ML20202G232

Responds to IE Bulletin 86-001, Min Flow Logic Problems That Could Disable RHR Pumps, for Unit 2.Single Failure Condition Discussed in Bulletin Does Not Exist at Facility. Related Correspondence

ML20202G232
Person / Time
Site:	Limerick
Issue date:	06/09/1986
From:	Kemper J PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC
To:	Murley T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
References
CON-#386-591 IEB-86-001, IEB-86-1, OL, NUDOCS 8607150342
Download: ML20202G232 (5)

Text

.-

NELATED COMRLVONDEN64 PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 1215)841-4502 JOHN 5 KEMPER v ac E-PR E SID E NT e nsemaa ns=0 amo atse ances June 9, 1986 30dbk. L.

Docket No. 50-353

'l h Dr. T. E. Murley, Administrator fy Region I yg U.S. Nuclear Regulatory Commission 631 Park Avenue C

d[]$ J g King of Prussia, PA 19406 ,

40 1 g N, 7,

Subject:

Response to IE Bulletin 86-01:

(Minimum Flow Logic Problems that Cculd Q ,

Disable RHR Pumps), Dated May 23, 1986 Limerick Generating Station Unit 2 Refe rence : IE Compliance Bulletin 86-01 : (Minimum Flow Logic Problems That Could Disable RHR Pumps), dated May 23, 1986 File: GOVT l-1 (NRC)

Dear Dr. Murley:

The purpose of this letter is to provide the Philadelphia Electric Company (PECo) response to IE Bulletin 86-01 for Limerick Generating Station Unit 2. The bulletin discussed a situation at an operating nuclear power plant in which a single failure occurring under certain accident sequences could result in all Residual Heat Removal (RHR) system minimum flow bypass valves being signaled to close while all other pump discharge valves are also closed. The postulated single failure involves loss of a flow sensing instrument. As indicated in the bulletin, this condition could result in no flow through the RHR pumps and could lead to the pumps running dead headed with potential for pump damage in a few minutes. The actions required by the bulletin are restated below followed by our response:

1. Promply determine whether or not your facility has this single failure vulnerability.

2. If the problem exists, immediately _ instruct all operating shifts of the problem and measures to recognize and mitigate the problem.

8607150342 860609 PDR ADOCK 05000352-G PDR a

. _ = .- -

s. * .

Dr. T. E. Murley June 9, 1986 Page 2

3. Within 7 days of receipt of this bulletin, provide (a) a written report to the NRC which identifies whether or not this problem exists at your facility, (b) if the problem exists, identify the short-term modifications to plant operating procedures or hardware that have been or are being implemented to assure safe plant operations. ,

4. If the problem exists, provide a written report within 30 days of receipt of this bulletin informing the NRC of the schedule for long-term resolution of problems that are identified as a result of this bulletin,

Response

PECo has reviewed the RHR minimum flow logic for Limerick Generating Station Unit 2 and has determined that the single failure condition discussed in IE Bulletin 86-01 does not exist at Limerick Generating Station Unit 2. The RHR system is comprised of four independent and redundant electrical safeguard divisions. There are four RHR pumps; each pump has an associated flow sensing loop installed in the pump discharge line and an associated minimum flow return line to the suppression pool. Each flow sencing loop consists of a flow element, flow transmitter and flow indicating switch. A normally closed motor operated. shutoff valve is provided in each minimum flow return line. Attachment 1 provides a list of the subject pumps, valves, and flow sensing instrumentation.

I When a RHR pump is operating, the ascociated flow sensing loop

" installed in the pump discharge line initiates automatic opening of the shutoff valve in the associated minimum flow return line if adequate flow is not sensed in the pump discharge line. When adequate flow is established, the flow sensing loop initiates automatic closure of the shutoff valve. Each flow sensing loop controls only the shutoff valve associated with that RHR pump and flow se' sing loop.

Each RHR pump, associated flow sensing instrumentation, and associated minimum flow return line and shutoff valve is assigned to a separate electrical safeguard division. Consequently, each pump, associated flow sensing instrumentation, and minimum flow return line and shutoff valve is independent from, separated from, and redundant to each of the other pumps and associated equipment. The single failure of a flow sensing element could result in the loss of only the associated RHR pump. The three remaining RHR pumps will not be affected.

The RHR minimum flow logic problem identified in IE Bulletin 86-01 does not exist at Limerick Generating Station Unit 2. No modifications to plant operating procedures or hardware are required.

e Dr. T. E. Murley June 9, 1986 Page 3 Should you have any questions, or require additional information, please do not hesitate to contact us.

Very truly yours,

_0_ hn . k 6

h

>W Attachment RTG/sjf/668601 Copy to: (See attached Service List) v 1

l l

ATTACHMENT 1

~

Bulletin 86-01 Response June 6, 1986

. Docket No. 50-353 RHR PUMP MINIMUM FLOW PROTECTION LIMERICK GENERATING STATION UNIT 2 RHR Pump Minimum Flow Valve Control Device 2AP202 ffV-2F007A FE-2N014A FT-2N052A FISL-2N652A 2BP202 HV-2F007B FE-2N014B FT-2N052B FISL-2N652B 2CP202 HV-2F007C FE-2NO14C FT-2N052C FISL-2N652C 2DP202 HV-2F007D FE-2N014D FT-2N052D FISL-2N652D W

RTG/sjf/668602 J

~

cc: Troy B. Conner, Jr. , .Esq.

Ann P. Hodgdon, Esq.

Mr. Frank R. Romano Mr. Robert L. Anthony Ms. Phyllis Zitzer Charles W. Elliot, Esq.

Barry M. Hartman, Esq.

Mr. Thanas Gerusky Director, Penna. Emergency Management Agency Angus R. Love, Esq.

David Wersan, Esq.

Robert J. Sugarman, Esq.

Kathryn S. Lewis, Esq.

Spence W. Perry, Eso.

Jay M. Gutierrez, Esq.

Atomic Safety & Licensing Appeal Board Atomic Safety & Licensing Board Panel Docket & Service Section Mr. E. M. Kelly Mr. Timothy R. S. Canpbell N ,

l

.