ML18066A265
| ML18066A265 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 08/03/1998 |
| From: | Haskell N CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-97-04, GL-97-4, NUDOCS 9808110080 | |
| Download: ML18066A265 (11) | |
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I A CMS Energy Company August 3, 1998 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Palisades Nuclear Plant Tel: 616 764 2276 27780 Blue Star Memorial Highway Fax: 616 764 2490 Covert. Ml 49043 Nathan L. Hasllall Director. Licensing DOCKET 50-255 - LICENSE DPR PALISADES PLANT RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING GL 97-04, AND CORRECTION OF ERRORS IN ORIGINAL RESPONSE TO GL 97-04 Generic Letter (GL) 97-04, "Assurance of Sufficient Net Positive Suction Head for Emergency.Core Cooling and Containment Heat Removal Pumps", issued October 7, 1997, requested that licensees provide certai11 information for their facilities.
Consumers Energy Company responded on January 5, 1998, providing the requested information for the Palisades Plant. On July 2, 1998, the NRC issued a request for additional information (RAI) related to our response. Attachment 1 provides fhe additional information.
During preparation of the Consumers Energy Company response to the RAI, we discovered errors in our original response to GL 97-04. The errors occurred during translation of data from the NPSH calculation into our original GL 97-04 response. The corrected information is provided in Attachment 2.
During an NRC Region Ill Engineering & Technical Support (E&TS) Inspection conducted at Palisades during the weeks of July 6 and July 20, 1998, the NRC inspection team questioned the pump manufacturers' confirmations of the capability of the High Pressure Safety Injection (HPSI) and Containment Spray (CS) Pumps to operate during short-term periods when available NPSH is less than required.
Documentation of the confirmations, on file at Palisades upon E& TS inspection team arrival, was not considered by the team to be sufficient to conclude that the manufacturers had enough information to render a conclusive judgement regarding pump operation.
9808110080 980803 PDR ADOCK 05000255 P
PDR l
2 In response to the E&TS Inspection team's concern, additional discussions were held with the pump manufacturers and specific pump operating conditions were described.
At our request, the manufacturers forwarded additional documentation to Consumers Energy confirming that the pumps would continue to operate and deliver flow for several minutes until required NPSH is met through proceduralized operator actions.
SUMMARY
OF COMMITMENTS This letter contains no new commitments and no revisions to existing commitments.
irector, Licensing CC Administrator, Region Ill, USNRC Project Manager, NRR, USNRC NRC Resident Inspector - Palisades 2 Attachments
CONSUMERS ENERGY COMPANY To the best of my knowledge, the contents of this letter are truthful and complete.
By Sworn and subscribed to before me this 3~ day of~
1998.
~~~~
Alora M. Davis, Notary Public Berrien County, Michigan (Acting in Van Buren County, Michigan)
My commission expires August 26, 1999
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ATTACHMENT 1 CONSUMERS ENERGY COMPANY PALISADES PLANT DOCKET 50-255 RESPONSE TO NRC REQUEST FOR ADPITIONAL INFORMATION REGARDING GL 97-04 2 Pages
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RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING GL 97-04 NRC REQUESTED INFORMATION (1)
In response to question 1, it is stated that 'Yhe containment water level, which determines h51, is conservatively assumed to be less than the predicted minimum water level following a large break LOCA." What is the predicted minimum water level, e.g., the containment floor or an amount above the containment floor?
CONSUMERS ENERGY RESPONSE (1)
The predicted minimum water level is an amount above the containment floor.
The minimum predicted level is at elevation 593.5 feet (i.e. 3.5 feet above the containment floor). The minimum water level assumed in the NPSH calculation is 593 feet (i.e. 3 feet above the containment floor).
NRC REQUESTED INFORMATION (2)
What is the maximum sump temperature assumed in the NPSH analyses? Is subcooling credited?
CONSUMERS ENERGY RESPONSE (2)
The NPSH analysis assumes a sump water temperature of 211.9°F. Subcooling of the sump water is not credited.
NRC REQUESTED INFORMATION (3)
Jn response to question 2, eight cases are evaluated. In Case 1, "Left Channel Failure of Safety Injection," the NPSH available is less than the NPSH required fOr a small amount of time. Why isn't this the design case for Palisades?
CONSUMERS ENERGY RESPONSE (3)
The Engineered Safeguards System (ESS) NPSH analysis used the term "design case" to refer to those ESS lineups that persist for long periods of time following a design basis accident. Case 1 in the initial response to Generic Letter 97-04 is a short-term transient state (-10 minutes) that occurs prior to establishing the long-term system lineup. For this reason, it was not termed a design case. Palisades' initial response to GL 97-04 was based on this terminology. Short-term operation in the Case 1 lineup is approved by the HPSI and Containment Spray pump vendors. In the other lineups, sufficient NPSH. is available to assure long-term pump operability.
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RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING GL 97-04 NRC REQUESTED INFORMATION (4)
In response to question 3, it is stated that the current NPSH analyses were completed in November 1996 under 10 CFR 50. 59. Discuss the changes made to the analyses between the current NPSH analyses and the previous NPSH analyses.
CONSUMERS ENERGY RESPONSE (4)
The original Safety Evaluation Report dated March 6, 1970, received from the Atomic Energy Commission (AEC), concludes that the ECCS will perform its functions as designed. Palisades has not located any subsequent NRC Safety Evaluation Report that supersedes the original SER in this respect.
Palisades is unable to locate the calculations that may have been reviewed by the AEC or that generated the information in the original FSAR. Because of this status, the current November 1996 NPSH analysis is considered to be a reconstitution of the original calculations. The current analysis was performed to generate recirculation mode flow rates and pressures, verify EOP guidance and decision criteria, and include the effects of pump testing uncertainty and acceptance criteria in the system analysis. The current analysis is considered to have superseded previous NPSH and related system calculations.
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ATTACHMENT 2 CONSUMERS ENERGY COMPANY PALISADES PLANT DOCKET 50-255 CORRECTION OF ERRORS IN CONSUMERS ENERGY RESPONSE TO GL 97-04 DATED JANUARY 5, 1998 4 Pages
CORRECTION OF ERRORS IN CONSUMERS ENERGY RESPONSE TO GL 97-04 DATED JANUARY 5, 1998 During preparation of the Consumers Energy Company response to the request for additional information, errors were noted in our original response to GL 97-04. The errors occurred during translation of data from the NPSH calculation into our original GL 97-04 response. These errors have been corrected as described below. All of the errors occurred within our response to the NRC Requested Information (2) from GL 97-04, which stated, "Identify the required NPSH and the available NPSH for each pump."
Due to a transcription error in extracting data from the NPSH calculation for the original response, an incorrect NPSHA value was listed for pump P-66A in the discussion of Case 1. The revised Case 1 response is as follows:
(Case 1) Left Channel Failure of Safety Injection Operation of CS Pump P-54A, HPSI Pump P-66A, & 2 Spray Headers just after the initiation of recirculation.
Pump Flow Rate, gpm NPSHA, ft NPSHR, ft CS Pump P-54A 2400
<19.5 21.0 HPSI Pump P-66A 695
<17.7 20.8 The available NPSH is listed as less than 19.5 feet for the spray pump and less than 17.7 feet for the HPSI pump because the case used for this data assumed a containment water elevation of 595 feet. Using the minimum acceptable water elevation of 593 feet, the available NPSH would be approximately 17.5 feet for the spray pump and 15. 7 feet for the HPSI pump.
This mode of operation exists from the time of suction switchover until the operators place the subcooling lineup in service (i.e., several minutes). The CS and HPSI pump manufacturers have approved operation of the pumps in this mode for the required period of time.
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CORRECTION OF ERRORS IN CONSUMERS ENERGY RESPONSE TO GL 97-04 DATED JANUARY 5, 1998 Due to a transcription error in extracting data from the NPSH calculation, an incorrect NPSHR value was listed for pump P-54C in the discussion of Case 5. Additionally, Case 5 conservatively assumed a containment water level of 592 feet. This is one foot lower than the minimum required containment water level of 593 feet. As a result, the NPSHA values listed for the three pumps in the original Generic Letter 97-04 response were also low by one foot. The NPSHA values for the three pumps are corrected in the table below to show the additional 1 foot of available NPSH. The revised Case 5 response is as follows:
(Case 5) Right Channel Failure of Safety Injection Operation of CS Pumps P-548 & P-54C, HPSI Pump P-668, & 2 Spray Headers just after the initiation of recirculation.
Pump Flow Rate, NPSHA, ft NPSHR, ft gpm CS Pump P-548 1686 18.9 13.2 CS Pump P-54C 1629 18.9 13.4 HPSI Pump P-668 688 18.0 21.6 This is the lineup immediately after RAS (the recirculation actuation signal),
before the operators take manual action to open the subcooling valve for the HPSI pump. This lineup would be in service for only a few minutes. The HPSI pump manufacturer has approved operation of the pump in this mode for the required period of time.
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CORRECTION OF ERRORS IN CONSUMERS ENERGY RESPONSE TO GL 97-04 DATED JANUARY 5, 1998 Case 6 also assumed a containment water level of 592 feet instead of the minimum allowable water level of 593 feet. As with Case 5, this assumption reduced the available NPSH listed in the NPSH calculation for each pump by one foot. The revised Case 6 response corrects the NPSHA values to a containment water level of 593 feet.
(Case 6) Right Channel Failure of Safety Injection Operation of CS Pumps P-548 & P-54C, HPSI Pump P-668, & 2 Spray Headers, subcooling in service.
Pump Flow Rate, NPSHA, ft NPSHR, ft gpm CS Pump P-548 1914 18.7 14.7 CS Pump P-54C 1855 18.7 14.7 HPSI Pump P-668 722 360.0 23.6 This is the design case for Palisades. This is the lineup established after the operators take manual action to open the subcooling valve to the HPSI pump.
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CORRECTION OF ERRORS IN CONSUMERS ENERGY RESPONSE TO G~ 97-04 DATED JANUARY 5, 1998 Due to a transcription error in extracting the data from the NPSH calculation, incorrect flow rates were provided for the two spray pumps and the HPSI pump in Case 8.
Additionally, Case 8 also assumed a containment water level of 592 feet. The revised response below corrects the pump flow rates and incorporates the additional 1 foot of available NPSH.
(Case 8) Right Channel Failure of Safety Injection Operation of CS Pumps P-548 & P-54C, HPSI Pump P-668, 2 Spray Headers, subcooling in service, LPSI (Low Pressure Safety Injection) Pump P-678 in service for Primary Coolant System (PCS) sampling.
This case analyzes the lineup when a LPSI pump is used to sample the PCS/Containment water. The LPSI pump flow rate is limited to 2000.gpm.
Pump Flow Rate, NPSHA, ft NPSHR, ft gpm CS Pump P-548 1913 18.4 14.7 CS Pump P-54C 1854 18.3 14>>6 HPSI Pump P-668 721 359.8 23.6 LPSI Pump P-678 2000 18.4
<10-12 ft.
estimated The NPSHR for the LPSI pump is estimated because a flow rate of 2000 gpm is less than the lowest flow rate on the manufacturer's NPSHR curve.
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