Document: NUREG-0800
Document ID: dbd67338-fe87-44c6-8578-3715167e447b
Document Type: srp
Title: SPENT FUEL CASK DROP ACCIDENTS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350315.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.7.5
CFR Part: 
CFR Title: 

Content:
ed be evaluated. If a radiological consequence calculation is found to be necessary, the procedure is as follows: 1. The fuel element gap inventory is determined in a manner similar to that for a fuel handling accident (see Ref. 3). The differences are that a longer decay time is allowed (earliest time after reactor fueling that cask loading operations commence) and the number of fuel elements involved is based on the largest capacity cask available or projected to be available. 2. If the drop is assumed to occur inside the refueling facility at a time when the facility is closed, and ESF-grade charcoal filtration is avail- able, credit may be allowed for iodine filtration. For the filters themselves, verification of acceptability.and efficiencies is provided by the ETSB. In a dual containment design where the fuel building may be exhausted through the standby gas treatment system (SGTS), AEB determines the relationship of the operational modes of the SGTS to the time sequence of the accident in order to give proper credit. 3. It the spent fuel drop is assumed to occur at a time when the facility is open to the outside atmosphere, an untreated puff release is assumed. 4. If a spent fuel cask is utilized in a containment structure which is not isolated during fuel cask transfer and ASB has determined that cask drop or tipping on spent fuel can occur, the radiological doses from all failed fuel will be evaluated. 5. The assigned meteorologist furnishes suitable X/Q values to determine the consequences of the accident. X/Q values are obtained for the exclusion area boundary and the boundary of the LPZ. 15.7.5-3 Rev. 2 - July 1981 6. The relevant plant parameters and the X/Q values are used to compute doses. The doses due to a postulated spent fuel cask drop accident are calculated at the exclusion area boundary and the boundary of the LPZ. 7. The calculated doses are compared with the acceptance criteria in subsection II. Where results of the dose calculations indicate