ML19347B160
| ML19347B160 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 08/29/1980 |
| From: | Daltroff S PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-80-17, NUDOCS 8010010707 | |
| Download: ML19347B160 (5) | |
Text
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//, c, PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET P.O. GOX 8699 PHILADELPHI A PA.19101 (2m 8415001 swistos L. oAtrnorr necfmCPaoc rose August 29, 1980 Re: Docket Nos. 50-277 50-278 IE Bulletin 80-17 S1 IE Bulletin 80-17 S3 Mr. Boyce II. Grier, Director Office of Inspection & Enforcement Region I US Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406
Dear Mr. Grier:
This letter is in response to IE Bulletin 80-17 Supplement 1,
and Bulletin 80-17 Supplement 3 which concern the failure of 76 of 185 control rods to fully insert during a scram at a BWR.
These responses address items A.1 and 3.2 of Supplement 1 and all items of Supplement 3.
The " Actions to be Taken by Licensees" and our responses are treated sequentially.
The following estimates are for the manhours expended to date in response to Bulletin 80-17 and Supplements 1,
2, and 3.
Manpower Requirements llours Bulletin Response 1540 Corrective Actions 180 Bulletin 80-17 Supplement 1 A.1 Provide to the NRC Regional Office an analysis of the adequacy of the "as-built" SDV systems and associated vent and drain systems, including any identified design deficiencies.
Include copies of verified "as-built" isometric drawings of the SDV and detailed descriptions soloo30?ot 9
Mr. B oy co 11. Grier, Director Page 2 of the remainder of the system, verified to be correct, as part of this analysis.
Response
Our letter dated August 7, 1980 concerning Bulletin o0-17 S1 addressed item A.1, however, at that time we had not completed the analysis of the adequacy of the vent and drain system.
The results of our analysis follow.
We have reviewed the design of the "as-built" scram discharge volume vent and drain systems and have determined that the design is satisfactory and that no design deficiencies exist.
The vent system, which drains to a Clean Radwaste (CRW) line, is positively vented to the atmosphere by means of numerous open funnels on the CRW line and is therefore not affected by any interconnecting systems.
The drain system is positively vented to the atmosphere by means of an above water discharge to the vented waste collector tank.
The drain system and vent system are not interconnected and therefore do not interact.
B.2 Perform a study of potential designs for improving the venting system for the scram discharge volumes and submit a description to NRC by September 1,
1980.
Improvements such as providing a redundant, independent vent for each significant volume in the system or locally installing vacuum breakers close to each such volume should be considered (some plants already include a design which vents locally to atmosphere).
Include an estimate of the time that would be required to accomplish these modifications in your report to be submitted to the NRC Regional Office.
We have been told that meetings have already been scheduled by GE to discuss their proposals in this area with licensees.
Response
The potential modifications that have been identified as a result of the design review of the scram discharge volume vent system are listed below:
a.
Cross-connect the vent line off each scram discharge volume header so that a loss of one ven. path will not preclude venting of both headers.
b.
Provide a normally open vent path from the instrument volume to the discharge volume vent system to prevent air bubble formation in the instrument volume during a scram.
This modifici. tion would improve the reliability of the level indication.
Mr. B oy co 11. Grior, Diroctor Pago 3 c.
Delete the venting modifications that were implemented in response to Bulletin 80-17 S2 (i.e.,
close the 1/4" and 1" holes in the CRW funnel and remove 1" vent standpipe).
This would eliminate the release of reactor water through the holes in the CRW funnel during scram and scram reset without compromising the positive venting of the SDV.
It is anticipated that it would take approximately four months to complete the potential modifications (time includes design and installation) contingent upon the availability of materials.
Bullet.in 80-17 Supplement -3 1
1.
For those plants in which the scram discharge -olume headers are connected to the instrument volume by a 2 inch pipe, within five days of the date of this Bulletin, provide or verify that procedures are in effect to:
a.
Require an immediate manual scram on low control rod drive air pressure with a minimum 10 psi margin above the opening pressure of the scram outlet valves.
b.
Require an immediate manual scram in the event of:
j 1)
Multiple rod drift-in alarms, or 2)
A marked change in the number of control rods with high temperature alarms.
Installation of water level instrumentation in the scram discharge volume with level alarm and continuous level indication in the control room, in response to Item B.1 of IEB 80-17 Supplement No.
1, may provide a basis for relaxation of the time for initiating a manual scran.
Response
Both Peach Bottom Units 2 and 3 have the scram discharge volume headers connected to the instrument volumes by 2 inch pipe.
A new p ro c.e du r e (0T-13, Impending Loss of Ability to Scram) was written to fulfill the above requirements.
2.
In addition, every BWR licensee is requested within five days of the date of this bulletin to provide and implement procedures which require a functional test using water for the instrument volume level alarm, rod block and scram switches after each scrar event, before returning to power.
This procedure should remain in effect until modifications in addition to Item B.1 of IEB 80-17 Supplement No. 1 are completed to
Mr. Boyco !!. Grior, Diroctor Page 4 substantially increase reliability of water level indication in the scram discharge volume (s).
Response
A step was added to tha Reactor Startup Order Procedure (Check-off List GP-2A) to require functional testing, using water, for the instrument volume level alarm, rod block, and scram switches after each scram event before returning to power.
Surveillance test procedures ST 2.4.11 A/C/F and ST 2.4.11 B/D/E for Unit 2,
and ST 2.9.11 A/C/F and ST 2.9.11 B/D/E for Unit 3 were revised to incorporate the necessary requirements for the functional
{
i testing.
l Very truly yours,
,e 4l/'bd~/
cc: US Nuclear Regulatory Commission Office of Inspection & Enforcement Division of Reactor Operations Inspection Washington, DC 20555
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COMMONWEALTH OF PENNSYLVANIA :
ss.
COUNTY OF PHILADELPHIA S.
L.
Daltroff, being first duly sworn, deposes and says:
That he is Vice President of Philadelphia Electric Company; that he has read the foregoing response to IE Bulletin 80-17 and knows the contents thereof; and that the statements and matters set forth therein are true and correct to the best of his knowledge, information and belief.
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$w Sl% ',l f Subscribed and swo to befo me this day of
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