CHALLENGES IN CLASSIFYING LOW SPECIFIC ACTIVITY MATERIAL AND SURFACE CONTAMINATED OBJECTS

Commercial low level radioactive waste (LLW) destined for near surface disposal in the United States (US) must be properly characterized using the given facility’s waste acceptance criteria (WAC) which, at a minimum, for NRC licensed disposal facilities, must incorporate the US Nuclear Regulatory Commission (NRC) waste classification criteria [1], or Department of Energy (DOE) Order 435.1 when destined to a DOE LLW disposal facility [2]. The packaging and transportation of the LLW offsite is subject to the regulations of the US Department of Transportation (DOT) Hazardous Materials Regulations [3]. Challenges are faced by those responsible to characterize LLW for disposal and classify it again for transport – differing scopes in establishing the requirements; differences in terminology; similar terms with different meanings; different nuclide distribution allowances; differing activity limits, and others. The information necessary for LLW characterization may not be sufficient to properly determine DOT classifications. The complexities of the DOT Hazardous Materials Regulations are further increased by the challenges in categorizing LLW for packaging and transport as Low Specific Activity (LSA) material and Surface Contaminated Objects (SCO). A single system to characterize LLW for proper facility acceptance and disposal, and packaging and transport may be impractical – the criteria applied by each differ such that independent assessments must be completed against each specified requirement. Furthermore, LLW generation activities must be assessed separately and LLW characterization and classification methodologies prepared that adequately address chemical, radiological, and physical parameters of what may be expected. The two areas of concern addressed in this paper are: (1) the necessity of classifying SCO; and (2) the differences between NRC waste characterization and DOT radioactive material classification criteria for LSA material and SCO. Three assumptions have been incorporated into the preparation of this paper: 1. Commercial and some DOE-generated LLW will be transported offsite to a NRC licensed disposal facility. 2. Some DOE-generated LLW will be transported offsite to a DOE LLW disposal facility. 3. The methodologies applied for LLW characterization are shared regardless of its final destination (i.e., NRC or DOE disposal facility).