Document: NRC Regulatory Guide
Document ID: de79d411-4fc9-456e-a5a0-f4a910ca4c9a
Document Type: regulatory_guide
Title: Assumptions Used for Evaluating a Control Rod Ejection Accident for Pressurized Water Reactors (Rev. 2)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2111/ML21119A157.pdf
Revision Date: 2023-05
Chapter: 
Section ID: RG-1.77
CFR Part: 
CFR Title: 

Content:
ot be considered further if the total shipment frequency for all hazardous chemicals (i.e., all hazardous chemicals considered as a singular cargo category without further distinction of the nature of these chemicals) does not exceed the specified number by traffic type and the total weight less than the quantity shown in Table 2. Licensees should use risk information, particularly when requesting related license amendments, as described in Section C.2 below. 2. RISK EVALUATION Releases of hazardous chemicals from stationary sources or from frequently shipped mobile sources in quantities that do not meet the screening criteria in the Sections C.1.1 or C.1.2 above should undergo detailed analyses for CR habitability. Licensees may provide risk information to demonstrate that the radiological risk to the public from such toxic chemical releases is small, consistent with the Commission’s Safety Goal Policy Statement, SECY-00-0077, “Modifications to the Reactor Safety Goal Policy Statement,” dated March 30, 2000 (Ref. 18). Releases of toxic chemicals that could potentially result in a significant concentration in the CR need not be considered for further detailed evaluation if the releases occur at a frequency of 1x10-6 per year or less because the NRC considers these resultant low levels of radiological risk to be acceptable. To facilitate risk-informed license amendments, risk information should be provided in accordance with the guidance set forth in Regulatory Guide 1.174. As explained in RG 1.174, one key principle in risk-informed regulation is that proposed increases in risk are small and consistent with the intent of the Commission’s Safety Goal Policy Statement. The safety goals and associated quantitative health objectives (QHOs) define acceptable level of risk as a small fraction (0.1%) of other risks to which the public is exposed. Procedures outlined in the “Framework for Risk-Informed Changes to the Technical Requirements of 10 CFR Part 50,” an