ML20069B931
| ML20069B931 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 03/14/1983 |
| From: | Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8303170339 | |
| Download: ML20069B931 (3) | |
Text
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PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O'. BOX 8699 PHILADELPHI A. PA.19101 SHIELDS L DALTROFF aLecra c r$ c som March 14, 1983 Re:
Docket Nos. 50-277 50-278 Mr. John F. Stolz, Chief Operating Reactors Branch #4 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D. C.
20555
SUBJECT:
Peach Bottom Proposed Technical Specification on Degraded Grid Voltage Protection Ref.:
Letter to J. F. Stolz from S. L. Daltroff, dated' October 29, 1982
Dear Mr. Stolz:
In our referenced letter on Degraded Grid Voltage Protection for Peach Bottom, we provided justification for a proposed functional test frequency.
Due to a change in the system design, we have determined the need for a change in our proposed functional test. frequency.
This letter provides the reason for the system design change, and proposes a new j
functional test frequency.
An additional auxiliary relay (Aux 2) and its associated contacts, as shown on the attached schematic, have been added to i
each tripping scheme to facilitate surveillance testing of the l
-systems while the units are at power.
The additional relay provides the additional contacts needed for interlock in the breaker closing circuit and also provides a contact needed for surveillance testing.
l This additional relay, however, has the effect of I
creating a circuit of trip logic in addition to the protective l
relay trip channel.
Since the surveillance test for the degraded j
voltage protective relays will include a functional testing interval for the protective relays and trip logic, we propose a six month functional testing interval for the protective relays and trip logic.
If the protective relay trip channels are functionally tested every six months, we have determined that the ft,g/I 8303170339 830314 l
PDR ADOCK 0500027 l
..~..
Mr. J.
F.
Stolz, Chief Page 2
overall reliability of the system exceeds 0.99999, which is the reliability goal of the RPS and ECCS instrumentation.
This design reliability is based on assuring operation of any of the three protective relays and associated auxiliaries protecting each bus, on three of the four emergency buses per unit.
Surveillance testing of the degraded voltage relays and the associated trip logic every six months will satisfy the reliability goal and make the trip logic testing interval conform to that of similar ECCS circuits.
The six month test interval is appropriate from a reliability viewpoint.
A requirement for more frequent tecting at full power introduces an additional risk of unanticipated transients with little additional benefit.
The proposed degraded grid voltage modifications and testing frequencies were presented to the Operations and Safety Review Committee at its February meeting.
The Committee has approved the modifications and testing programs and the submission of an appropriate Technical Specification Amendment.
If you have any questions or require additional information, please don't hesitate to call.
Very truly yours, s
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