Document: NRC Regulatory Guide
Document ID: ceaeb6d7-d85a-46d3-a1b6-70059a498965
Document Type: regulatory_guide
Title: 12/2001 (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0131/ML013100014.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.78
CFR Part: 
CFR Title: 

Content:
d to be shipped by rail, water, or road routes outside a 5-mile radius of a nuclear power plant, the shipments need not be considered further for evaluation for the same reason stated in the screening criteria for stationary sources. If the shipments are within a 5-mile radius of a nuclear power plant, estimates of the frequencies of these shipments should be considered in the evaluation of control room habitability. Shipments are defined as being frequent1 if there are 10 total shipments per year for truck traffic, 30 per year for rail traffic, or 50 per year for barge traffic. These frequencies are based on transportation accident statistics, conditional spill probability given an accident, and a limiting criterion for the number of spills or releases. These accident rates have remained relatively constant for many years, therefore it is not necessary to revise these frequencies (Ref. 5). Mobile sources need not 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. Frequent shipments, i.e., shipments exceeding the specified number by traffic type, need not be considered in the analysis if the quantity of hazardous chemicals is less than the quantity shown in the table in Appendix A (adjusted for the appropriate toxicity limit, meteorology, and control room air exchange rate). 1.78-5  TABLE 1 TOXICITY LIMITS (IDLH LIMITS) FOR SOME HAZARDOUS CHEMICALS Chemical Toxicity Limita Chemical Toxicity Limita ppmb mg/m3c ppmb mg/m3c Acetaldehyde Acetone Acrylonitrile Anhydrous ammonia Aniline Benzene Butadiene Butene Carbon dioxide Carbon monoxide Chlorine Ethyl chloride Ethyl ether Ethylene dichloride Ethylene oxide 2000 2500 85 300 100 500 2000 40000 1200 10 3800