Document: NUREG-0800
Document ID: 2133c57c-1767-4769-89e9-ceb528fb7c2b
Document Type: srp
Title: RADIOLOGICAL CONSEQUENCES OF STEAM GENERATOR TUBE FAILURE
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350149.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.6.3
CFR Part: 
CFR Title: 

Content:
NSSS vendor standard 15.6.3-3 Rev. 2 - July 1981 technical specifications or from the plant-specific technical specifications (i.e., concurrent iodine spike case). 7. Evaluation of the effects of fuel failure. As a result of the steam generator tube rupture accident, fuel failures can occur, releasing fission products into the reactor coolant and thus making additional activity available for release to the atmosphere. The RSB reviews the effects of the accident on the core thermal margins and the associated amount of fuel failures, assuming that the highest worth control rod is stuck at its fully withdrawn position. The RSB, as a secondary review branch, informs the AEB of the fuel failure estimate. If the accident is predicted to cause such fuel failure, the dose analysis will be performed with the corresponding iodine activity but without a concurrent iodine spike. 8. Determination of the primary to secondary system leakage in the unaffected steam generators. The operating primary-to-secondary leakage is assumed to exist in the unaffected steam generators. at the maximum rate allowed by the standard technical specifications (Ref. 3, 4, and 5). This value is 1 gpm. However, a lower value may be needed to limit the consequences of other events such as a control rod ejection accident. j 9. Determination of the coolant flow through the failed tube. In conjunction with review step (3) above the flow rates through the two ends of the failed tube are calculated using a suitable flow model, taking credit for critical flow where appropriate. 10. Determination of the iodine transport to the atmosphere. The iodine transport model to be used is described in Reference 8. A fraction of the iodine in the primary coolant escaping to the secondary system is assumed to become airborne immediately due to flashing and atomization. Credit may be given for. "scrubbing" of iodine contained in the steam phase and in the atomized primary coolant droplets suspended in the steam phase for