ML20045A926
| ML20045A926 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 06/08/1993 |
| From: | Frizzle C Maine Yankee |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| CDF-93-92, IEB-93-002, IEB-93-2, MN-93-61, NUDOCS 9306150313 | |
| Download: ML20045A926 (2) | |
Text
MaineYankee C~~
5tE LIABLE f LECTRICITY FOR MAINE SINCE 1977 Chares D Frtrile Edison Drive Preudent Augusta. Maine 04336 (207) 622-4868 June 8, 1993 MN-93-61 CDF-93-92 UNITED STATES NUCLEAR REGULATORY COMMISSION Attention: Document Control Desk
' Washington, DC 20555
References:
(a) License No. DPR-36 (Docket No. 50-309)
(b) NRC Bulletin 93-02, " Debris Plugging of Emergency Core Cooling Suction Strainers", dated May 11, 1993
Subject:
Response to NRC Bulletin 93-02: Debris Plugging of Emergency Core Cooling Suction Strainers Gentlemen:
NRC Bulletin 93-02, Reference (b), notifies licensees of a previously unrecognized potential contributor to the loss of net positive suction head for emergency core cooling pumps during the recirculation phase of a loss of coolant accident. This contributor is identified as fibrous particles originating from air filters and other temporary sources of fibrous materials which are installed or stored in the containment during power operations.
It is postulated that these materials may provide blockage to the flow of water from the recirculation sump should they migrate to the strainers during an accident.
As a consequence of this blockage, the emergency core cooling pumps drawing suction from the sump during the recirculation phase of the accident may experience inadequate net positive suction head.
l In response to this concern, the NRC Bulletin 93-02, Reference (b), requested licensees to perform the following actions:
Identify fibrous air filters or other temporary sources of fibrous material, not l
designed to withstand a LOCA, which are installed or stored in your primary l
containment. Take any iminediate compensatory measures which may be required to assure the functional capability of the ECCS. Take prompt action to remove any such material.
Because of the low probability of a LOCA event, the staff considers removal of this material at tM next shutdown, or within 120 days, whichever comes first, to be sufficientif prompt. If the facility is currently in a shutdown, you are requested to remove such material prior to restart.
Maine Yankee has undertaken and completed a review of such type materials which may be found in our containment during power operations.
We have concluded that Maine Yankee does not store, or have temporarily installed. any fibrous materials inside the containment building which are capable of contributing to this potential problem.
Additionally, we have reviewed the permanently installed filters in our containment in order to assess their stability during an accident.
We find these filters are designed to withstand a LOCA.
9306150313 930609
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I MaineYankee UNITED STATES NUCLEAR REGULATORY COMMISSION MN-93-61 Attention: Docuant Control Desk Page 2 As referred to in Reference (b), an accumulation of corrosion products, dust, and other small foreign material may also contribute to a potential blockage of the recirculation sump strainers.
At Maine Yankee, we have in place procedural requirements to aggressively establish and maintain cleanliness in the containment during power operations. As a portion of these requirements, the sump undergoes a routine periodic inspection for such debris during the operating cycle. Additionally, at the conclusion of each refueling outage, Maine Yankee Management is procedurally required to conduct detailad containment inspections.
During such inspections, procedures require inspecto." to specifically look for materials such as loose insulation, plastic sheeting, tape, label s, etc., in the containment prior to startup. Maine Yankee's procedures stipulate that no uncontrolled material may be stored or left in the containment.
Our review of the requested action of Reference (b) concludes that Maine Yankee currently has in place a housekeeping and inventory control program for the containment that addresses the concerns identified in the NRC Bulletin 93-02.
With respect to the reporting requirements identified in Reference (b), Maine Yankee considers this letter to adequately address all three requirements.
Please contact us if you require additional information.
Very truly yours, M
.y a Charles D. Frizzle President and Chief Executive Officer CDF/ jag c:
Mr. Thomas T. Martin Mr. E. H. Trottier Mr. Charles S. Marschall Mr. Patrick J. Dostie STATE OF MAINE Then personally appeared before me, Charles D. Frizzle, who being duly sworn did state that he is President and Chief Executive Officer of Maine Yankee Atomic Power Company, that he is duly authorized to execute and file the foregoing response in the name and on behalf of Maine Yankee Atomic Power Company, and that the statements therein are true to the best of his knowledge and belief.
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