ML18106A972

Provides 180-day Response to GL 98-02, Loss of Reactor Coolant Inventory & Associated Potential for Loss of Emergency Mitigation Functions While in Shutdown Condition.

ML18106A972
Person / Time
Site:	Salem
Issue date:	11/18/1998
From:	Storz L Public Service Enterprise Group
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-98-02, GL-98-2, LR-N980468, NUDOCS 9811300141
Download: ML18106A972 (8)

Text

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Public Service Electric and Gas Company Louis F. Storz Public Service Electric and Gas Company P.O. Box 236, Hancocks Bridge, NJ 08038 609-339-5700 Senior Vice President - Nuclear Operations NOV 18 1998 LR-N980468 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 Gentlemen:

RESPONSE TO GENERIC LETTER 98-02 LOSS OF REACTOR COOLANT INVENTORY AND ASSOCIATED POTENTIAL FOR LOSS OF EMERGENCY MITIGATION FUNCTIONS WHILE IN A SHUTDOWN CONDITION ,

SALEM GENERATING STATION FACILITY OPERATING LICENSE NOS. DPR-70, DPR-75 DOCKET NOS. 50-272, AND 50-311 This letter provides the 180-day response to Generic Letter 98-02 for the Salem Generating Station. Public Service Electric and Gas Company (PSE&G) has reviewed the generic letter requirements, and provides its response in attachment 1 to this letter.

Should you have any questions or comments on this transmittal, do not hesitate to contact us.

Attachment (1)

Affidavit

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Document Control Desk NOV 18 1998 lR-N980468 C Mr. H. J. Miller, Administrator - Region I U. S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Mr. P. Milano, Licensing Project Manager - Salem U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 14E21 Rockville, MD 20852 Mr. S. Morris USNRC Senior Resident Inspector (X24)

Mr. K. Tosch, Manager IV Bureau of Nuclear Engineering 33 Arctic Parkway CN 415 Trenton, NJ 08625 95-4933

REF: LR-N980468 STATE OF NEW JERSEY)

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COUNTY OF SALEM )

L. F. Storz, being duly sworn according to law deposes and says:

I am Senior Vice President - Nuclear Operations of Public Service Electric and Gas Company, and as such, I find the matters set forth in the above referenced letter, concerning the Salem Generating Stations, are true to the best of my knowledge, information and belief.

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~7' Subscribed and Sworn to before me U1is ~-day of '({/hi. , 1998 DELORIS D. HADDEN Notary Public of New Jersey My Commission Expires My Commission expires on _ _ _ _.... 03"""*.,.,2e=-2..,ooo=------

ATTACHMENT 1 LR-N980468 RESPONSE TO GENERIC LETTER 98-02 LOSS OF REACTOR COOLANT INVENTORY AND ASSOCIATED POTENTIAL FOR LOSS OF EMERGENCY MITIGATION FUNCTIONS WHILE IN A SHUTDOWN CONDITION BACKGROUND:

The U. S. Nuclear Regulatory Commission (NRC) had previously issued Information Notice (IN) 95-03, "Loss of Reactor Coolant Inventory and Potential Loss of Emergency Mitigation Functions While in a Shutdown Condition," on January 12, 1995, to alert licensees of the incident at the Wolf Creek plant. On March 25, 1996, the NRC staff issued a supplement to IN 95-03 that further analyzed the event. This event involved the loss of reactor coolant inventory while the reactor was in a hot shutdown condition.

In the Wolf Creek event, operators were attempting to reborate Residual Heat Removal (RHR) train B, while at the same time maintenance personnel were repacking an RHR train A-to-train B crossover isolation valve. Train Bis re-borated by re-circulating water through a loop that contains the RHR system piping, the Refueling Water Storage Tank (RWST), a containment spray pump, a manual RWST isolation valve, and an RHR system crossover line. When the RWST isolation valve was opened for the reboration process and the train A-to-train B crossover isolation valve was opened for stroke testing, a drain-down path was inadvertently created from the Reactor Coolant System (RCS) to the RWST.

At Wolf Creek, all RHR and Emergency Core Cooling System (ECCS) pump suction lines are tied into a common suction header. When the draindown event occurred, hot RCS water was introduced into this common suction header between the RWST and the RHR and ECCS pumps. This hot water flashed to steam, resulting in a steam/water mixture in the common header. This steam/water mixture could have resulted in steam binding of the suction piping, which could have adversely affected the pumps in both ECCS trains. In addition, steaming through the RWST establishes a containment bypass path flow. These events were primarily caused by personnel errors, poor coordination between operations, maintenance personnel, and inadequate procedures associated with the operation of the RHR system in the shutdown-cooling mode.

On May 28, 1998, the NRC issued Generic Letter (GL) 98-02 "Loss of Reactor Coolant Inventory and Associated Potential for Loss of Emergency Mitigation Functions While In a Shutdown Condition."

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ATTACHMENT 1 LR-N980468 RESPONSE TO GENERIC LETTER 98-02 LOSS OF REACTOR COOLANT INVENTORY AND ASSOCIATED POTENTIAL FOR LOSS OF EMERGENCY MITIGATION FUNCTIONS WHILE IN A SHUTDOWN CONDITION The NRC is concerned about the controls over the conduct of activities during Hot Shutdown conditions that could lead to a similar event as the Wolf Creek event.

In the following text, the NRC's request for information is stated in boldface type as written in the generic letter, followed by the PSE&G response in regular (non-boldface) type.

REQUESTED INFORMATION Within 180 days of the date of this generic letter, addressees are required to perform the following:

1. an assessment of whether your emergency core cooling systems include certain design features, such as a common pump suction header, which can render the systems susceptible to common-cause failure as a result of events similar to the Wolf Creek RCS drain-down event of September 17, 1994; and if this susceptibility is found,

2. prepare, with consideration of plant-specific design attributes, a description of the features of your Appendix B quality assurance program (for example, the methods used to verify valve position, the controls in place to assure compliance with plant surveillance, maintenance, modification and operating procedures, and the adequacy of operator training for such activities) that provide assurance that the safety-related functions of the RHR system and ECCS will not be adversely affected by activities conducted at hot shutdown (such as occurred at Wolf Creek).

If the assessment performed in response to part (1) of the above required information reveals that the susceptibility exists, then the result of the assessment shall be submitted in writing, pursuant to 10 CFR 50.54(f) and 10 CFR 50.4, to the U.S. Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, D.C. 20555-0001, signed under oath or affirmation under the provisions of Section 182a of the Atomic Energy Act of 1954, as amended, with a copy to the appropriate regional administrator and the appropriate NRC resident 2

ATTACHMENT 1 LR-N980468 RESPONSE TO GENERIC LETTER 98-02 LOSS OF REACTOR COOLANT INVENTORY AND ASSOCIATED POTENTIAL FOR LOSS OF EMERGENCY MITIGATION FUNCTIONS WHILE IN A SHUTDOWN CONDITION inspector. The response to part (2) of the above information request need not be submitted to the NRC. However, responses to parts (1) and (2) of the required information shall be kept in a retrievable licensee system that NRC can verify on an as-needed or sample basis.

PSE&G RESPONSE As stated in the generic letter, Public Service Electric & Gas (PSE&G) is limiting its response to those activities that can be performed or occurred during Hot Shutdown conditions. Hot Shutdown, Mode 4, is defined in the Salem Technical Specifications (TS) as any one inclusive combination of core reactivity condition (Keff less than 0.99),

power level (0%), and average coolant temperature (>200°F but less than 350°F).

The activities also irivolve configurations with pipe diameters equal to or greater than 2 inches. These are the activities that potentially could divert Reactor Coolant System (RCS) fluid to the Refueling Water Storage Tank (RWST), resulting in simultaneous drain-down of the RCS and voiding in the suction header for the Residual Heat Removal (RHR) and Emergency Core Cooling System (ECCS) pumps.

Question #1

1. "An assessment of whether your emergency core cooling systems include certain design features, such as a common pump suction header, which can render the systems susceptible to common-cause failure as a result of events similar to the Wolf Creek RCS drain-down event of September 17, 1994; and if this susceptibility is found, ... "

Response

The September 17, 1994 Wolf Creek event in which the RHR system was temporarily lined-up to the RWST, caused about 9000 gallons of RCS inventory to drain to the RWST in about 1 minute. The Wolf Creek alignment had one RHR pump taking suction from the RWST and returning the flow to the RWST through a path with their HV-8716A and HV-8717 valves open. These valves are comparable to Salem's RH19 and 1(2) RH21. This event was discussed in detail in NRC Information Notice 95-03, 3

ATTACHMENT 1 LR-N980468 RESPONSE TO GENERIC LETTER 98-02 LOSS OF REACTOR COOLANT INVENTORY AND ASSOCIATED POTENTIAL FOR LOSS OF EMERGENCY MITIGATION FUNCTIONS WHILE IN A SHUTDOWN CONDITION as well as Institute Nuclear Power Operations (INPO) Operating Experience (OE) 6947 and 7261. As a result of these documents, PSE&G performed a review of the Salem's design and operating procedures. The review of Salem's design and operating procedures was documented in Nuclear Engineering- (NE) 95-1859.

This review, which included a Probability Safety Analysis (PSA) evaluation, determined that the Wolf Creek event was possible at Salem. This determination was made while reviewing operations' procedure S1 (S2).0P-SO.RHR-0001 (Q) "Initiating RHR."

Specifically, a loss of RCS inventory could occur if the manual RH21 valve was not closed or verified closed prior to opening the RH1 and RH2 valves (see attached one-line simplified diagram). Hot RCS inventory could have been diverted to the RWST during the transition from Mode 3 (Hot-Standby) to Mode 4 (Hot Shutdown), if boron concentration is increased in accordance with Attachment 1 of S1 (S2).0P-SO.RHR-0001 (Q), and the RH21 valve is not closed prior to opening the suction valves to the RHR pumps (1 (2)RH1 and RH2 valves) to initiate RHR. The following two possible scenarios were identified within the performance of S1 (S2).0P-SO.RHR -0001 (Q).

a) During the normal transition from Mode 3 to Mode 4, or vice versa, the Salem Technical Specifications require that one loop of RHR must be aligned for ECCS injection, while the remaining loop is aligned for shutdown cooling. If boron concentration of the RHR loop needs to be adjusted attachment 1 of procedure S1 (S2).0P-SO.RHR-0001 (Q) would be used.

b) Similarly, if one RHR loop was out of service for maintenance with the remaining loop in service for RHR cooling, then the system would be pressurized to the RH21 valve. When returning the inoperable system to service, the fill and venting of the system would be done from the RWST and the RH21 valve would remain in its closed position As a result of PSE&G's original investigation, the Salem operations department initiated remedial actions to identify other possible weaknesses and to prevent the scenario from occurring at Salem 1 and 2. Applicable operation procedures were reviewed and determined to be adequate for the prevention of this event at Salem 1 and 2. However, procedure enhancements were recommended. The following procedures were enhanced:

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• ATTACHMENT 1 LR-N980468 RESPONSE TO GENERIC LETTER 98-02 LOSS OF REACTOR COOLANT INVENTORY AND ASSOCIATED POTENTIAL FOR LOSS OF EMERGENCY MITIGATION FUNCTIONS WHILE IN A SHUTDOWN CONDITION 1 S1/2.0P-SO.RHR-0001 (Rev 4), "Initiating RHR."

2 S1/2.0P-PT.RHR-0108 (Rev 6/5), "Differential Pressure Testing of RHR Valves 1(2) RH26, 11(21) RH19, 12(22) RH19, 11(21) SJ49 and 12(22) SJ49."

3 S1/2.0P-AB.RHR-0002 (Rev 3), "Loss of RHR at Reduced Inventory."

The nature of the revisions were not just limited to preventing a large diversion of RCS water into the RWST (by ensuring that valve RH21 would not be opened concurrently with RH1 and RH2), but to be able to detect small leakage past the affected valve (RH21 ). In addition to these procedure enhancements, the loss of RHR event was included in Segment 1 of the 1995/1996 licensed and non-licensed operator training, as well as being covered in the initial license training during the simulator training portion of the abnormal operating procedure for RHR.

As a result of re-evaluating this event due to GL 98-02, procedure S1 (S2).0P-SO.RHR-0001 (Q) has been revised to include additional administrative requirements to ensure that RH1, RH2, and RH21 would not be opened concurrently.

Additionally, in preparation of the upcoming refueling outages in 1999, this event will be included in the 1999 pre-outage Licensed Operator-Training Program.

Question #2

2. prepare, with consideration of plant-specific design attributes, a description of the features of your Appendix B quality assurance program (for example, the methods used to verify valve position, the controls in place to assure compliance with plant surveillance, maintenance, modification and operating procedures, and the adequacy of operator training for such activities) that provide assurance that the safety-related functions of the RHR system and ECCS will not be adversely affected by activities conducted at hot shutdown (such as occurred at Wolf Creek).

Response

As requested in GL 98-02, the response to part (2) will be available on site for NRG review.

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