Document: NUREG-0800
Document ID: 23a67737-6e7e-4dfc-9090-dca6a186a7dc
Document Type: srp
Title: RADIOLOGICAL CONSEQUENCES OF MAIN STEAM LINE FAILURES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070679.pdf
Revision Date: 2023-06
Chapter: 15
Section ID: 15.1.5
CFR Part: 
CFR Title: 

Content:
dent iodine spike case). The primary coolant iodine concentration for this case is obtained from Figure 3.4.16-1 of the NSSS vendor standard technical specification (Ref. 2, 3, or 4) 29 30 or from the plant-specific technical specifications proposed in Chapter 16 of the applicant's SAR, as appropriate. (b) The reactor trip and/or primary system depressurization associated with the MSLB creates an iodine spike in the primary system (i.e., concurrent iodine spike case) (Refs. 56 and 67). The increase in primary coolant iodine concentration 31 32 is estimated using a spiking model which assumes that the iodine release rate from the fuel rods to the primary coolant (expressed in becquerels (curies) per 33 unit time) increases to a value 500 times greater than the release rate corresponding to the iodine concentration at the equilibrium value stated in the NSSS vendor standard technical specifications or from the plant-specific technical specifications, as appropriate (i.e., concurrent iodine spike case). 5. Evaluation of the effects of fuel failure. As a result of the MSLB accident, fuel failures can occur, releasing fission products into the reactor coolant and thus making additional activity available for release to the atmosphere. The RSBSRXB reviews, under SRP Section 15.1.5, the effects of the MSLB 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margins and the associated amount of fuel failures, assuming that the highest worth control rod is stuck at its fully withdrawn position.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 RSBSRXB, as a secondary review branch, will inform the AEB PERB of the fuel failure estimate. If the MSLB accident is predicted to cause such fuel failure, a dose analysis will be performed with the corresponding iodine activity but without a concurrent iodine spike. 6. Determination of the primary-to-secondary leakage. Normal operating primary-to-secondary leakage is assumed to exist in the steam generators. The leakage rate should be the maximum allowed by the technical specifications. This value is 1 gpm in