ML053490051
| ML053490051 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 12/15/2005 |
| From: | Harden P Nuclear Management Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| BL-03-001 | |
| Download: ML053490051 (4) | |
Text
Committed to Palisades Nuclear Plant Operated by Nuclear Management Company, LLC December 15,2005 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Palisades Nuclear Power Plant Dockets 50-255 License No. DPR-20 Revision of Commitment from Supplement to Bulletin 2003-01, "Potential Impact of Debris Blockaqe on Emerqencv Sump Recirculation at Pressurized-Water Reactors" On June 9, 2003, the Nuclear Regulatory Commission (NRC) issued Bulletin (BL) 2003-01. By letter dated August 5,2003, Nuclear Management Company, LLC (NMC) provided the 60-day response for the Palisades Nuclear Plant (PNP).
By letter dated May 17, 2004, NMC submitted a supplement to the Bulletin response for PNP that addressed the candidate operator actions (COAs), as described in the Westinghouse Owners Group (WOG) WCAP-16204, "Evaluation of Potential ERG and EPG Changes to Address NRC Bulletin 2003-01 Recommendations," Revision I. In the supplement, several commitments were made. Specifically, NMC committed to the following:
- 2. NMC will implement the following candidate operator actions by December 15, 2005, at the Palisades Nuclear Plant.
COA # I Secure one containment spray pump before recirculation alignment COA #3 Terminate one train of high pressure safety injectionlhigh-head injection after recirculation alignment The implementation date of December 15, 2005, is contingent upon the need for prior NRC approval for any design or licensing basis changes. If prior NRC approval is required, the implementation date will be revised accordingly.
NMC has subsequently determined that COA #3 cannot be implemented at PNP.
Therefore, NMC is deleting the commitment to implement COA #3. Enclosure 1 provides the basis for the commitment revision. NMC remains committed to implement COA #I, at PNP, by December 15, 2005. NMC believes this, together with the compensatory measures already in place at PNP, are adequate to address the issue raised in BL 2003-01.
27780 Blue Star Memorial Highway o Covert, Michigan 49043-9530 Telephone: 269.764.2000
Document Control Desk Page 2 Summary of Commitments This letter contains no new commitments and one revision to existing commitments:
Commitment made by letter dated May 17, 2004:
- 2. NMC will implement the following candidate operator actions by December 15, 2005, at the Palisades Nuclear Plant.
COA #I Secure one containment spray pump before recirculation alignment COA #3 Terminate one train of high pressure safety injectionlhigh-head injection after recirculation alignment The implementation date of December 15, 2005, is contingent upon the need for prior NRC approval for any design or licensing basis changes. If prior NRC approval is required, the implementation date will be revised accordingly.
Revised commitment:
- 2. NMC will implement the following candidate operator action by December 15, 2005, at the Palisades Nuclear Plant.
COA # I Secure one containment spray pump before recirculation alignment Site Vice President, Palisades Nuclear Plant Nuclear Management Company, LLC Enclosure (1 )
CC Administrator, Region Ill, USNRC Project Manager, Palisades, USNRC Resident Inspector, Palisades, USNRC
ENCLOSURE *I REVISION OF COMMITMENT FROM SUPPLEMENT TO BULLETIN 2003-01, "POTENTIAL IMPACT OF DEBRIS BLOCWGE ON EMERGENCY SUMP RECIRCULATION AT PRESSURIZED-WATER REACTORS" By letter dated May 17, 2004, Nuclear Management Company, LLC (NMC) submitted a supplement to the 60-day response to Bulletin 2003-01. In the supplement, several commitments were made. One of these commitments was to implement candidate operator action (COA) COA #3, "Terminate One Train of HPSl after Recirculation Alignment," at Palisades Nuclear Plant (PNP). In the supplement, NMC discussed implementing COA #3 using the alternative method described in CEN-I 52, "Combustion Engineering Emergency Procedure Guidelines," Revision 5.3. On April 13, 2004, the WOG formally transmitted CEN-152, "Combustion Engineering Emergency Procedure Guidelines," Revision 5.3., based on WCAP-16204. CEN-152 provides guidelines on implementing Emergency Operating Procedure (EOP) changes. Palisades EOPs are based on CEN-152.
The alternative method of implementing COA #3 at PNP involves a strategy of throttling HPSl flow to meet decay heat removal requirements. This strategy would potentially lower recirculation flow through the sump by several thousand gallons per minute while leaving both operating HPSI pumps in service. After further evaluation, NMC determined that implementing COA #3 at PNP represents a reduction in plant safety.
The high pressure safety injection (HPSI) loop isolation motor operated valves (MOVs) are located below the maximum anticipated loss-of-coolant accident (LOCA) containment water level. Per Emergency Operating Procedures, the HPSl loop isolation MOVs are required to be opened fully and the power removed by opening the associated breakers to prevent spurious operation of the HPSI loop isolation MOVs.
This precludes operating the HPSI loop isolation MOVs for the purposes of throttling flow post HPSl recirculation. Therefore, implementing COA #3 using the alternative method described above cannot be implemented at PNP.
NMC, in consultation with the Westinghouse Owners Group (WOG), then considered implementing COA #3 directly, not utilizing the alternative method. After further evaluation, NMC determined that implementing this COA directly would represent a reduction in plant safety. The HPSl system includes two HPSI pumps, each discharging to a train, HPSl train 1 and HPSl train 2. One HPSl pump has sufficient capacity to make up the inventory lost due to boil off by decay heat at the start of recirculation.
However, since the deliberate manual securing of one HPSl pump is not considered a "failure," the consequences of a postulated failure of the running HPSl pump, subsequent to manually stopping one of two HPSl pumps, presents an adverse effect on plant safety. This would result in an interruption of HPSl flow until the operator could identify the failed condition and recover the failed condition by restarting the previously secured HPSl pump. NMC has estimated that a total of 15 minutes would be required to identify and recover the failed condition at PNP. The 15 minutes represents the time interval for one safety function status check to be performed in order for the operator to recognize the loss of injection flow and take the necessary corrective action to recover core cooling functionality. Manual operator actions are required to defeat and secure the automatic initiation function of the HPSl pump to be idled. Automatic actions to recover from a single active failure are thereby defeated, which then would require additional manual actions to restore the idled pump. This presents an unacceptable level of risk to PNP.
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NMC evaluated the two options described above to determine if COA #3 could be implemented at PNP. However, each option would result in an unacceptable decrease in plant safety. Therefore, NMC has revised commitment two, made by letter dated May 5, 2005, to delete COA #3. NMC believes the compensatory measures already in place, together with implementing COA #I, are adequate to address the issue raised in Bulletin 2003-01, "Potential Impact of Debris Blockage on Emergency Sump Recirculation at Pressurized-Water Reactors."
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