ML20073E231
| ML20073E231 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 03/30/1983 |
| From: | Lundvall A BALTIMORE GAS & ELECTRIC CO. |
| To: | Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| REF-SSINS-6820 IEB-83-04, IEB-83-4, NUDOCS 8304140391 | |
| Download: ML20073E231 (3) | |
Text
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A BALTIMORE
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GAS AND ELECTRIC CRARLES CENTER.P.O. BOX 1475 BALTIMORE, MARYLAND 21203 ARTHun E. LUNDVALL. Jn.
VICE PRESdDCNT Suppt v March 30,1933 U. S. Nuclear Regulatory Commission Region I 631 Park Avenue King of Prussia, PA 19406 ATTENTION: - Mr. Ronald C. Haynes Regional Administrator
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2, Docket Nos. 50-317 & 50-318 IE Bulletta 83-04: Failure of the Undervaitage Trip Function of Reactor Trip Breakers
Reference:
a) Letter A. E. Lundvall, Jr. to R. C. tiaynes of March 21,1983 Gentlemen:
At the request of the Resident inspector and to preclude any possibility of misinterpretation regarding our response in Reference (a), we are forwarding the attached Enclosure. This Enclosure, duplicates the response portion of item No. I from to Reference (a) with two additional parenthetically enclosed comments, clarifying our previous response.
8304140391 830330 fN PDR ADOCK 05000317 O
1 Mr. R. C. Haynes March 30,1983 Page 2 Should you have further questions regarding the enclosed or previous correspondence, please do not hesitate to contact us.
Very truly yours, f
Vice President - Supply AEL/ LOW /sjb Enclosure STATE OF MARYLAND :
TO WIT:
CITY OF BALTIMORE :
Authur E. Lundvall, Jr., being duly sworn states that he is Vice President of the Baltimore Gas and Electric Company, a corporation of the State of Maryland; that he provides the foregoing response for the purposes therein set forth; that the statements made are true and correct to the best of his knowledge,information, and belief; and that he was authorized to provide the response on behalf of sai poration.
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WITNESS my Hand and Notarial Seal:
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~ Notary Public g
My Commission Expires:
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cc:
J. A. Biddison, Esquire G. F. Trowbridge, Esquire D. H. Jaf fe, NRC R. E. Architzel, NRC
1 ENCLOSURE (1)
ITEM NO.1 Provide a written reply identifying the results of testing performed to verify the operability of the undervoltage trip function independent of the shunt trip function.
RESPONSE
We have completed on-line surveillance testing of the shunt and undervoltage trip mechanisms, independently, to verify operability of each device for both units. The test consisted of manually initiating a trip and measuring the response time for each breaker to reach its protective system trip condition. In all cases, each breaker achieved the protective system trip condition and under actual Reactor Protective System (RPS) trip conditions a RP! trip (considering the redundant nature of the Shunt and U/V devices) would have resulted within the design response times assumed in the Final Safety Analysis Report (0.4 seconds for the most limiting RPS Trip).
Certain undervoltage (U/V) trip devices, measured individually, did not meet the response time criteria used during the test. (An average response time computed from three individual test trials was used to account for variations associated with the testing method. Except for those listed below, only one other test trial exceeded.400 seconds.
The first test trial on TCB-5 for Unit I resulted in a response time of.48 seconds although the average for the three trials was.38 seconds and satisfied the response time criteria established for the test). Those individual U/V trip devices are listed below.
Upon completion of repetetive test, corrective maintenance was performed on the out-of-specification U/V devices and each device was subsequently retested and determined to be within specification.
RESULTS OF TESTING (Maximum response time criteria
< 0.400 sec.)
U/V TRIP DEVICE POST MAINTENANCE TEST TRIALS RESPONSE TIME (SECONDS)
(SECONDS)
TRIP DEVICE NO.
IST 2ND 3RD AVG.
HIGH LOW AVG **
UNIT 1 TCB-1 1.280 4.040 8.600 4.640 0.072 0.048 0.058 TCB-3 0.112 2.300 0.064 0.830 0.048 0.048 0.048 TCB-4 8.470 5.320 0.360 4.720 0.052 0.048 0.050 UNIT 2 TCB-3 24.640 0.064 0.072 8.300 0.048 0.048 0.048 TCB-7
- 0.200 0.160 0.680 0.350 0.088 0.052 0.062 TCB-8 0.712 0.600 1.248 0.850 0.392 0.100 0.235 l
Selected for corrective maintenance to improve response time.
Average of at least five (5) test trials.