ML19260D371
| ML19260D371 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 01/30/1980 |
| From: | Andognini G BOSTON EDISON CO. |
| To: | Ippolito T Office of Nuclear Reactor Regulation |
| References | |
| 80-22, NUDOCS 8002080619 | |
| Download: ML19260D371 (3) | |
Text
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BOSTON EDISDN C1MPANY oENERAL orriCEs 800 GOYLETON STRECT GOETON, MASEACNuSETTs o2199
- o. CAR 6 ANDOONING S U PE RI NT END E N T NUCLEAR OPERAflONS DEPARTMENT January 30, 1980 BEco. Ltr. #80-22 Mr. Thomas A. Ippolito, Chief Operating Reactore '4 ranch #3 Division of Operating Reactors Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, D. C.
20555 License No. DPR-35 Docket No. 50-293 Additional Information for Containment Purge and Vent System
Reference:
(a) USh1C Letter to Boston Edison Company dated November 28, 1979.
Attachment:
(a) Responses to Contairment Purge and Vent System Mechanical Questions
Dear Sir:
In Reference (a) you requested additional information concerning containment purging and venting which would enable you to complete your review of this subj ect in the mechanical area. Attachment (a) provides responses to your questions, describes our continuing actions and outlines our subsequent plans.
If you should have any further questions please contact us.
Very truly yours, 1934 084 4
Attachment
\\
f 8002080
Pa);e 1 of 2 Attachment A Mechanical Ouestions on Containment Purge & Vent System 1.
With regard to the containment purge system (18" and 20" lines), provide the following information:
Discuss the provisions made to ensure that isolation Valve closure.will a.
not be prevented by debris which could potentially become entrained in the escaping air and steam.
Response 1.a A Plant Design Change Request (PDCK) is being prepared by our Engineering Department which will provide detailed instructions for installing baffle plates on the Grywell pipe penetrations to prevent entry of potentially harmful debris.
We do not plan to install baffles on the torus pipe ends as modifica: ions are presently being made, as part of the Mark I Contain-ment Program, which will prevent the possibility of attachments breaking away and entering these lines.
b.
Provide an analysis to demonstrate the acceptability of the provisions made to protect structures and safety-related equipment; e.g.,
- fans, filters, and ductwork, located beyond the purge system isolation valves against loss of function from the environment created by the escaping air and steam.
Resoonse 1.b.
Our Engineering Department has completed an in-house analysis of the acceptability of the provisions made to protect structures and equipment from the environment created by escaping air and steam. Preliminary results have revealed a potential for over-pressurization of parts of the down-stream ductwork if both isolation valves are full open during a LOCA situation.
The following actions were immediately initiated.
(1) In-house analysis continued to ascertain which actions may be taken to prevent an over-pressurization from occurring e.g.
limiting maximum opening position of the valves during operation.
(2) Teledyne Engineering Services was immediately contracted to per-form an independent analysis of the system. Based upon their results they have been instructed go develop operating recommenda-tions and design modifications which would assure system integrity.
Their report will be completed prior to March 1, 1980.
For the containment purge isolation valves, specify the differential c.
pressure across the valve for which the maximum leak rate occurs.
Provide test results (e.g., from vendor tests of leakage rate versus valve dif ferential pressure) which support your conclusion.
Response 1.c.
The containment purge isolation valves are butterfly valves with rubber compression. eats designed by Rockwell and are no longer manufactured.
Rockwell was contacted and informed us that the manufacturer's test re-sults are not available.
There are, test procedur q{gbq}{p{peveloped
Page 2 of 2 by our Engineering Department to obtain data to support our expectations that the leakage is approximately directly pro-portional to the dofferential pressure and that the maximum leakage would occur at the maximum dp.
Summary All analyses will be completed and their results available before March 1, 1980.
Testing will be conducted on ah axpedited basis and any required design modifica-tion completed before the end of the refueling outage.
1934 086