(Question Posted to ERAD in May 2012)

A question on DOE O 458.1, CRD, 2.g.(4). When performing the analysis, I envision performing a settleable solids test such as Standard Methods 2540 F, Settleable Solids, and then performing gross alpha and gross beta analysis. Is this the correct interpretation of the requirement or does isotopic analysis of the settleable solids need to be performed?

Yes, this is a correct interpretation of the requirement. Guidance on this topic is provided in Environmental Regulatory Guide for Radiological Effluent Monitoring and Environmental Surveillance (DOE/EH-0173T); January 1991).

However; we do note an error in DOE O 458.1 in that gamma was mistakenly left out of the 50 pCi/g criteria – it should be 50 pCi/g beta-gamma emitters as it was in DOE 5400.5. EHSS is proposing a page change as part of the DOE O 251.1 required accuracy review.

Background

The following background information is provided to clarify this issue and to identify additional opportunities to meet the requirements of DOE O 458.1. Environmental Regulatory Guide for Radiological Effluent Monitoring and Environmental Surveillance (DOE/EH-0173T; January 1991) provides guidance for this analysis in Section 5.10.4, "Settleable Solids in Effluent Discharge" (pp. 5-32 and 5-33). For determination of alpha-emitting and beta-emitting radionuclide concentrations in settleable solids, this section references measurement recommendations in Section 6.4. Because the criteria for compliance with the settleable solids requirements are in terms of gross alpha and gross beta-gamma criteria, rather than radionuclide-specific criteria, the recommendation in Section 6.4 that gross measurements not be used to characterize a sample is not applicable to assessing settleable solids for compliance with DOE O 458.1 4.g.(4). Section 6.4 recommendations relating to the use of gas-proportional counters for gross alpha and beta measurements and gamma spectrometers for gross gamma are correct; however, other methods may be employed if they meet data quality objectives.

It is important to note that this is a standard-based requirement. If the defined collection process does not recover a quantity of settleable solids that is sufficient to detect the criteria, then the releases are in de facto compliance. There is no intent to require extraordinary measurements to determine gross alpha, beta or gamma activity in microgram samples.

Summary

Any analysis method providing gross activity concentrations with detection levels (MDA and uncertainty) suitable to meet the requirements in DOE O 458.1 is adequate for evaluation of settleable solids.