Chemical Versus Radiological Hazards

DOE-STD-1128-98

Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities

possibility of a fire or explosion in a plutonium facility is probably the most serious threat

because the consequences of a fire could lead to loss of containment and subsequent dispersement

of highly mobile plutonium particulates. In addition, fighting the fire with water to maintain

containment could create the potential for a criticality accident and/or loss of containment in the

immediate vicinity.

The day-to-day hazards for personnel in plutonium facilities involve exposure to gamma rays,

X-rays, and neutrons, as well as possible accumulation of plutonium in the body. These hazards

are described in more detail in Section 3.0, "Radiation Protection," and Section 7.0, "Nuclear

Criticality Safety." The amount of plutonium needed to present potential hazards to personnel in

plutonium-handling facilities is summarized in Figure 2.4. Hazards related to interim and long-

term storage of plutonium will be found in Section 2.7, "Storage and Containment."

2.6.1

Chemical Versus Radiological Hazards

The radiological toxicity of reactor-produced plutonium far exceeds the chemical toxicity

of this heavy element. Furthermore, its low solubility in near-neutral or basic solutions

reduces the uptake through ingestion by a factor >1000 for any plutonium compounds

except certain complexes, such as the citrate or ethylenediamine tetraacetic acid (EDTA)

complex. (Refer to Sections 2.3, "Radiobiological Properties," and 6.0, "External Dose

Control"). Tipton (1960) summarizes the differences in chemical hazards between

plutonium and uranium: "In contrast to uranium, the chemical toxicity of plutonium is

insignificant in comparison to the hazard arising from its natural radioactivity."

Moreover, "the toxicity of plutonium and other transuranic elements," according to Voelz

et al. (1985), "has only been studied in animals since acute toxicity has never been

observed in man for these elements and epidemiologic studies have not produced positive

results." However, recent evidence suggests that plutonium can catalyze reactions

including oxidative stress in the absence of significant radioactive decay. These data

presented by Claycamp and Luo (1994) suggest that plutonium complexes might

contribute to long-term oxidative stress related to tumor promotion.

2.6.2

Associated Chemical Hazards

The main chemical hazard of plutonium is its vulnerability to oxidation and the

pyrophoricity of some of its alloys and compounds (see Section 2.6.3).

The processing of plutonium, including separation from irradiated uranium, purification,

conversion, waste disposal, environmental restoration, and D&D, necessarily requires the

use of chemicals and reagents with varying degrees of toxicity and hazardous properties.

A partial list of chemicals that are either used or proposed for use at DOE plutonium

facilities is provided in Table 2.9. An abbreviated evaluation of the potential hazards of

2-25