ML20059E160
| ML20059E160 | |
| Person / Time | |
|---|---|
| Issue date: | 09/06/1990 |
| From: | Tokar M NRC OFFICE OF NUCLEAR MATERIAL SAFETY & SAFEGUARDS (NMSS) |
| To: | Randy Baker NUS CORP. |
| References | |
| REF-WM-3 NUDOCS 9009100054 | |
| Download: ML20059E160 (3) | |
Text
LTR RBAKER MT SEP 0 61993 Mr. Richard Baker NUS Corporation 910 Clop >er Road Gaithers>urg, MD 20B79
Dear Mr. Baker:
Enclosed are three copies of a summary of a technical paper that I am submitting for the 1991 Joint International Waste Management Conference in Seoul, Korea.
This paper, which deals with the Nuclear Regulatory Commission's development of new guidance on low-level radioactive waste solidification /sttbilization, should be of considerable laterest to the international radioactive waste management community.
I would, therefore, appreciate your review and consideration of the sunnary and hope that the paper will be accepted for the Conference.
Thank you for your consideration.
Sincere ly, Original t@n:J ty Michael Tokar, Section Leader Engineering Section Technical Branch Division of Low-Level Waste Management and Decommissioning, HMSS Enclosure' As stated DIS RIBUTION:
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4 REGULATURY GUIDAFCE ON LOW-LEVEL WASTE FORM STABILITY by Dr. Michael Tokar U.S. Nuclear Regulatory Comission Washington, D.C.
Disposaloflow-levelradioactivewaste(LLW)isregulatedintheUnited States of America under the provisions of Part 61 to Title 10 of the Code of Federal Regulations (10 CFR Part 61). Part 61 establishes the procedures, criteria, and the terms and conditions upon which the Comission issues licenses for the disposal of radioactive wastes containing byproduct, source, and special nuclear material received from other persons. The regulation establishes three categories or classes of wastes: viz; Classes A, B, and C, in a generally ascending order of degree of hazard with respect to type and concentration of radionuclides. All three classes of wastes are required to meet certain " minimum requirements" regarding packaging, treatment of liquids, and avoidance of explosive, pyrophoric, or flamable materials, etc.
In addition, Class B and Class C wastes (and Class A wastes that are co-mingled
- with Classes B or C wastes) are required to be " structurally stable" for a long period of time after disposal (on the order of 300 years).
Though Part 61 provides the basic requirements for waste form stability, the regulation does not describe in any detail how those requirements can be satisfied. That type of guidance is presented in a documut called the
" Technical Position on Waste Form," which was formulated and issued in 1983.
For solidified waste forms, the Technical Position prescribes several kinds of qualification tests, along with acceptance criteria for each type of test.
The tests involve subjecting the waste specimens to conditions of compression, irradiation, biodegradation, leaching, imersion, and thermal cycling. Ost of the tests, which were selected for their relative simplicity and reproducibility, are based on American Society for Testing and Materials (ASTM) or American Nuclear Society (ANS) standard methods of test that were originally developed for non-radioactive material applications. These methods of test are intended to provide confidence, by exposing test specimens to relatively short-term (minutes to weeks) conditions, that LLW foms will have the desired long-term structural stability.
Part 61 became effective in early 1983. Since that time, there has been considerable experience gained with the use of solidification media, such as cement and bitumen, for stabilizing LLW. Though cement remains as the most widely used LLW solidification / stabilization medium, there have been several incidents with cement-solidified wastes at power reactors. These incidents have involveo problems with waste form expansion and disintegration, and the excessive retardation or acceleration of solidification. The difficulties encountered in the field have been matched by ex>erimental data obtained through numerous laboratory testing programs on )oth simulated as well as real LLW.
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In an attempt to obtain greater assurance that cement-solidified LLW forms will meet Part 61 stability requirements, the NRC staff has been revising the 1983 Technical Position on Waste Form.
Changes to the Technical Position include a new appendix, for cement-stabilized LLW, that provides modifications to the recommendations for qualification testing, as well as new guidance on waste characterization, specimen preparation, surveillance specimens, and mishaps reporting. This paper discusses the requirements for waste form stability that are contained in 10 CFR Part 61 and the improved guidance provided in the revised Tecnnical Position on Waste Form.
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