Table 2.2. Uses and Availabilities of Plutonium Isotopes

DOE-STD-1128-98

Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities

Table 2.2. Uses and Availabilities of Plutonium Isotopes

Isotope

Uses

Availability

236

Pu, 237Pu

Both available in microcurie quantities.(a)

Popular environmental and biological chemical

tracers.

238

Small thermal and electric-power generators.

Available in various isotopic enrichments,

ranging from 78% to 99+%.(a)

239

Available enrichments range from 97% to

Nuclear weapons and as a fast reactor fuel. Also,

99.99+%.(a)

frequently used in chemical research where

production-grade material of mixed isotopic content

is suitable.

240

Principally in flux monitors for fast reactors.

Available enrichments range from 93% to

99+%.(a)

241

The parent from which high-assay 241Am can be

Samples available in enrichments of 93%.(a)

isolated for industrial purposes.

242

For study of the physical properties of plutonium;

Samples available in enrichments ranging

also as a mass spectroscopy tracer and standard.

from 95% to 99.9+%; enrichments of

production-grade material range from 85% to

95%.(a)

244

Currently, the only isotope available as a National

Can be obtained from DOE's New Brunswick

Institute of Standards and Technology (NIST)

Laboratory.

(b)

Standard Reference Material (SRM).

(a)

Available in small quantities from the Oak Ridge National Laboratory (ORNL): ORNL Isotopes Sales Office, Oak Ridge

National Laboratory, P.O. Box X, Oak Ridge, Tennessee 37830.

A second NIST/SRM (a 1:1 mixture of 239Pu and 242Pu) is being prepared, and a third (239Pu) is planned for the future.

(b)

2.1.2 Laser Isotope Separation Process

Several new technologies are being considered to provide more highly purified plutonium

isotopes for various purposes. One of these processes, laser isotope separation (LIS), has the

potential to purify 239Pu from almost any source of plutonium. The LIS process produces a

product enriched in 239Pu and a byproduct that contains the remaining plutonium isotopes. It

is conceivable that the byproduct stream could be further purified to produce a specific

plutonium isotope, such as 238Pu used for isotopic heat sources.

The LIS process has many benefits. It can significantly reduce external radiation exposure

to both neutron and gamma radiations for the product enriched in 239Pu. (Potential exposure

problems from the byproduct stream are discussed later in this section.) The International

Commission on Radiological Protection (ICRP) and the National Council on Radiation

Protection and Measurements (NCRP) have recommended increasing quality factors to a

value of 20 for fast neutrons (ICRP, 1985; NCRP, 1987a). Thus, it may be desirable to

reduce neutron exposures. Neutrons arise primarily from even-numbered plutonium

isotopes (mostly 238Pu and 240Pu) as a result of spontaneous fission and alpha-neutron

reactions with low-atomic-number impurities in the plutonium. The 239Pu-enriched product

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