During the decommissioning of a mixed-oxide fuel fabrication facility, West et al.
(1991) used a nondestructive assay system to provide criticality safety monitoring,
track the plutonium inventory, provide measurement of decontamination
effectiveness, and provide quantitative characterization/assay of the waste. The
system consisted of an integrated set of two passive neutron networks, two pulsed
active neutron units, a high-resolution gamma spectrometer [high-purity germanium
(HPGe)], and a neutron-coincidence counting unit. Waste determined to be less than
10 nCi/g was certified as class A low-level waste (LLW).
4.2.7 ALARA Guidelines
Contamination levels should be maintained ALARA to minimize the potential for the
spread of contamination and to reduce the protective measures and equipment
required. Control of radioactive material at the source and prevention of the
generation of contamination are more effective and less costly than remediation.
PERSONNEL CONTAMINATION CONTROL
As described earlier, the purpose of contamination control is to prevent the ingestion or
inhalation of plutonium by workers. This is primarily achieved by the engineered barriers
discussed previously, containment, confinement, and ventilation control. Only if the
primary controls fail or if there is a potential for personnel contamination during an activity
are administrative controls such as protective clothing and respirators advisable.
4.3.1 Monitoring Philosophy
Monitoring the worker is necessary, not only to ensure that a potential intake is
detected promptly and that the resulting internal dose is assessed, but to confirm the
integrity of the engineered containment system and ensure the effectiveness of the
overall radiation protection program.
There are several types of worker monitoring, some during and immediately
following work with radioactive material and some scheduled for a later time at a
preset frequency. This section addresses only methods of monitoring the worker at
the workstation. Other methods are discussed in the section that deals with internal
and external exposure controls.