Extremity Dosimetry - STD-1128-98master0186

DOE-STD-1128-98

Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities

Personnel Dosimetry. The National Institute of Standards and Technology (NIST) has

also established the National Voluntary Laboratory Accreditation Program (NVLAP) for

testing and accreditation of dosimeter processors serving commercial industry and

medical facilities. Because the dosimetry needs at many DOE facilities, particularly

those processing plutonium, are different from commercial industries, the DOE initially

established a broader and more stringent accreditation program. Both DOELAP and

NVLAP accreditation programs use performance tests that evaluate the accuracy and

precision of personnel dosimetry measurements. The accuracy is determined by

comparing the measured dose equivalent to the "conventionally true dose equivalent"

derived from calibration standards directly traceable to NIST in carefully controlled

conditions.

The general methods used to calibrate the dosimeters are given in the National Bureau of

Standards Special Publication 633, Procedures for Calibrating Neutron Personnel

Dosimeters (Schwartz and Eisenhauer, 1982). Two laboratories conduct the performance

test irradiations for the DOELAP and NVLAP programs: Pacific Northwest National

Laboratory of Richland, Washington, and the Radiological and Environmental Sciences

Laboratory (RESL) of Idaho Falls, Idaho. Dosimeters are submitted for testing to the

performance testing laboratories in specified categories. If the dosimeter passes certain

accuracy and tolerance testing criteria, a team of dosimetry experts visit the processor

and/or site and assess the operation of the dosimetry program, including dosimetry

records and data retrieval systems, before the dosimeter processor or DOE site is

accredited. DOE requirements are given in the U. S. Department of Energy Standard

Laboratory Accreditation Program for Personnel Dosimetry Systems, DOE STD-1095-

95 (DOE 1995h). At present, both whole body personnel dosimeters and extremity

dosimeters are being tested, with extremity dosimeter testing currently being voluntary.

DOE will formalize the extremity dosimetry accreditation program in the near future.

6.3.3

Extremity Dosimetry

Doses to the extremities from plutonium processing and handling can involve significant

exposures to the skin of the hands and forearms. Doses over small areas of the skin are

discussed in Section IV.B.2. of Implementation Guide. External Dosimetry Program

(DOE, 1999e) and will not be discussed here. That Section discusses skin contamination

including hot particles, and the determination of skin dose from these events.

Highly accurate measurement of the dose to the hands and forearms is especially difficult

because of the low-energy photons (L x-rays and 60-keV photons from 241Am). Small

variations in shielding, such as differences in the thickness of gloves used in glove

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