Biological effects of internally deposited plutonium - DOE-HDBK-1141-2001

Radiological Assessor Training

DOE-HDBK-1141-2001

Student's Guide

1. Plutonium-238 (half-life = 87.7 yrs) is most

commonly used as a heat source in

thermoelectric generators. Because of its heat

production, care must be taken in handling

gram or larger quantities, as it could melt

plastic or ignite other materials.

2. Plutonium-239 (half-life = 24,000 yrs) is the

primary component of plutonium reactor fuel

(>85%) and weapons grade plutonium (>90%),

with Plutonium-240 (half-life = 6,560 yrs)

constituting most of the remainder in both

cases.

3. Plutonium radioisotopes emit relatively few

high-energy gamma rays, so kilogram

quantities can often be processed without

serious gamma dose problems. However,

small amounts of some radioisotopes or decay

products can increase external dose. For

example, Plutonium-241 decays by beta

emission to Americium-241, which emits a 60-

keV gamma ray. This can be a significant

source of dose to hands in glove boxes.

4. Neutron dose rates from spontaneous fission

and from alpha-neutron reactions with light

elements may be significant (e.g., 1 kg of

Pu-F4 (Pu-238) would have a contact neutron

dose equivalent rate of 4800 rem/hr).

B. Biological effects of internally deposited plutonium

The primary hazards from the most common

chemical form of plutonium (PuO2) are inhalation

and ingestion. This chemical form is relatively

insoluble. Therefore, uptake through the gastroin-

testinal (GI) system following an ingestion is

small.

Inhaled plutonium can remain in the lungs for a

considerable time before being removed through

the lymph system.

Module 8 - 1