ML20076N584
| ML20076N584 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 10/28/1994 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML20076N569 | List: |
| References | |
| NUDOCS 9411100163 | |
| Download: ML20076N584 (4) | |
Text
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UNITED STATES y
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NUCLEAR REGULATORY COMMISSION f
WASHINGTON, D.C. 20555-0001
'%.....f SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION EMERGENCY DIESEL GENERATORS OUALIFICATION REPORT BALTIMORE GAS AND ELECTRIC COMPANY CALVERT CLIFFS NUCLEAR POWER PLANT. UNIT NO. 2 DOCKET NO. 50.317 1.0 INTP.0 DUCTION On July 21,1988, Part 50 of Title 10 of the Code of Federal Regulations was amended to include a new Section 50.63, entitled, " Loss of All Alternating Current Power," referred to as the station blackout (SBO) rule. The SB0 rule requires that each light-water cooled nuclear power plant be able to withstand and recover from an SB0 of specified duration.
The SB0 rulo also requires that information defined in the rule be provided to the staff for review.
BG&E responded to the requirements of the rule and the staff approved its response by letter dated February 12, 1992. The staff's approval included the addition of two new safety-related Class-lE emergency diesel generators (EDGs).
BG&E submitted a revised response to the 580 Rule on July 7, 1993. One of the initial commitments approved by the NRC staff in its safety evaluation (SE) was to install two safety-related EDGs, as noted above, which would have resulted in a total of five safety-related EDGs at t'ie site. The revised response changed that commitment to add one safety-r alated and one nonsafety-related EDG.
The nonsafety-related EDG will be utilized as an alternate ac power source during SB0 conditions. The final configuration will include two dedicated safety-related EDGs per unit. The revised response was approved by SE dated September 22, 1993.
The three existing safety-related EDGs are being modified to increase their rated capacity from 2500 KW to 3000 KW which will enhance the overall reliability of the onsite electrical power distribution system.
By letter dated August 4,1994, BG&E requested a temporary exemption to GDC-2 to perform the initial upgrading on the Unit 2 EDG No. 21.
The exemption is necessary because a steel missile door will have to be periodically removed in order for the work to be performed at various stages of the upgrade. During the periods of time when the missile protection door is removed, portions of support systems for the remaining EDGs (Nos. 11 and 12) will be exposed to postulated missiles which could be generated by natural phenomena. The EDGs Enclosure 9411100163 941028 PDR ADOCK 05000317 P
4 are required to be operable to support the operation of Unit I and the shutdown or refueling of Unit 2.
The requested exemption is for the duration of the Unit 2 refueling outage (RFO-10) which is scheduled from March 17, 1995, to late May 1995. By letter dated February 23, 1994, a similar temporary exemption was issued by the Commission to support the upgrade of the Unit 1 EDG No. II.
2.0 EVALVATION While producing some increase in missile interaction risk during Unit No. 1
[
operation and the shutdown or refueling of Unit No. 2, it will be minimal due to the short periods of time that the missile door will be removed.
The steel missile door will be required to be removed about four times during the outage. The licensee estimates that each of the removals will last for about 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, which will result in a total removal time of about 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> during the Unit 2 scheduled 65 day RF0-10. Thus, the likelihood of tornado-generated or other high wind-generated missile damage which could affect the exposed portions of the support systems for the operable EDGs is low.
Even though the added risk is small, BG&E is providing compensatory action to assure the safe operation of Unit No. 2 and safe shutdown or refueling of Unit No. I during the short periods of time when the missile door will be removed.
A concerted effort will be made to reinstall-the missile door if a tornado watch or hurricane watch is issued or if sustained winds are predicted to be greater than 50 miles / hour at the site in accordance with the plant site Emergency Response Implementation Procedure 3.0, Attachment 17. This will not only encompass tornado conditions, but other severe weather conditions. The only factor which would impede the reinsta11ation of the missile door would be to ensure the safety of the individuals performing the reinsta11ation.
However, based on previous responses to severe weather conditions, the NRC staff has noted that BG&E has performed the necessary preparatory actions for the impending weather prior to conditions which could compromise personnel safety.
The staff has reviewed the licensee's proposed exemption to GDC-2, including the compensatory measure, and concluded that the likelihood of missile damage to the operable EDGs portions of the support systems which would not be protected during short periods of time is small during the period for which the requested exemption would apply.
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3.0 CONCLUSION
Based on its review, the staff has concluded that the licensee's proposed j
temporary exemption to GDC-2 should be granted. This conclusion is based on the low probability of missile generation during the short period of time for which the exemption would apply and the compensatory measures that will be in place.
Principal Contributor:
D. Mcdonald Date: October 28, 1994 i
l
R. Denton Occober 28, 1994 GDC-2, for the Calvert Cliffs Nuclear Power Plant, Unit Nos. I and 2, to allow temporary removal of the steel missile door which is necessary for the i
upgrading of the Unit 2 EDG No. 21 during RF0-10.
j A safety evaluation supporting the above exemption is enclosed. Also, a copy j
of the exemption is being forwarded to the Office of Federal Register for publication.
l Sincerely, Original signed by:
)
Ledyard B. Marsh, Director Project Directorate I-l Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Docket Nos. 50-317 and 50-318
Enclosures:
1.
Exemption 2.
Safety Evaluation cc w/encls: See next page DISTRIBUTION:
Docket File.
C. Vogan PUBLIC D. Mcdonald PDI-l Reading 0GC W. Russell /F. Miraglia, 012/G/18 E. Jordan, D/AE0D R. Zimmerman, 012/G/18 G. Hill (4)
R. Spessard, D/DRIL, MNBB 3701 ACRS (10)
J. Lieberman, D/0E, 07/H/5 OPA i
S. Varga OC/LFDCB l
J. Zwolinski W. Dean, EDO, 017/G/21 i
L. Marsh C. Cowgill, RGN-I
- See previous concurrence DOCUMENT NAME: G:\\CCl-2\\CC90170.EXE To receive a copy of this document, indicate in the box: "C" = Copy without enclosures *E* = Cony with encl [sures "N* = No copy j
OFFICE LA:PDI-1l6 PM:PDI-l l6
- 0GC l D:PDI-1 DD 4t',
D4CRP/M NAME CVogancu /.
DMcDonald:smm LMarsh i F JZwol)hski 4Vart a' DATE 10/R.1/94 '13% 10/M94 09/22/94 10/ 2//94 09/g'/94 M&/ht/94 0FFICIAL RECORD COPY t