ML20106E867
| ML20106E867 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 10/24/1984 |
| From: | Harrington W BOSTON EDISON CO. |
| To: | Vassallo D Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.E.4.2, TASK-TM 84-181, IEB-79-08, IEB-79-8, NUDOCS 8410300152 | |
| Download: ML20106E867 (2) | |
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f mOSTON EDISOy COMPANY B00 BOYLSTON STREET BOSTON, MASSACHUSETTS O2199 October 24, 1984 wituAu o. wAnniwaTOw BEco 84-181 a...............
Mr. Domenic B. Vassallo, Chief Operating Reactors Branch #2 Division of Licensing Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D. C.
20555 License No. DPR-35 Docket No. 50-293 Supplemental Response to IE Bulletin 79-08 and NUREG 0737. Item II.E.4.2 IE Bulletin (IEB) 79-08 and Item II.E.4.2 concerned containment integrity.
Boston Edison (BECo) provided information on both issues in letters of April 25, 1979 and August 21, 1979. This was documented as acceptable by NRC in a letter on IE8 79-08 dated December 18. 1979, and a letter on Category "A" Short Term Lessons Learned, Item 2.1.4, dated April 3,1980.
Item 2.i.4 subsequently became Item II.E.4.2 of NUREG 0737.
In order to address follow items identified by the Pilgrim Station onsite Inspector, BEco has re-reviewed the information provided in its above referenced responses concerning the ability to manually isolate the React r Building Closed Cooling Water (RBCCW) system, the Instrument Air / Nitrogen system and the Torus Make-up system during conditions where an automatic containment isolation signal has been initiated.
This-review indicates that although containment isolation capability is not affected, our earlier responses need to be supplemented with the following information:
RBCCW A portion of the RBCCW, used for drywell cooling, is regarded as non-essential. This portion has a Class I valve in the return line which is capable of remote closure from the Control Room.
The supply line is considered a Class C line in Section 7.3 of the PNPS FSAR since it penetrates containment but has no interaction with the prihtary containment free space or the reactor vessel. In accordance with the original PNPS design criteria a single check valve is provided to attain isolation; this is sufficient for isolation of a class C line.
8410300152 841024 PDR ADOCK 05000293 G
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SQ] TON EDCON COMPANY Mr. Domenic B. Vassallo, Chief October 24, 1984 Page 2 Instrument Air / Nitrogen Supply to the Drywell This non-essential system is not manually isolable by a Class I valve vis-a-vis the drywell.
However, this Class C line is isolable at penetration X-22 by one seismic Class I check valve located outside of primary containment. The nitrogen supply / instrument air is maintained at a pressure in excess of the maximum l
accident pressure expected in the drywell.
If the nitrogen supply / instrument air is reduced to less than containment pressure, the check valve will provide isolation.
This meets the original design criteria of PNPS.
Torus Make-up System
-The torus make-up line is non-essential and ties the condensate transfer system into the RHR test line, which penetrates primary containment at X-2108 and ends below the terus water level. Only one functional Class I check valve is available to isolate the torus make-up line.
Because it penetrates primary containment and interacts with the primary containment free space, the torus make-up system is identified as Class B in Section 7.3 of the Pilgrim Station Final Safety Analysis Report.
For water-sealed Class B lines such as the torus make-up system, the original plant design bases allow one isolation valve in addition to the water seal to meet isolation requirements.
We believe this supplemental information is adcquate to demonstrate that, i
although there is a deviation from the specific requirement to have a remote manual isolation at each of these points, isolation is achieved by the check valves, the original design criteria of Pilgrim Station is met, and containment integrity is ensured. Should you wish any further information or have any questions concerning this submittal, please contact us.
l Very truly yours,
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