Additional Guidance

DOE-STD-6003-96

2.2.2 Additional Guidance

10 CFR 100 defines requirements for siting of nuclear reactor facilities. These guide-

lines have also been applied to nonreactor nuclear facilities (DOE 6430.1A). According to

10 CFR 100.11, the maximum calculated dose to an off-site individual from exposure that

results from internal and external sources of radiation must not exceed 250-mSv (25-rem),

50-yr CED to the whole body. If multiple organs receive doses during the same exposure, the

ED shall not exceed 250 mSv (25 rem). The exposure duration should be consistent with the

requirement for no public evacuation. DOE 6430.1A recommends using meteorological condi-

tions that result in unfavorable dispersion (e.g., the higher of the 0.5% χ/Q for each sector of the

site and the 5% direction independent χ/Q for the site). In the absence of site-specific meteor-

ology, conservative assumptions (Class F, 1.0-m/s wind speed) should be used for design

assessments. Further guidance is contained in Sections 2.4.3 and 5.4.3.

DOE Order 6430.1A notes that these values are guidelines and do not constitute accept-

able limits on the doses to the public in the event of an accident. These guidelines are used by

DOE to evaluate the facility design in combination with the site characterization with respect to

the risk to the public from low-probability accidents. Accidents to be evaluated for comparison to

these dose guidelines include events with a probability of occurrence >106/yr. When the doses

are calculated, the degraded performance of engineered safety features and administrative

controls should be assumed unless they can be shown to be capable of performing their safety

function.

The radionuclides of concern in a fusion facility cover a wide range of characteristics.

Tritium is generally the most mobile. Tritium is hazardous if it is taken into the body via inges-

tion, inhalation, or absorption through the skin. Because of the relatively low energy of the beta

particle, 18-keV maximum energy, it does not present a significant hazard outside the body.

Other radionuclides are the products of neutron activation. These radionuclides, usually imbed-

ded in a metal, have much higher energies and undergo γ-decay. Typical radionuclides are

Fe-55, Co-58, Co-60, Mn-54, Mn-56, Ni-59, and Ni-63. Alloying elements and impurities further

increase the range of activation products.

2.2.3 Environment

Radiation protection standards have been developed expressly for the protection of

humans. It has been generally accepted that by protecting humans we are protecting the

environment. Recently, the ICRP stated (ICRP 1991):

The Commission believes that the standard of environmental control needed to protect

man to the degree currently thought desirable will ensure that other species are not put at risk.

Occasionally, individual members of non-human species might be harmed, but not to the extent

of endangering whole species or creating imbalance between species.

Additional guidance on other areas of environmental protection is provided in Chapter 3.