The previous section has outlined the effects of radioactivity and the limits placed by the ICRP and AEC on radioactive releases from nuclear power plants. The AEC regulations are based upon maximum exposures during or following a release at points on specified site boundaries, which are also part of the regulations.

5.2.1 Radiation Safety

One of the barriers mentioned at the commencement of this chapter was the physical distance which separates the public from the nuclear power plant. This barrier is defined by the following boundaries:

+ Higher altitude changes average 300 ft/5 mrem/yr increase.

a. Exclusion area. This is the area over which the reactor licensee has complete control. Residency is prohibited, or if there are residents, they are subject to immediate evacuation. There can be roads and waterways, but arrangements are made to control traffic if the need ever arises (Fig. 5.3).

b. Low population zone. This is the area around the plant that has a sufficiently low population so that arrangements can be made for their health and safety by evacuation or shelter. An exact population is not specified by the regulations, although the AEC would review the arrange­ments made for the emergency protection of residents in the zone (Fig. 5.3).

c. Population center distance. A population center containing more than 25,000 residents is considered a densely populated area, therefore the plant should be no nearer to such a population center than four-thirds of the low population boundary distance (Fig. 5.3).

It is clear that these boundary limits will vary for different plants in different areas. At the present time, for the LWR systems, the exclusion distance varies between 0.2 and 0.5 miles, a normal site boundary fence distance, while the low population zone varies between 1.4 and 7.4 miles. The radiation dose limits for these boundaries are set out in full in Section 5.1.3.3.

5.2.2 Other Siting Considerations1′

Many other practical considerations determine the choice of a site of a fast reactor power plant besides the radiation limitations. The following list enumerates some siting characteristics of interest.

(a) Population density. Is sufficient unpopulated area available to meet the requirements of the previous section?

(b) Present uses of the area. Could a power plant be built in the area without disturbance to the present use of the area; for example, is it all prime agricultural or conservation land?

(c) Physical characteristics (geology, seismology, hydrology, and meteo­rology). Would the physical characteristics of the site make a power plant overcostly or unlicensable in view of the geological, seismological, hydro­logical, or meteorological difficulties?

(d) Economic location with respect to the load center. Is the site close to or far from the center of load demand or a suitable distribution grid?

(e) Proximity to water or convenience of cooling ponds or towers. Can sufficient and adequately reliable cooling water be supplied (see also Sec­tion 6.4)?

(f) Site size. Is the site large enough for any future expansion planned?

(g) Transportation facilities. Are adequate roads, railways, and water­ways available for incoming plant components during construction?

(h) Labor availability. Is a labor force available in the proximity of the site to provide construction labor?

(i) Attitude of the local community. Is the local community liable to help or hinder the project? What local political situation might affect the site (see also Section 6.4)?

(j) Reactor characteristics. Does the site have any particular attractive­ness for the type of reactor under consideration?

These and other similar questions all require answering before a site can be selected. Many of these questions are not safety matters, but almost all are licensing matters.

Section 5.2.4 describes a standard site, Middletown, USA, in detail and examples of answers to the above questions are given in the description. In addition, Section 6.4 discusses the licensing problems associated with present day siting in the context of disturbances to the ecology: air pollu­tion, thermal effects, and aesthetic effects. The following section treats the effects of meteorology in more detail.

+ See also Section 6.4.