Federal emergency management agency fema rep-2, rev. 2 / June 1990

1.2Conceptual Guidance

For PAGs, the projected dose does not include dose that may have been received prior to the time of estimating the projected dose.^xiii A PAG does not imply an acceptable dose. (See Section 4.0 for a discussion of PAGs).

Protective Action Guides and guidance on the implementation of protective actions are being developed cooperatively by various Federal agencies^xiv for use by State planners to develop State radiological emergency preparedness plans. The PAGs are projected whole body or thyroid dose limit ranges which require protective actions. Since the PAGs are related only to whole body or thyroid doses, skin dose limitation will not be addressed in this document.

The FRPCC efforts in their development of radiological emergency preparedness guidance have been directed first towards light water nuclear power reactor accidents. If additional guidance on other types of radiological emergencies becomes necessary, it will become the subject of a separate guidance document.

The guidance reports on offsite emergency radiation measurement systems to be written by the FRPCC Subcommittee will usually follow the issuance of guidance on the implementation of protective actions. However, the recommendations of the original FEMA REP-2 report on Phase 1 of the Airborne Release were developed concurrently with the Federal interagency effort on development of PAGs and guidance on the implementation of protective actions.^xv

Insofar as possible, the FRPCC Subcommittee strives to define measurement systems that use instrumentation readily available to the States and/or local organizations at little cost, and which are useful in other normal and emergency radiation measurements. In this respect, it is important that each State or local organization review the adequacy and availability of its equipment for emergency monitoring. This is not intended to imply that more expensive and/or sophisticated equipment can not be used, if available.

Conceivably, the aggregation of the available instrument resources recommended for individual emergency radiation measurement systems may not be the most cost-effective mix of instrument resources for the emergency radiation measurement systems as a whole, i.e., the total system.

The generic instruments and equipment requirements and other resources recommended by the Subcommittee for use in offsite emergency radiation measurement systems are as follows:

1. 
   Plume Exposure Pathway.
   

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  Direct exposure measurements - calibrated low-range (0-50 mR/h) and high-range (0-100 R/h) survey instruments. GM or sealed ion chamber type instruments with moveable beta shields on the low-range instruments to provide open and closed window measurement capabilities.
  
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  Radioiodine measurements - calibrated air pumps with appropriate particulate filters, cartridge type adsorber filters (such as silver zeolite) for selective collection of radioiodine in the presence of noble gases. A thin window (1.5-2.0 mg/cm²) pancake type GM detector or a 1" x 1" or 2" x 2" NaI(Tl) detector with either a single channel or dual channel analyzer may be used to measure the radioiodine activity on the adsorber cartridge.
  
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  Personal dosimetry - calibrated direct reading dosimeters and permanent record dosimeters (see emergency worker exposure instrumentation).
  
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  Dose projection capability - a hand-held calculator is adequate for making thyroid dose rate projections in the field based on the field measurement data. However, a more sophisticated computer program may be desirable at the Emergency Operations Center (EOC). This program should have the capability of making dose projections based on release measurements obtained from the plant operators as well as the capability of accepting field measurement data as input for fine tuning the dose projections.
  
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  Communications – direct and, ideally, continuous communications ability is necessary between the field monitoring teams and the EOC or Forward Command Post. This is best accomplished by means of radio with backup systems, such as additional radios or public telephones, available in the event of equipment failure.
  

2. 
   Ingestion Pathway (see References 11 and 12).
   
3. 
   Other Resources.
   

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  Utility - the utility offsite field monitoring teams will be able to mobilize and respond to a potential offsite release of radioactivity more quickly than the State or local field monitoring teams. The offsite measurements made by the utility field monitoring teams should be used for early delineation of the plume boundaries and verification of initial dose projections. The combined measurement data from the utility and State or local monitoring teams will provide a better overall characterization of the plume. The utility may also be a resource for additional monitoring team personnel and monitoring instruments or equipment.
  
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  Federal Agencies - several Federal agencies have the capability of providing personnel and equipment resources for additional field monitoring and sample collection teams and radiological laboratory facilities (both mobile and fixed facilities). In addition, the Department of Energy (DOE) has the Aerial Measuring System program which should be used following releases of radioiodine or particulate radioactivity to determine the areal extent of ground surface radiological contamination caused by the deposition of radioactivity from the plume. During the course of an airborne release of radioactivity, dose projections, and predictions of ingestion pathway concentrations from DOE's Atmospheric Release Advisory Capability, an atmospheric modeling system based at Lawrence Livermore National Laboratory, may be available to State and local authorities.