Radioactive/Mixed Waste Problems and Strategies 10CFR61 Radioanalytical Techniques and Instrumentation Mixed Waste Analyses and Instrumentation
Authors: Banavali AD , Stagg DD , McCurdy DE , Harvey JT 
Published: March 2009

On December 27, 1982, after several years of deliberation, the U.S. Nuclear Regulatory Commission (NRC) published 10CFR61 code of regulations in the Federal Register. These regulations address the disposal of low-level radioactive wastes in near surface land disposal facilities. Included in this body of regulations is the classification of radwaste that the generator has to provide the waste collector or processor. This classification is based on the radioactivity content of the shipment and constitutes Class A, Class B and Class C based on progressive increases in radioactivity. Generally Class A type samples include dry active waste material while Class B and Class C include evaporator bottoms, primary system clean-up resins, microwynd filters, crud, etc.

The NRC Branch Technical position on waste classification also outlined an example program in its recommendations that the nuclear utilities generating waste must adhere to in order to be found in compliance with waste characterization regulations. In short, it assumes a periodic isotopic analysis for all nuclides listed in Table 1 of Section 61.55, gamma spectroscopy of certain radionuclides and gross radioactivity measurements that correlate with gamma spectroscopy measurements. Waste characterization must also be done whenever inherent plant operating conditions change, e.g. in plant shutdown, during refueling or a crud burst using an underlying assumption that the waste stream characteristics may have changed. Once a particular operating plant has evaluated its baseline for the waste streams involved, indirect methods of correlation may be used for certain hard-to-measure radionuclides by scaling factors. In addition to all these requirements, based on 10CFR20 regulations, shipping manifests of such waste must include total radioactivity, total quantity of H-3, C-14, Tc-99 and I-129 in the shipment, significant radionuclide contributors, etc. It is for all these reasons that it becomes imperative for a nuclear power plant to get the entire spectrum of analysis for 10CFR61 related waste.

The Yankee Atomic Electric Company Environmental Laboratory (YAEL) added a new dimension to its analytical services program in 1988 when it started processing samples for the 10CFR50 and 10CFR61 programs. As of today, all media in the waste streams from Pressurized Water Reactors (PWR) and Boiling Water Reactors (BWR) have been analyzed. This presentation shall provide an overview of the current radioanalytical techniques and instrumentation used in this program. It will also reflect on the problems encountered in processing and the strategies used to effectively resolve these issues.

International Technology Corporation (ITC) added mixed waste to its corporate capabilities in 1987 when it started processing radioactive samples for characterization of waste materials as defined in 40CFR261 and other regulatory requirements. The characterization includes: ignitability, corrosivity, reactivity and EP toxicity. The radiochemical characterization is important in determining how to handle mixed waste sample, i.e. different nuclides are handled differently. For lower levels of radioactivity, the test methods in SW-846 can be employed with little difficulty. However, the volume of material and elevated radioactivity requires the modification in the handling to meet the analytical requirements outlined in SW-846 and other regulatory guides.

This portion of the presentation will provide an overview of the current analytical techniques in SW-846 as applied to mixed waste samples. It will reflect the problems encountered in processing and the strategies to effectively resolve these issues while maintaining the quality objectives and implementing safety precautions for these techniques.