of 0.975.
The licensee, in its revised submittal, stated that the EAC power configuration Group is "C" by installing one safety-related EDG at the site.
Based on its review, the staff finds that the EAC power configuration Group is "C."
The installation of one safety-related EDG results in two dedicated safety-related EDGs for each unit not credited as an AAC power source, with one EDG required to operate safe shutdown equipment following a loss of offsite power. Hence, the SB0 coping duration of 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, based on a plant ac power design characteristic Group "P2," an EAC power configuration Group "C,"
and a target EDG reliability of 0.975, is not affected by the installation of or a safety-related EDG and one nonsafety-related AAC EDG.
2.2 Alternate AC (AAC) Power Source (SE Section 2.2)
The licensee stated that they plan to add a nonsafety-related 5000 Kw SACM EDG as AAC power source which is identical to the one procured for the safety-related application.
The AAC EDG and its auxiliaries are procured as safety-related, however, they will be installed in a nonsafety-related building and they will not be maintained as safety-related.
The testing program, identical to the one described for safety-related SACM EDG with the exception of the automatic start and load tests, will be imposed on the nonsafety-related EDG.
The EDG will have capability to power the safe shutdown loads on either unit during an SB0 event.
It will be designed to meet the criteria of NUMARC 87-00, Appendix B.
Quality assurance will be in accordance with the criteria of Regulatory Guide 1.155, Appendix A.
Also, this EDG will be manually started and loaded to power all of the SB0 loads within one hour during an SB0 event.
Based on its review, the staff finds that the nonsafety-related EDG is a fully capable AAC power source.
2.3 Procedures The licensee stated that emergency operating procedure (EOP)-7, Station Blackout, describes the actions required to respond to an SB0 event based on the guidance given in Section 4.2.1 of NUMARC 87-00. The licensee further indicated that E0P-7, at present, addresses an ac-independent coping scenario, since the AAC power source is not installed yet. The procedure will be changed as the safety-related EDG and the AAC power source (nonsafety-related EDG) are installed.
The staff did not review the S80 response procedure. However, the staff finds that the SB0 response procedure, as described above, is acceptable.
3.0
SUMMARY
AND CONCLUSION The licensee initially proposed to add two safety-related EDGs to change the EAC Group from "D" to "C" resulting in two dedicated safety-related EDGs per unit with the spare EDG used as an AAC power source during a 580 event. The staff's October 10, 1990 SE and February 12, 1991 SSE found this to be
acceptable. The licensee submitted a revised response dated July 7, 1993, to the SB0 Rule.
The staff has evaluated this revised response, as detailed above, and finds it to be acceptable.
The staff previously accepted the Calvert Cliffs Unit I refueling outage scheduled for June 1996 as the final completion date for implementation of the SB0 Rule. The staff considers this date to remain in effect. Therefore, the licensee should take the necessary actions to complete the modifications for compliance with the SB0 Rule prior to start-up from the 1996 Unit I refueling outage. The supporting documentation should be maintained by the licensee for possible future NRC audit.
Principal Contributor:
A. Pal Date:
September 22, 1993 r
I i
i t
1
3 Mr. Robert E. Denton September 22, 1993 modifications and changes necessary to be in compliance with the SB0 Rule.
All of the supporting documentation which provides the basis for compliance i
with the SB0 Rule shall be maintained in an auditable form.
This completes our actions related to the above referenced TACs.
Sincerely, Original signed by:
Daniel G. Mcdonald, Senior Project Manager Project Directorate I-I Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation
Enclosure:
Supplemental Safety Evaluation 4
cc w/ enclosure:
See next page Distribution:
Docket File NRC & Local PDRs PDI-I Reading SVarga JCalvo RAcapra CVogan DMcDonald OGC ACRS (10) i CCowgill, RGN-I CBerlinger, 7/E/4 APal, 7/E/4 i
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OFFICIAL RECORD COPY FILENAME: CC86999.LTR l
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