NPL-98-0895, Discusses Part Length CRDM Housing Issue at Plant
| ML20155C350 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 10/23/1998 |
| From: | Reddemann M WISCONSIN ELECTRIC POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NPL-98-0895, NPL-98-895, NUDOCS 9811020205 | |
| Download: ML20155C350 (2) | |
Text
1 MARK E. REDDEMANN l Wisconson Electnc A WISCONSIN ENERGY COMPANY Point Beach Nuclear Plant 6610 Nuclear Rd.
Two Rivers, WI 54241 Phone 920 755-6527 NPL 98-0895 October 23,1998 Document Control Desk U.S. NUCLEAR REGULATORY COMMISSION Mail Station Pl-137 Washington, DC 20555 Ladies / Gentlemen:
DOCKETS 50-266 AND 50-301 PART LENGTH CRDM HOUSING ISSUE POINT BEACH NUCLEAR PLANT. UNIT 1 AND 2 In a letter to the NRC dated March 23,1998, Wisconsin Electric Power Company discussed its plans for addressing the part length control rod drive mechanism (PLCRDM) housing issue at the Point Beach Nuclear Plant (PBNP). In that letter, we committed to remove the PBNP Unit 1 PLCRDM housings during the unit's spring 1998 refueling outage which had commenced on February 27,1998. During the outage, the housings were removed and the reactor head penetrations capped. PBNP Unit I completed its refueling outage on Jun'e 30,1998, and has been returned to power operation.
At the time of the March 23 letter, our plans for addressing this issue for PBNP Unit 2 were not established. We anticipated that the other affected Westinghouse Owners Group (WOG) utilities would fonn a WOG Part Length Control Rod Drive Mechanism (PLCRDM) Subgroup to develop the details of an integrated plan to address this issue. That plan included reviews of the information from inspections and evaluations conducted by the other WOG affected member utilities, the information from a PLCRDM fabrication records review conducted by Westinghouse, and the results of a risk assessment. We expected that our specific plans to address the PLCRDM housing issue for Unit 2 would be based upon the results of the inspection of the PLCRDM housings removed from Unit I and the information developed from these WOG PLCRDM activities.
On October 15,1998, the WOG transmitted to the NRC copies of WCAP-15126, " Technical 1
Assessment of the Part Length CRDM Housing Motor Tube Cracking in Westinghouse Owners j
Group Plants," dated October 1998. This report contains the results of the issue investigation O.
conducted by the WOG PLCRDM Subgroup. Included in that report are the results of the examination of the PLCRDM housings removed from Point Beach Unit I and another WOG plant. No evidence ofhousing weld flaws similar to that found at the Prairie Island ' Unit 2 0\\
9 l
facility were identified in any of the removed PLCRDM housings or in any of the weld inspections in the field.
o 9811020205 981023 PDR ADOCK 05000266 P
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' I NPL 98-0895 10/23/98 Page 2 The information presented in WCAP-15126 is consistent with the preliminary evaluation information which has been discussed with the NRC staff during a number of public meetings, including the most recent meeting on October 5,1998 We believe this report presents a complete response to the concerns identified during this investigation and will enable closure of the PLCRDM issue.
Based on the information and conclusions presented in WCAP-15126, which includes the results of the inspection of the Unit 1 PLCRDM housings, we have concluded that additional efforts to either NDE inspect or remove the PLCRDMs from the PBNP Unit 2 reactor vessel head are not warranted. The evidence presented in WCAP-15126 concludes that the flaw observed in the Prairie Island PLCRDM was an isolated event and manufacturing related. Continued operation of those plants which have not removed or inspected the PLCRDM housings will not result in a significant increase in risk.
The conclusions in WCAP-15126 also support the return to normal reactor coolant system leakage monitoring due to the very low probability for the occurrence of PLCRDM leakage and the effectiveness of normal leakage monitoring. These mecsures had been instituted to increase reactor coolant system leakage monitoring awareness while the in-depth investigation of the Prairie Island PLCRDM issue was completed. Presently, the compensatory actions discussed in our March 23 letter are still in effect. However, we no longer consider these measures to be commitments and reserve the prerogative to teturn to the leakage.nonitoring measures in place prior to this issue.
Please contact us with any questions you may have concerning our plans in this matter.
Sincerely,
/MKu W e.
Mark Reddemann Site Vice President Point Beach Nuclear Plant CWK/dms cc:
NRC Resident inspector NRC Regional Administrator NRR NRC Project Manager PSCW