U.S. Nuclear Regulatory Commission
Question 373: What are the minimum requirements for height and access restrictions of barriers used to prevent entry to locked high radiation areas HRAs) and very high radiation areas (VHRAs) at nuclear power plants?
Answer: The NRC has prepared Regulatory Guide 8.38 that details control measures that should be implemented for such areas. This regulatory guide provides guidance on the following program elements as related to control of locked HRAs and VHRAs: management controls, procedural controls, training, communications and physical controls.
In general, there are no prescriptive, specific minimum height requirements for barriers preventing entry to locked HRAs and VHRAs. It is required that physical controls (such as barriers) provide assurance that individuals are not gaining unauthorized access to locked HRAs. For VHRAs, 10 CFR 20.1602 requires "additional measures to ensure that an individual is not able to gain unauthorized or inadvertent access." The NRC staff realizes that tools (wrenches, wire cutters, cutter torches) are readily available in a nuclear power plant and that it is virtually impossible to prevent determined willful circumvention of physical barriers. However, physical controls can and should be established so that any such willful acts are detectable (i.e., they result in cut locks or fencing, wall panels removed, etc). For example, the use of a fence to prevent access to a VHRA would not satisfy the requirements of 10 CFR 20.1602 if an individual could gain access to the VHRA by climbing over the fence.
(References: 10 CFR 20.1601, 10 CFR 20.1602)