IR 05000311/1997011
| ML18102B346 | |
| Person / Time | |
|---|---|
| Site: | Salem  |
| Issue date: | 05/27/1997 |
| From: | Eric Simpson Public Service Enterprise Group |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 50-311-97-11, LR-N970293, NUDOCS 9706030290 | |
| Download: ML18102B346 (9) | |
Text
E. C. Simpson * >;,. .* 'l!1\\\'-I. Public Service Electric and Gas Company * Public Service Electric and Gas Company P.O. Box 236, Hancocks Bridge, NJ 08038 609-339-1700 Senior Vice President
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Engineering MAY 2 7 1997 LR-N970293 United States Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 CORRECTIONS TO THE TECHNICAL SPECIFICATION AMENDMENT 69 SAFETY EVALUATION REPORT SALEM GENERATING STATION UNIT NO. 2 DOCKET NO. 50-311 Gentlemen:
On May 1, 1989, the NRC issued Amendment 69 to the Salem Generating Station Unit 2 Technical Specifications (TS) to establish the system operability requirements for the transfer functions of the Emergency Core Cooling System (ECCS) semiautomatic switchover from safety injection to recirculation during a Loss of Coolant Accident (LOCA) . During an NRC exit meeting for Inspection Report 311/97-11 conducted on April 17, 1997, Public Service Electric and Gas (PSE&G) was informed that certain aspects of the Safety Evaluation Report (SER) for Amendment 69 were not being currently met. The items, as stated in the Amendment 69 SER, that were not being met are as follows: 1. " ... approximately 18 minutes would be available for the operator to perform the necessary switchover manual action ... " (page 2 of the SER) 2. "One of the very early steps in EOP-LOCA-3 is to arm the SJ44 valves so that when the Refueling Water Storage Tank (RWST) low level is reached semi-automatic switchover will occur." (page 3 of the SER) 3. "The operator is instructed by the emergency procedures to monitor sump water level and ensure that the level is increasing before arming the sump isolation valves." (page 3 of the SER) 9706030290 970527 PDR ADOCK 05000311 P PDR IJ>ti. Printed on Recycled Paper 1111111111111111111111111111111111111111
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(-* * Document Control Desk LR-N970293 Discussion of SER Statement 1: * 2 MAY 2 7 1997 After further review of the Amendment 69 SER, PSE&G has identified that statements in the SER quoted above require clarification to agree with the information submitted by PSE&G in support of Amendment 69. In the Amendment 69 SER the NRC stated: "The Salem 2 RWST design incorporates level setpoints which provide approximately 214,000 gallons for injection phase operatio Assuming all ECCS pumps operate at the maximum flow rates, the earliest time after LOCA initiation that switchover will automatically occur is 14 minutes. When semiautomatic switchover is initiated approximately 129,300 gallons would be available in the RWST for the transfe allowanc Again, assuming that all ECCS pumps operate at the maximum flow rate, approximately 18 minutes would be available for the operator to perform the necessary switchover manual action to ensure a continued suction to the charging and safety injection pumps." A review of the references listed in the Amendment 69 SER and a search of other docketed correspondence by PSE&G revealed that the statement, " ... approximately 18 minutes would be available for the operator to perform the necessary switchover manual action ... ," contained in the SER is incorrect as discussed below. Only two documents containing information concerning switchover times were identified by the review of docketed correspondenc These documents were submitted to the NRC on July 17, 1980 and January 5, 1987 (reference 4 and 6 of the Amendment 69 SER, respectively).
In the July 17, 1980 letter, PSE&G states on page 3 of the attachment that: " ... *a minimum time of approximately 8.5 minutes is available for the operator to perform the necessary switchover manual actions to ensure a continued suction source to the charging and safety injection pumps." The manual actions referred to in the statement above are the operator actions necessary to complete the semiautomatic switchover in modes 1 -3. Semiautomatic switchover is only required to be operable in modes 1 -3 in accordance with the Technical Specification Switchover from injection to recirculation for Mode 4 LOCA mitigation is performed manuall The 8.5 minute time referred to in the July 17, 1980 letter is associated with the amount of time available from the RWST low level setpoint to reaching the low-low level setpoint for a Large Break Loss of Coolant Accident (LBLOCA) . 95-4933
- .Document Control Desk LR-N970293 3 * MAY 2 7 1997 The January 5, '1987 letter discusses that the amount of time for manual switchover during a Mode 4 LOCA is approximately 18.5 minutes. Since the switchover in Mode 4 is a complete manual switchover, the 18.5 minute switchover time referred to in the January 5, 1987 letter is not relevant to the time discussed in statement 1 of the Amendment 69 SER. Therefore, PSE&G proposes that statement 1 of the Amendment 69 SER needs to be corrected to reflect the minimum time that was stated in PSE&G's July 17, 1980 submittal as follows: Revised Statement 1: " ... approximately 8.5 minutes (for a large break LOCA) would be available for the operator to perform the necessary switchover manual action ... " Discussion of SER Statements 2 and 3: To support the NRC's review of Amendment 69, PSE&G submitted the proposed changes to the Salem Unit 2 Emergency Operating Procedure, EOP-LOCA-3, required to implement the semiautomatic switchover modification on January 3, 1986 (Reference 5 of the Amendment 69 SER) . The revisions to EOP-LOCA-3, "Transfer to Cold Leg Recirculation," included the addition of a step to ARM the 21 and 22SJ44 valves (sump isolation valves) for semiautomatic switchover following the verification that the containment sump level had reached an appropriate level to support adequate net-positive suction head (NPSH) for the residual heat removal (RHR) pumps. The verification of sump level was to confirm that the water inventory contained in the sump was sufficient to support RHR pump operatio This step would prevent the operator from opening the sump isolation valves in the unlikely event that water loss outside containment could impair suction to the RHR pumps. The condition for entering LOCA-3 is the receipt of the low level alarm in the RWST. Based on the information provided by PSE&G in the January 3, 1986 letter, statements 2 and 3 (identified above) in the Amendment 69 SER do not correctly characterize the procedure changes sent to the NRC. PSE&G proposes that the above statements in the Amendment 69 SER should be changed as follows: 95-4933
- Document Control Desk LR-N970293 Revised Statement 2: * 4 MAY 2 7 1997 "EOP-LOCA-3 is entered upon receipt of the RWST low level alarm. One of the very early steps in EOP-LOCA-3 is to arm the SJ44 valves upon verification of containment sump level for initiation of* semiautomatic switchover." Revised Statement 3: "The operator is instructed by the emergency procedure to monitor the containment sump water level and verify that the appropriate sump water level has been reached prior to arming the containment sump isolation valves." The above changes to the Amendment 69 SER will ensure that the SER accurately reflects the information provided to the NRC by PSE&G to support the review of TS Amendment 69. RWST Drain Down Re-Evaluation On May 15, 1997, a re-evaluation of the Unit 2 RWST drain down evaluation was completed by Westinghouse and approved for use by a PSE&G safety evaluation on May 20, 1997. The re-evaluation of the drain down analysis was performed to eliminate the reliance on a period of interrupted ECCS pump flow during the performance of switchover from the injection mode to the recirculation mode of operation following a LOCA. The interruption of ECCS pump flow was introduced into the Salem licensing basis during a safety evaluation performed in March 1996. The introduction of the interruption of ECCS pump flow during switchover was determined to be inconsistent with the NRC's approval of the installation of the semiautomatic switchover feature as documented in the Amendment 69 SER. The Amendment 69 SER states, " ... The automatic actions of the switchover system are designed to provide an uninterrupted flow of ECCS water to the core." As discussed in the May 20, 1997 safety evaluation, the new RWST drain down evaluation determines that the worst case minimum time available for the switchover, based on the most limiting single equipment failure, is associated with a Safety Injection Accumulator Line Small Break LOCA (SBLOCA) . Since the Reactor Coolant System (RCS)
remains above the shutoff head of the RHR pumps during the Accumulator Line SBLOCA, the RHR pumps do not provide any direct flow into the RCS. The flow into the RCS during the Accumulator Line SBLOCA is provided by the High Head Safety Injection (HHSI) pumps and the Intermediate Head Safety Injection (IHSI) pumps. To continuous flow from the ECCS pumps to the RCS during an Accumulator Line SBLOCA, the 95-4933
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- 5 MAY 2 7 1997 HHSI and IHSI pump suctions have to be aligned to the discharge of the RHR pumps prior to reaching the low-low level setpoint in the RWST. For a LBLOCA, the pressure in the RCS drops below the shutoff head of the RHR pumps so that the RHR pumps are providing flow to the core. Since the semiautomatic switchover logic ensures continuous suction to the RHR pumps during the switchover (by aligning the RHR pumps to the containment sump prior to closing the RWST to RHR pump isolation valves), there is no interruption of RHR pump flow to the RCS during a LBLOCA. At the point in the EOPs when the containment sump isolation valves are open, there is sufficient NPSH available from the containment sump to provide suction to the RHR pumps. The flow delivered by one RHR pump is sufficient to meet the long term core cooling requirements of the analysis of record. Therefore, the HHSI or IHSI pumps may be stopped without interrupting ECCS pump flow to the core. The switchover during a LBLOCA is considered complete when the RHR pump suction is transferred from the RWST to the containment sump. In the case of the Accumulator Line SBLOCA, the May 15, 1997 drain down evaluation calculates that from receipt of the RWST low level alarm until reaching the RWST low-low level setpoint, there are 11.2 minutes available to complete the switchove This 11.2 minute time is based on meeting two critical steps in EOP-LOCA- The first critical step is to initiate closure of the SJ69 valve (common suction valve from the RWST to the RHR pumps) within 3 minutes, and the second critical step is to stop one of the Containment Spray pumps within 5.5 minutes of receipt of the. RWST low level alarm. To ensure successful completion of the switchover, the operators are being trained to ensure that they meet the critical steps in the EOP within the required time and that they complete the switchover within 11.2 minutes to ensure no interruption of ECCS pump flow to the RCS. The May 15, 1997 drain down evaluation also calculated that the time available for completion of switchover for a LBLOCA is 9.5 minutes which is consistent with the value provided to the NRC in the July 17, 1980 submitta During a LBLOCA, the RHR pumps do not lose suction during the switchover and are continuously providing flow to the core. However, in the case of the Accumulator Line SBLOCA, ECCS pump flow to the core could be interrupted if the switchover is not completed within the 11.2 minutes calculated in the new drain down evaluatio Since the possibility of interruption of ECCS pump flow does not exist for the LBLOCA but exists for the case of the Accumulator Line SBLOCA, the time associated with the 95-4933
- Document Control Desk LR-N970293 6 * MAY 2 7 1997 .. Accumulator
.,Line SBLOCA *becomes the most limiting time for training of the operator ECCS Pump Operation During Switchover In PSE&G's submittals on July 17, 1980 titled, "Proposed Conceptual Design ECCS Automatic Switchover," and the January 27, 1983 submittal titled, "Request for Amendment to Facility Operating Licenses DPR-70 and DPR-75 (LCR 82-16)", PSE&G stated that one of the functional features of the semiautomatic switchover was that: "Flow is uninterrupted from all ECCS pumps during switchover." In these same submittals, PSE&G defined that Design Criteria for the ECCS switchover modifications include (among other criteria):
- "The minimum flow entering the reactor coolant system during and after the switchover shall be sufficient to remove fission product decay heat assuming any single active failure." * "The switchover of the ECCS from the injection to the recirculation mode of operation shall be automated to the maximum feasible extent, such that required operator actions are minimized, and uninterrupted ECCS flow is provided to the core." As stated previously, PSE&G defines that in the case of the LBLOCA, that the switchover is complete upon transfer of the RHR pump suction from the RWST to the containment sump. Since the RHR pumps provide sufficient flow to the core to meet long term core cooling requirements during the LBLOCA, this definition for completion of the switchover is consistent with the design criteria of the semiautomatic switchove In the case of the Accumulator Line SBLOCA, the switchover is defined as being completed when the HHSI and IHSI pump suctions have been aligned to the discharge of the RHR pumps. Since the RHR pumps are not supplying flow to the core in the Accumulator Line SBLOCA, the HHSI and IHSI pumps are necessary to supply sufficient core flow to meet long term core cooling requirement In the approval of Amendment 69, the NRC states in the SER that, " ... The automatic actions of the switchover system are designed to provide an uninterrupted flow of ECCS water to the core." The definition of completion of the switchover as stated above meets the design requirements contained in the July 17, 1980 and 95-4933
.. * . Document Control Desk LR-N970293 7 * MAY 2 7 1997 January 27, 1983 *submittals, and the Amendment 69 SER. Based upon meeting these design requirements and our current review of the switchover process, PSE&G is clarifying the discussion of the swtichover process as described within these submittals as follows: Original Statement: "Flow is uninterrupted from all ECCS pumps during switchover." Revised Statement: "Flow is uninterrupted from the ECCS pumps required to meet long term core cooling requirements during the switchover." Operator Omission and Commission In the July 17, 1980 submittal titled, "Proposed Conceptual Design ECCS Automatic Switchover," and the January 27, 1983 submittal title, "Request for Amendment to Facility Operating Licenses DPR-70 and DPR-75 (LCR 82-16)", PSE&G informed the NRC that semiautomatic switchover would include the following feature: "The manual actions can tolerate any postulated single failure without preventing transfer to recirculatio This includes an operator error single failure which results in (a) the failure to perform one step, or (b) the performance of one step out of sequence." As a result of this statement, a review of the development of the Emergency Operating Procedures (EOPs) was performed considering operator omission or commission (failing to perform a step or performing a step out of sequence) . The EOPs were developed based upon the guidance provided by the Westinghouse Owners Group Emergency Response Guidelines (ERG) . The ERG program was developed based on the requirements of NUREG-0737, Item I.C.1, "Guidance for the Evaluation and Development of Procedures for Transients and Accidents." NUREG-0737, Item I.C.1, defines operator errors of omission or commission as an example of a multiple failure event. Since the time calculated in the RWST drain down analysis is based upon the worst case single failure, consideration of operator omission and commission (multiple failure) in the operator training to meet this calculated time is not warrante * Document Control Desk LR-N970293 8 * MAY 2 7 1997 * In the unlikely event that an operator fails to perform, or improperly performs a critical step in the EOP, which results in inadequate core cooling, the operator would be directed to a functional restoration procedur Functional restoration procedures are designed to address multiple failure events. In addition, failure of an operator to perform a step in the EOP is highly unlikely based on the following:
- Operators receive frequent training on the performance of LOCA-3. * EOP-LOCA-3 has been human factored to minimize the time required to reach critical steps {a critical step is a step with a time requirement provided in the RWST drain down analysis).
- Three point communications by the operating crews minimizes the potential for mis-communication that would be experienced during implementation of the EOPs. Consistent with the industry guidance for the development of the EOPs, inclusion of operator omission and commission in the RWST drain down and operator training, to ensure switchover is completed within the times stated in the drain down evaluation, is not considered to be necessar Therefore, PSE&G's commitment as stated in the July 17, 1980, and January 23, 1983, letters is being revised to state: "The manual actions can toierate any postulated single failure without preventing the transfer to recirculation." If you have any questions regarding this submittal please contact us. &5-4933
... ... Document Control Desk LR-N970293
- 9 C Mr. H. J. Miller, Administrator-Region I U. S. Nuclear Regulatory Commission 475 Allendale Road King of Prussia, PA 19406 Mr. L. Olshan, Licensing Project Manager -Salem U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail 'Stop 14E21 Rockville, MD 20852 Mr. C. Marschall (X24) USNRC Senior Resident Inspector-Salem Mr. K. Tosch, Manager IV Bureau of Nuclear Engineering 33 Arctic Parkway CN 415 Trenton, NJ 08625 MAY 2 7 1997 95-4933