Document: NUREG-0800
Document ID: ddaa3c7d-ce79-4a3f-aaae-4e4436ab7bc1
Document Type: srp
Title: NUCLEAR DESIGN
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0707/ML070740003.pdf
Revision Date: 2023-06
Chapter: 4
Section ID: 4.3
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CFR Title: 

Content:
ansients, axial xenon reactivity transients, other possible xenon reactivity transients, and non-xenon-induced reactivity transients are discussed in sufficient detail so that the reviewer can confirm for each item that the method of calculation (e.g., nodal analysis, diffusion theory, transport theory, synthesis) and the number of spatial dimensions used (1, 2, or 3) are acceptable. F. Verification of the database, computer codes, and analysis procedures has been made by comparing calculated results with measurements obtained from critical experiments and operating reactors. The reviewer ascertains that the comparisons cover an adequate range for each item and that the conclusions of the applicant are acceptable. 8. The analysis of neutron irradiation of the reactor vessel may be used in two ways. It may provide the design basis for establishing the vessel material nil-ductility transition temperature as a function of the neutron fluence. Neutron fluence is the time integrated neutron fluence rate (i.e. neutron flux) as expressed in neutrons per square centimeter. Neutron fluence is often represented by the somewhat archaic term “nvt,” where “n” is the neutron density, “v” is the velocity, and “t” is the time interval. Or, it may provide the relative flux spectra at various positions between the pressure vessel and the reactor core so that the flux spectra for various test specimens may be estimated. This information is used in determining the reactor vessel material surveillance program requirements and pressure-temperature limits for operation under SRP Sections 5.3.2 and 5.3.3. The organization responsible for the review/assessment of nuclear design reviews the calculational method, the geometric modeling, and the uncertainties in the calculations under SRP Section. The review procedures for pressure vessel irradiation include determinations that: A. The calculations were performed by suitable radiation transport methods, that are fundamentally