ML20039E844

Comments on Anl Draft Repts Re Formalized Risk Decisionmaking Processes.Important Safety Implications Could Bear on Any NRC Decision to Shut Down Multiple Unit Plants

ML20039E844
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	01/08/1982
From:	Murley T NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO)
To:	Bernero R NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES)
References
CON-FIN-A-2233 NUDOCS 8201110536
Download: ML20039E844 (2)

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MEMORANDUM FOR: Robert M. Bernero, Director k

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Division of Risk Analysis, RES

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FROM:

Thomas E. Murley, Director Regional Operations and Generic Requirements Staff

SUBJECT:

COMMENTS ON DRAFT REPORTS (FIN #A2223), FORMALIZED RISK DECISIONMAKING PROCESSES We have given a quick review to the set of ANI. d > aft reports you sent for cow:sent under your memo of December 17, 1981. On the basis of this quick review, we offer the following comments:

1.

Although the ANL reports are directed more toward estimating loss 4

of benefits fr3m a prolonged total shutdown of multiunit plants, there does exist certain cost information useful to the CRGR and staff in estimating cost implications of generic requirements should these necessitat? limited plant outages.

For example, it is useful to note that across the six multiunit stations, covered by ANL, production cost increases associated with an outage occurring over the next year or so would range roughly at about 0.1 to 0.2 million dollars per MWe-year of outage. Can this be taken as a good input estimate on the costs of such CRGR decisions? If not, what cost inputs would be recommended by ANL7 2.

We tried to sumarize and tabulate the principal results across the set of ANL reports for generic insights on loss of benefits due to plant shutdowns. Some of the data and results appeared to be missing or not consistently treated from one plant to anoth.r.

across the six plants. Sincri we experienced these difficulties,a similar effort by ANL might be fruitful to help firm up the principal results and to extract / highlight the generic information.

i 3.

We noted that the implications of plant shutdown on grid reliability varied widely (from negliothle to very serious) across the plants studied. This finding has important safety implications that could bear on any NRC decision to cause a multiple unit shutdown in a licensee's grid on discovery of a generic safety problem or the occurrence of an incident elsewhere in a similar unit. This aspect of ANL's decision analysis could be more thoroughly explored and perhaps usefully extended to more than the six multiunit plants studied. Consider, for example, questions on what would be the reliability implications of BWR shutdowns in the Comonwealth Edison grid rather than a shutdown of the Zion unD3.

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decision to shutdown these BWRs importantly increase the risk of l

station blackout for the Zion units? How might this decision be best balanced for the Commonwealth grid or others? Such matters l

appear to have relevance to NRC implementation schedules and to l

certain of the unr:. solved safety issues such as USI A-44 and A-45.

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We noted for at least one of the multiunit plants studied by ANL, that a limited outage could vary substantially in absolute dollar costs depending on when the outage was scheduled in the year.

For example, cost savings of perhaps 50 to 100 millfor dollars for a 3-month outage interval were claimed if the plant outage was to be scheduled during more favorable off-This type of information (on a per unit basis) peak load periods.

may also be quite pertinent to NRC decisions on implementation schedules. You may wish to ask ANL l

to develop additional data in this particular area.

Originni signed by l

Thomas E. MurleY Thomas E., Murley, Director Regional Operations and Generic Requirements Staff Distribution:

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