ASTM C1237-99(2005)

Hand-held SNM monitors are an effective and unobtrusive means to search pedestrians or vehicles for concealed SNM when automatic SNM monitors are not available or have sounded an alarm. Facility security plans apply SNM monitors as one means to prevent theft or unauthorized removal of SNM from designated areas. Functional testing of monitors on a daily basis with radioactive sources can assure they are in good working order. The significance of a less frequent, in-plant evaluation of an SNM monitor is to verify that the monitor achieves an expected probability of detection for an SNM or alternative test source.

The evaluation verifies acceptable performance or discloses faults in hardware or calibration.

The evaluation uses test sources shielded only by normal source encapsulation. However, shielded SNM test sources could be used as well.

The evaluation, when applied as a routine operational evaluation, provides evidence for continued compliance with the performance goals of security plans or regulatory guidance.

Note 1—It is the responsibility of the users of this guide to coordinate its application with the appropriate regulatory authority so that mutually agreeable choices for evaluation frequency, test sources, detection criteria (whether a single or multiple alarms constitute detection), minimum distance for first detection, number of trials, and reporting procedures are used. Regulatory concurrence should be formally documented.

1.1 This guide is one of a series on the application and evaluation of special nuclear material (SNM) monitors. Other guides in the series are listed in Section 2, and the relationship of in-plant performance evaluation to other procedures described in the series is illustrated in Fig. 1. Hand-held SNM monitors are described in of Guide C1112, and performance criteria illustrating their capabilities can be found in Appendix X1.

1.2 The purpose of this guide to in-plant performance evaluation is to provide a comparatively rapid procedure to verify that a hand-held SNM monitor performs as expected for detecting SNM or alternative test sources or to disclose the need for repair. The procedure can be used as a routine operational evaluation or it can be used to verify performance after a monitor is calibrated.

1.3 In-plant performance evaluations are more comprehensive than daily functional tests. They take place less often, at intervals ranging from weekly to once every three months, and derive their result from multiple trials.

1.4 Note that the performance of both the hand-held monitor and its operator are important for effective monitoring. Operator training is discussed in Appendix X2.

1.5 The values stated in SI units are to be regarded as standard.

1.6 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

Note—The procedures shown “above” the user provide the user with information before acquiring a monitor, and those “below” assist the user to obtain continuing acceptable performance from the monitor.