Surface Contamination Monitors.

DOE-STD-1128-98

Guide of Good Practices for Occupational Radiological Protection in Plutonium Facilities

conditions, while ANSI N42.17B gives a 15% limit of variation. As discussed

previously, criteria from ANSI N42.17B are more applicable because they are

supported by instrument testing.

ANSI N13.1 (ANSI, 1969a) provides detailed guidance on sampling methods. One

criterion that relates to CAMs is that air sample lines between air inlet and filter

media are to be eliminated where possible; where not possible, they are to be

designed to meet the sampling criteria contained in the standard (e.g., short lines,

proper sampling rate, smooth bends). The use of Tygon tubing as sample lines

before the collection filter should be minimized or eliminated. Air in-leakage from

surrounding areas can be a problem when using sampling lines. Testing for air

in-leakage shall be performed at least annually or when seals or "O" rings are

replaced.

Surface Contamination Monitors. Surface contamination monitors include hand

and/or shoe counters and instruments (or probes) with sufficient flexibility to

survey pieces of equipment, including exterior clothing. ANSI N317 (ANSI,

1980a) states that these instruments shall have an audible alarm, a frequency that is

proportional to the count rate, or a preselectable trip setting, and that upon reaching

that level shall activate an audible or visible alarm or both. These instruments

should be calibrated according to the requirements in ANSI N323 (ANSI, 1997b)

and be equipped with a traceable check source. Fixed instruments should be

source.

Photon and Neutron Area Monitors. Photon and neutron area monitors measure

the intensity of photon and neutron radiation in areas where significant quantities

of plutonium are stored and/or handled. ANSI N317 (ANSI, 1980a) states that

these monitors shall have a preselectable trip setting with audible annunciators,

shall provide electronic signals for remote alarms if they are used as alarming

devices, and shall be equipped with a visual meter or digital readout. All neutron

and photon area monitors should be AC-powered and all critical monitors should

be provided with an emergency power source. Many of the requirements that

apply to portable survey instruments, as stated in ANSI N317 may also apply to

this type of instrumentation. Calibrations should be performed according to the

requirements in ANSI N323 (ANSI, 1997b).

3.5.2.3 Performance Criteria for Emergency Instrumentation

Meeting the criteria for criticality accident alarm systems, fixed nuclear accident

dosimeters, and other emergency instrumentation is essential.

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