ML20212F885

Forwards Draft, Criteria to Evaluate Seabrook EPZ Sensitivity Study for Comparison to Bases in NUREG-0396

ML20212F885
Person / Time
Site:	Seabrook
Issue date:	09/22/1986
From:	Jordan E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE)
To:	Novak T Office of Nuclear Reactor Regulation
Shared Package
ML20212F876	List: ML20212F871 ML20212F885
References
FOIA-87-51, RTR-NUREG-0396, RTR-NUREG-0654, RTR-NUREG-396, RTR-NUREG-654 NUDOCS 8703050203
Download: ML20212F885 (3)

Text

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IEP 221988 MEMORANDUM FOR: Thomas M. Novak, Acting Director Division of PWR Licensing-A Office of Nuclear Reactor Regulation FROM: Edward L. Jordan. Director Division of Emergency Preparedness and Engineering Response Office of Inspection and Enforcement SU5 JECT: CRITERIA TO EVALUATE SEABROOK EPZ SENSITIVITY STUDY Enclosed is a draft of technical criteria for comparison to the bases in NUREG-0396 to be used in the evaluation of the Seabrook EPZ Sensitivity Study. The criteria were developed following a meeting on September 3,1986, between ten Soffer and Steve Long, NRR, and Dave Matthews and Don Perrotti, IE. As agreed upon at the meeting, Len Soffer took the lead in drafting the criteria. IE has determined that the enclosed draft criteria (with the minor modification noted on page 2) are appropriate for use in the evaluation of the Seabrook EPZ Sensiti-vity Study. We intend to finalize the criteria following further discussions or additional NRR coments by September 23, 1986.

Drielael sic d ey,

t. Q Jorden Edward L. Jordan, Director Division of Emergency Preparedness and Engineering Response Office of Inspection and Enforcement

Enclosure:

Draft of Technical Criteria DISTRIBUTION:

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Criteria to Evaluate Seabrook EPZ Sensitivity Study The size of the present plume exposure Emergency Planning Zone (EPZ) is detemined from considerations given in NUREG-0396. The rationale is also succintly stated in NUREG-0654 as follows:

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a. projected doses from the traditional design basis .

accidents would not exceed Protective Action Guide levels outside the zone;

b. projected doses from most core melt sequences would not exceed Protective Action Guide levels outside the zone; i c. for the' worst core melt sequences, imediate life threatening 4

doses would generally not occur outside the zone; i

d. detailed planning within 10 miles would provide a substantial i

base for expansion of response efforts in the event that this  ;

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Figure !.11 from NUREG-0H6 which displays whole body doses vs. distance, '

I given a core-melt, graphically illustrates the second and third factors l

given above. The data from Figure 1-11 are based upon the WASH-1400 c I

i release categories PWR1 through PWR7 (those sequences resulting in l

core-relt), and are for the Surry plant.

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1 Although NUREG-0654 indicates that the doses from traditional design basis accidents (06A) were also a factor, the staff concludes that relatively little weight should currently be given to this aspect since the traditional 08A, as postulated and evaluated, represents a highly stylized event intended primarily to assure the adequacy of the site and the performance of certain plant safety features, rather than representing a realistic portrayal of accident risks a'nd doses.

Since the WASH-1400 risk portrayal of the Surry plant was a niajor factor in the selection of the size of the plume exposure EPZ. an evaluation of the Seabrook EPZ sensitivity study should provide an assessment of the probability of various offsite doses at given distances, given a core-melt at Seabrook.

Consequently, the full range of doses vs. distance analagous to those shown in Figure I-11 of NUREG-0396 should be developed and displayed for the S plant. This will require an evaluation of Seabrook-specific information relating to probabilities of severe accident sequences, containment . failure modes and probabilities, release characteristics, and finally, dose calculation.

The doses vs. distance obtained for Seabrook can then be compared to Figure heb3 .. J.. ' ., -

I-11 of MUREG-0396 and a judgment on core-melt risks rf :f a___,

! may then be reached. ,

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