ML18095A464

Forwards Revised Response to NRC Bulletin 88-004 Re Potential pump-to-pump Interaction.Util Pursuing Permanent Solution to Issue & Will Implement Appropriate Permanent Field Change by End of Unit 1 10th Refueling Outage

ML18095A464
Person / Time
Site:	Salem
Issue date:	08/31/1990
From:	Labruna S Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
IEB-88-004, IEB-88-4, NLR-N90172, NUDOCS 9009120100
Download: ML18095A464 (6)

Text

Public Service Electric and Gas Company Stanley LaBruna Public Service Electric and Gas Company P.O. Box 236, Hancocks Bridge, NJ 08038 609-339~4800 Vice President - Nuclear Operations AUG 3 1 1990 NLR-N90172 United States Nuclear Regulatory Commission Document Control Desk Was.hington, DC 20555 Gentlemen:

SUPPLEMENTAL RESPONSE TO BULLETIN 88-04 SALEM GENERATING STATION UNITS NOS. 1 AND 2 DOCKET NOS. 50-272 AND 50-311 Public Service Electric and Gas Company (PSE&G) hereby submits its revised response to Bulletin 88-04. As a result of the Integrated Performance Appraisal Team (IPAT) inspection

• concern, PSE&G performed an additional review of the forenamed bulletin.

The results of the follow-up review and the actions taken by PSE&G are provided in the attachment.

Should you have any further questions with regard to this submittal, please do not hesitate to contact us.

Sincerely, Attachment

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._; v ~ .j 9009120100 900831 PDR ADOCK 05000272 .

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Document Control Desk 2 NLR-N90172 AUS a 1 1990 c Mr. J. c. Stone Licensing Project Manager Mr. T. Johnson Senior Resident Inspector Mr. T. Martin, Administrator Region I Mr. Kent Tosch, Chief New Jersey Department of Environmental Protection Division of Environmental Quality Bureau of Nuclear Engineering CN 415 Trenton, NJ 08625

REF: NLR-N90172 Bulletin 88-04 STATE OF NEW JERSEY )

) SS.

COUNTY OF SALEM )

s. LaBruna, being duly sworn according to law deposes and says:

I am Vice President - Nuclear Operations of Public Service Electric and Gas Company, and as such, I find the matters set forth in our letter dated , concerning the Salem Generating Station, Unit Nos. 1 and 2, are true to the best of my knowledge, information and belief.

Subscribe~nd sworn to before me this . ,J t1 day of tf!,t~ , 1990 J (/

.*~~ ~~L lARAINE Y. BFARD Notary Public of New Jim~y My Commission Expire1May 11 1~9l My Commission expires on

e*

ATTACHMENT

Response

NRC Bulletin 88-04 requested licensees to investigate and correct, as applicable, two mini-flow design concerns. The first concern involved the potential for dead-heading one or more pumps in safety-related systems that have a mini-flow line common to two or more pumps or other piping configurations that do not preclude pump-to-pump interaction during mini-flow operation.

The second concern is whether or not the install~d mini-flow capacity was adequate for even a single pump in operation.

PSE&G's initial response to the Bulletin indicated that the Residual Heat Removal (RHR) pumps had individual recirculation lines and therefore, we eliminated the first NRC concern.

However, during its review of NRC Bulletin 88-04, the pump-to-pump interaction potential in the RHR system was not recognized by PSE&G.

During the IPAT team inspection, PSE&G was questioned about the potential RHR pump-to-pump interaction concern. PSE&G's initial response was to indicate that individual recirculation lines were provided for Salem's RHR pumps. After further discussion with the IPAT team, PSE&G acknowledged the omission of the "potential" pump to primp interaction, and initiated an immediate investigation of the concern. This investigation involved contacting numerous utilities with similar RHR system configurations, a complete review of all available IST surveillance results, a fluid hydraulic review of the system by in-house engineering, and discussions regarding potential Emergency Operating Procedure (EOP) changes with Westinghouse.

The initial review identified that this condition was precluded on Salem Unit 2 because of the location of the installed suction check valves (2RH76 and 2RH75). These check valves prevent flow between the suction of the pumps. Since the suction side communication is isolated, no recirculation flow will pass through the open discharge cross-connect line via the RH19 valves. These suction side check valves essentially assure the two RHR loops will remain isolated from each other.

PSE&G is certain that Salem Unit 2 is not susceptible to this condition and will be further discussing this conclusion with Region I.

• However, Salem Unit 1 was determined to be potentially susceptible as no suction side check valves are presently installed.

PSE&G notified the office of Nuclear Reactor Regulation (NRR) of this omission in the original response to Bulletin 88-04 and committed to revise that response.

Review of IST data indicated that the two Salem Unit 1 RHR pumps showed very similar performance data.

NLR-N90172

Calculation S-1-RHR-MDC-0537 was performed by in-house engineering personnel to demonstrate that dead-heading of the RHR pumps was not a concern for Salem Unit 1. The results of this calculation determined the recirculation flowrates, which would be expected for the weaker pump, at various differences in the Total Developed Head (TDH) for the pumps. The results are summarized below:

20 ft. difference between pumps (8.66psid) - total dead-head condition 18 ft. difference between pumps (7.79psid) - results in 63 gpm for weaker pump 15 ft. difference between pumps (6.49psid) - results in 146 gpm for weaker pump 10 ft. difference between pumps (4.33psid) - results in 289 gpm for weaker pump In addition, calculation S-1-RHR-MDC-0544 was performed to determine the length of time that an RHR pump could operate with no recirculation flow. This calculation determined that an RHR pump could operate for 8 minutes with no recirculation flow before sustaining damage. Additionally, information received from

• the pump manufacture (Ingersoll Rand) indicated the RHR pumps could operate for approximately 30 minutes with recirculation flow rate of lOOgpm. Based upon these calculations PSE&G modified Surveillance Procedure, SP(0)-4.0.5~P-RH(ll), to physically evaluate the susceptibility of Salem Unit 1 RHR pumps to this condition and to ensure a TDH between pumps of less than 6.5 psi. The 6.5 psi (-150gpm) was chosen to ensure that adequate recirculation flow would be available to preclude pump damage. This test was performed satisfactorily on June 3, 1990, and it has been incorporated into the normal Technical Specification 4.0.5-P(RH)-11 Surveillance. Additionally, this test will be performed every 92 days until a permanent solution can be implemented. The results of the RHR pump parallel operation test is presented below; No. 11 RHR pump - TDH 177 psid; recirc. flow 535 gpm No. 12 RHR pump - TDH 176 psid; recirc. flow 542 gpm These results clearly demonstrate that with both pumps operating in parallel, the difference* in developed head between the two pumps (lpsi) is not enough to dead-head the pumps. Additionally, the test also indicates flow rates of 500 GPM or more for each pump, while operating in parallel.

NLR-N90172

In addition to the testing, PSE&G has developed an EOP change involving the closure of one of the motor operated valves (RH19s), which cross-ties both loops, to physically separate the loops. This EOP modification has been agreed to by Westinghouse and is supported by a 10 CFR 50.59 safety evaluation. This change has been reviewed and is ready for implementation in the event that future testing indicates unsatisfactory results outside the established acceptance band of 6.5 psi.

PSE&G is aggressively pursuing a permanent solution to this issue and will implement an appropriate permanent field change by the end of the Unit 1 10th refueling outage.

NLR-N90172