Document: NUREG-0800
Document ID: 37e64905-5f3c-4221-9ce6-b3089b164d6f
Document Type: srp
Title: LONG-TERM DIFFUSION ESTIMATES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070237.pdf
Revision Date: 2023-06
Chapter: 2
Section ID: 2.3.5
CFR Part: 
CFR Title: 

Content:
ters. Use of these parameters should be substantiated as to their appropriateness for use in 2.3.5-3 DRAFT Rev. 3 - April 1996 estimating the consequences of routine releases from the site boundary to a radius of 50 miles 80 km (50 mi) from the plant. 12 3. Meteorological data used as input to the dispersion models. Data used for this evaluation should represent hourly average values of wind speed, wind direction, and atmospheric stability which are appropriate for each mode of release and which are characteristic of annual average atmospheric transport and diffusion conditions in the vicinity of the plant. (See SRP Section 2.3.3 for data acceptability criteria, and see Regulatory Guide 1.23 for data formats.) 4. Relative concentration (X/Q) and relative deposition (D/Q) values used for assessment of consequences of routine radioactive gas releases as described in Section 2.3.5.2 of Regulatory Guide 1.70. 5. Points of routine release of radioactive material to the atmosphere, the characteristics of each release mode, and the location of potential receptors for dose computations.13 For a design certification review, the probability distributions for X/Q should be in the site parameter envelope specified for the standardized design.14 Technical Rationale15 The technical rationale for application of the above acceptance criterion is discussed in the following paragraphs:16 Compliance with the numerical guides for doses specified in 10 CFR Part 50, Appendix I, requires that the nuclear facility be operated to meet the criterion "as low as is reasonably achievable" (ALARA). 10 CFR 20.1301 establishes radiation dose limits to individual members of the public from radioactive effluents in unrestricted areas near a nuclear facility. In addition, 10 CFR 20.1101 states that licensees should, in addition to complying with the limits set forth in 10 CFR Part 20, make every reasonable effort to maintain radiation exposures, and releases of radioactive materials in effluents to