Document: NRC Regulatory Guide
Document ID: 4d46a966-d280-43da-9b03-8b0abe7b29ce
Document Type: regulatory_guide
Title: Alternative Radiological Source Terms for Evaluating Design Basis Accidents at Nuclear Power Reactors (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2120/ML21204A065.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.183
CFR Part: 
CFR Title: 

Content:
ncipal design criteria may use this guidance. The following guidance should be used in determining the TEDE for persons located in the control room. 4.2.1 Sources of Radiation The TEDE analysis should consider all sources of radiation that will cause exposure to control room personnel. The applicable sources will vary from facility to facility, but typically will include the following: a. contamination of the control room atmosphere by the intake or infiltration of the radioactive material contained in the radioactive plume released from the facility, b. contamination of the control room atmosphere by the intake or infiltration of airborne radioactive material from areas and structures adjacent to the control room envelope, c. radiation shine from the external radioactive plume released from the facility, d. radiation shine from radioactive material in the reactor containment, and e. radiation shine from radioactive material in systems and components inside or external to the control room envelope (e.g., radioactive material buildup in recirculation filters). 4.2.2 Materials Releases and Radiation Levels The radioactive material releases and radiation levels used in the control room dose analysis should be determined using the same source term, in-plant transport, and release assumptions used for determining the EAB and the LPZ TEDE values, unless these assumptions would result in nonconservative results for the control room. 4.2.3 Transport Models The models used to transport radioactive material into and through the control room,14 and the shielding models15 used to determine radiation dose rates from external sources, should be structured to provide suitably conservative estimates of the exposure to control room personnel. 4.2.4 Engineered Safety Features The licensee may assume credit for ESFs that mitigate airborne radioactive material within the control room. Such features may include control room isolation or pressurization or intake or recirculation