ML20045B137

Responds to NRC Bulletin 93-002, Debris Plugging of ECC Suction Strainers. Use of Temporary Fibrous Air Filters within Primary Containment (Drywell) Identified

ML20045B137
Person / Time
Site:	Pilgrim
Issue date:	06/07/1993
From:	Boulette E BOSTON EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
BECO-LTR-93-73, IEB-93-002, IEB-93-2, NUDOCS 9306160333
Download: ML20045B137 (3)

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[f HRCB 93 BOSTON EDISON Pdgrim Nuclear Power Staten Rocky Hal Road Plymouth, Massachusetts 02360 June 7 , 1993 BEco Ltr. 93-73 E. T. Boulette, PhD Senior Vce President-Nuclear U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555 Docket No. 50-293 License No. DPR-35 Response to NRC Bulletin 93-02

" Debris Plugging of Emergency Core Cooling Suction Strainers" NRC Bulletin 93-02 requested all holders of operating licenses for nuclear power reactors to immediately upon receipt of the bulletin take the following actions:

• Identify fibrous air filters or other temporary sources of fibrous material not designed to withstand a loss-of-coolant accident (LOCA) that are installed or stored in primary containment.

• Take any immediate compensatory measures which may be required to assure the functional capability of Emergency Core Cooling Systems (ECCS).

• Take prompt action to remove any such material from the primary _ containment.

For facilities in shutdown at time of receipt of the bulletin the NRC requested all such material be removed prior to plant restart.

Boston Edison Company's review in response to Bulletin 93-02 identified the use of temporary fibrous air filters within primary containment (Drywell). The temporary filters are utilized to maintain cleanliness of the cooling coils of unit coolers during plant outages when primary containment is open. The filters are procedurally installed following plant shutdown and are procedurally removed prior to plant restart in accordance with Procedure PNPS 3.M.4-59, "Drywell Unit Cooler Roughing Filter Installation and Removal". Removal of the fibrous material was also confirmed during performance of Procedure PNPS 3.M.1-38, " Primary Containment -

Closeout". Temporary fibrous materials are not stored within the primary containment.

At the time of issuance of Bulletin 93-02, Pilgrim Nuclear Power Station (PNPS) was shut down with refueling outage nine (9) in progress. Prior to plant restart all temporary fibrous material (roughing filters) was removed from the primary containment. I 9306160333 930607 PDR ADOCK 05000293 5

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j BO$TONEDISONCOMPANY U.S. Nuclear Regulatory Commission Page 2 The location and quantity of fibrous material utilized during outages within the primary containment is listed below.

LOCATION OVANTITY PURPOSE Drywell 9 foot elevation 2 each 60" X 84" Roughing Filter Drywell 9 foot elevation 2 each 36" X 72" Roughing Filter Drywell 35 foot elevation 1 each 36" X 72" Roughing Filter Drywell 41 foot elevation 1 each 36" X 42" Roughing Filter ,

Drywell 81 foot elevation 8 each 20" X 30" Roughing Filter Pilgrim Station has a Mark I containment and the Emergency Core Cooling Systems take their suction from the torus (i.e., suppression pool). Unlike the open suppression pool of the Mark III containments, the torus is closed except for the vent pipes that connect the torus to the drywell. This design helps to minimize the entry of dust, dirt, and other foreign material into the suppression chamber.

Cleanliness of the torus at PNPS has not been an issue. The torus was drained, thoroughly cleaned and repainted during Refueling Outage (RF0) No. 7 (1986-1988).

The torus was again inspected and cleaned during RF0 No. 8 (1991) utilizing under water divers and vacuum pump. During the current outage (RF0 No. 9) the torus, including the vent pipes and vent header, was inspected by walkdown. No fibrous material was found.

In summary, Boston Edison Company neither utilizes nor stores temporary fibrous material within primary containment during plant operation. Prior to plant operation, all fibrous material is confirmed rem ved from primary containment.

Cleanliness of the torus (suppression pool) is periodically confirmed. Based on the above, proper controls are in place at PNPS to preclude events similar to those referenced in Bulletin 93-02. This completes our response to this bulletin.

dw E. T. Boulette Commonwealth of Massachusetts)

County of Plymouth)

Then personally appeared before me, E. T. Boulette, who being duly sworn, did state that he is Senior Vice President - Nuclear of Boston Edison Company and that he is duly authorized to execute and file the submittal contained herein in the name and  ;

on behalf of Boston Edison Company and that the statements in said submittal are true to the best of his knowledge and belief. '

My commission expires: h M ,j_f h w DKIE NOTARY PU LIC

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BOSTON EDISON COMPANY  ;

U.S. Nuclear Regulatory Commission Page 3

.1 cc: Mr. R. B. Eaton J Div. of Reactor Projects 1/11  !

Office of NRR - USNRC .

One White Flint North - Mail Stop 14D1  :

11555 Rockville Pike i Rockville, MD 20852 l  !

U.S. Nuclear Regulatory Commission l Region I j 475 Allendale Road  :

King of Prussia, PA 19406 l Sr. NRC Resident Inspector Pilgrim Nuclear Power Station  !

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