ML20079F646
| ML20079F646 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 06/02/1982 |
| From: | Mardis D FLORIDA POWER CORP. |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| 3F-0682-02, 3F-682-2, NUDOCS 8206080121 | |
| Download: ML20079F646 (2) | |
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RQf Florida Power C O m r O n a Y e o es June 2,1982
- 3F-0632-02 File: 3-B-6 Mr. John F. Stolz, Chief Operating Reactor Branch #4 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D.C. 20555
Subject:
Crystal River Unit 3 Docket No. 50-302 Operating License No. DPR-72 Safe-End Task Force Action Plan
Dear Mr. Stolz:
Florida Power Corporation shut down Crystal River Unit 3 in late January 1982 dae to a primary coolant leak. The cause of the leak was determined to be a crack in the safe-end weld of the normal duty makeup /high pressure injection (MU/HPI) check valve. Further investigation also revealed extensive cracking in the safe-end just downstream of the check valve. No cracks were found in the nozzle. Subsequent inspections by other utilities operating Babcock and Wilcox (B&W) Nuclear Steam Supply Systems of similar design have revealed similar problems. This correpondence details the status of actions on this issue.
In response to an NRC request on March 8,1982, the C&W Regulatory Response Group (RRG) met with NRC to discuss continued operation of B&W plants that had not yet been inspected for similar problems (all except Crystal River Unit 3, and Oconee Units 2 and 3). The RRG met again with the NRC on March 16, 1982, at which time all non-inspected plant owners committed to inspect in the near future.
At the same time, the B&W Owners Group Executive Committee established a Safe-End Task Force for the purpose of determining the cause of the MU/HPl safe-end and thermal shield cracking and to make recommendations for implementing a solution to the problem. The Task Force met on March 25-26,1982, to organize and develop an Action Plan. By early April,1982, the Task Force had authorized B&W to begin collecting pertinent data, reviewing industry experiences, evaluating additional instrumentation, etc. The Task Force met again on April 27,1932, to review the data B&W had collected and revise the Action Plan. A final three phase Action Plan was subsequently developed. On May 7,1982, the Task Force met with the NRC to discuss the status of the investigation and present the new Action Plan The Task Force Action Plan, as presented to you on May 7,1982, is delineated below, g[
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pop General Office 3201 inirty.tourin street souin. P O Box 14042. St Petersburg, Florida 33733 813-866-5151
s Mr. John F. Stolz June 2,1982 Page 2 Phase 1 of the Action Plan consisted of compiling the facts possibly relevent to the failures, evaluating the data from instrumentation that had been installed at Crystal River Unit 3, determining testing alternatives, and continuing component failure analyses.
Additionally, a review of industry experience and an evaluation of the need and feasibility of additional instrumentation was conducted. The goal of Phase I was to allow a concise evaluation of the facts and develop some possible hypotheses which would account for the facts.
Phase 2 consists of actual determination of a most likely cause and identification of how this cause is supported by the information available from Phase 1. This phase will then determine to what extent additional analyses or testing is required to conclusively support the most likely cause identified.
Phase 3 begins when the Safe-End Task Force is convinced that the cause of the failures has been adequately determined, and no further supportive work is required. The result of Phase 3 is a final statement of cause, and a recommendation for implementation of design or operational changes to preclude further failures. As a part of these recommendations, the Task Force will also address the need for additional inservice inspections until the recommended changes are made.
Both the safe-end cracking of the double duty lines and the loose thermal sleeves found in HPI lines will be investigated by this Task Force.
Consideration of the generic applicability of these problems to other thermally sleeved nozzles will be given.
As of mid-May,1982, the Task Force is actively pursuing Phase 2 activities. The schedule for completion of this Action Plan is by the end of 1982. The rask Force will keep the NRC informed of the status of activities via routine site and regional communications methods.
Very truly yours,
.T 0
h David G. Mardis Acting Manager Nuclear Licensing KFP:mm cc Mr. 3. P. O'Reilly, Regional Administrator Office of Inspection & Enforcement U.S. Nuclear Regulatory Commission 101 Marietta Street N.W., Suite 3100 Atlanta, GA 30303
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