ML20050A950
| ML20050A950 | |
| Person / Time | |
|---|---|
| Site: | La Crosse File:Dairyland Power Cooperative icon.png |
| Issue date: | 03/29/1982 |
| From: | Taylor J DAIRYLAND POWER COOPERATIVE |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| References | |
| PGO-92, NUDOCS 8204020433 | |
| Download: ML20050A950 (2) | |
Text
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D DA/RYLAND
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[k COOPERAT/VE eO box 817
- 2615 EAST AV SOUTH LA CROSSE. WISCONSIN M601 (608) 788-4000 JAMES TAYLOn March 29, 1982 Assistant GenerM Manager Power croup Ref:
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Mr. Dennis M. Crutchfield, Chief Operating Reactors Branch #5
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Washington, D.C.
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Subject:
Risk Assessment Program - La Crosse Boiling Water Reactor
Dear Mr. Crutchfield:
Following the meeting with Dr. Harold Denton on February 22 at which time we discussed a short form risk assessment of LACBWR, we engaged Saul Levine of NUS and Norman Rasmussen of MIT to make this assessment. On February 28, a conference call was held among Denton, Rasmussen, Levine and Shimshak to discuss the general aspects of conducting a simplified risk assessment for LACBWR.
Following this phone conversation, NUS mobilized a small investigative team which came to the plant site to make preliminary investigations, collect data and formulate the approach for this evaluation.
On March 22, Dr. Rasmussen and Levine came to La Crosse to visit the plant and discuss the approach to the simplified risk assessment.
Rasmussen and Levine arrived at the facility shortly after 8:00 a.m.
and sper' much of the morning discussing plant systems with the plant super-visory and engineering staff.
Later in the morning, we conducted a tour of the entire facility including inside of containment, and returned to complete the discussion during the early afternoon. We reached certain conclusions with regard to the approach to the simplified risk assessment program.
NUS will prepare event trees analyzing the probability of the contri-bution to a core accident by each of the systems identifiable within the plant. A numerical probability will be assigned to each of the contributors based upon (1) the evaluator's experience and knowledge of nuclear reactors applicable to the specifics of the LACBWR systems; (2) an analysis of previous work done by others in evaluating these systems together with recommendations of others for improvements to these systems to minimize the probability of failure and (3) the operating experience on the reactor systems to date and the reported failures or anomalies recorded on each.
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PDR ADOCK 05000409 P
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Mr. Dennis M. Crutchfield, Chief Page 2 March 29, 1982 I
i The report to be prepared for our review on April 15 will quantitatively 1
evaluate the plant systems and will recommend which systems have the lowest probability to failure as well as those which have the highest probability to failure.
Supporting statements will be provided for each determination. Those systems which are questionable will likely be recommended for further evaluation; those systems which have a high probability of failure will be studied further to
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determine what modifications are needed to reduce the probability to an acceptable level.
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The report to be prepared by April 15 will, of necessity, be brief since there is neither time nor intent to do a full-blown probabilistic risk assess-a ment at this time. However, based upon the experience level of the evaluators, it is assumed that this report will have significant bearing on the need for further evaluation of specific systems and should, indeed, give ample support
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j for climinating others from further concern.
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l In view of the small size of this reactor plant, it might be compared to those used to power submarines and/or surface vessels in the United States Navy and, in mar,y respects, might well be treated in the same category. We are con-l l
fident that this analysis will reveal many areas that can be removed from further concern and identify only those systems for which additional work is needed. Only l
1 if we can reduce the financial burden imposed by complete and detailed analysis of every system and component in this facility will we be able to continue oper-ating as a power production facility.
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f We look forward to meeting with you next and to presenting the findings of i
HUS.
L Sincerely,
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cc:
Frank Linder Dick Shimshak f
Ernie Tremmel t
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