DEVELOPMENT OF VERY LOW-LEVEL RADIOACTIVE WASTE SEQUESTRATION PROCESS CRITERIA

2015 ◽  
Vol 4 (2) ◽  
pp. 119-123
Author(s):  
Nicholas Chan ◽  
Pierre Wong

Segregating radioactive waste at the source and reclassifying radioactive waste to lower waste classes are the key activities to reduce the environmental footprint and long-term liability. In the Canadian Standards Association’s radioactive waste classification system, there are 2 sub-classes within low-level radioactive waste: very short-lived radioactive waste and very low-level radioactive waste (VLLW). VLLW has a low hazard potential but is above the Canadian unconditional clearance criteria as set out in Schedule 2 of Nuclear Substances and Devices Regulations. Long-term waste management facilities for VLLW do not require a high degree of containment and isolation. In general, a relatively low-cost near-surface facility with limited regulatory control is suitable for VLLW. At Canadian Nuclear Laboratories’ Chalk River Laboratories site an initiative, VLLW Sequestration, was implemented in 2013 to set aside potential VLLW for temporary storage and to be later dispositioned in the planned VLLW facility. As of May 2015, a total of 236 m3 resulting in approximately $1.1 million in total savings have been sequestered. One of the main hurdles in implementing VLLW Sequestration is the development of process criteria. Waste Acceptance Criteria (WAC) are used as a guide or as requirements for determining whether waste is accepted by the waste management facility. Establishment of the process criteria ensures that segregated waste materials have a high likelihood to meet the VLLW WAC and be accepted into the planned VLLW facility. This paper outlines the challenges and various factors which were considered in the development of interim process criteria.

1995 ◽  
Author(s):  
J.W. Jr. McConnell ◽  
R.D. Rogers ◽  
J.D. Jastrow ◽  
W.E. Sanford ◽  
T.M. Sullivan

Author(s):  
P. Poskas ◽  
J. E. Adomaitis ◽  
R. Kilda

The growing number of radionuclide applications in Lithuania is mirrored by increasing demands for efficient management of the associated radioactive waste. For the effective control of radioactive sources a national authorization system based on the international requirements and recommendations was introduced, which also includes keeping and maintaining the State Register of Sources of lonising Radiation and Occupational Exposure. The principal aim of the Lithuania’s Radioactive Waste Management Agency is to manage and dispose all radioactive waste transferred to it. Radioactive waste generated during the use of sources in non-power applications are managed according to the basic radioactive waste management principles and requirements set out in the Lithuanian legislation and regulations. The spent sealed sources and other institutional waste are transported to the storage facilities at Ignalina NPP. About 35,000 spent sealed sources in about 500 packages are expected until year 2010 at Ignalina NPP storage facilities. The existing disposal facility for radioactive waste from research, medicine and industry at Maisiagala was built in the early 1960’s according to a concept typical of those applied in the former Soviet Union at that time. SKB (Sweden) with participation of Lithuanian Energy Institute has performed assessment of the long-term safety of the existing facility. It was shown that the existing facility does not provide safe long-term storage of the waste already disposed in the facility. Two alternatives were defined to remedy the situation. A first alternative is the construction of a surface barrier and a second one is a retrieval solution, whereby the already stored waste will be retrieved for conditioning, characterisation and interim storage at Ignalina NPP. Facilities for the processing of the institutional radioactive waste are required before submittal to Ignalina NPP for storage, since the present facilities are inadequate. Feasibility study to establish a new central facility has been performed by SKB International Consultants (Sweden) with participation of Lithuanian Energy Institute. This study has identified the process applied and equipment needed for a new facility. Reference design and Preliminary Safety Assessment have also been performed. Plans for the interim storage and disposal of the institutional waste are described in the paper. The aspects of finging safe disposal solutions for spent sealed sources in a near surface repositories are also discussed.


2015 ◽  
Vol 11 (4) ◽  
pp. 10-20
Author(s):  
Lidia Radu ◽  
Nastasia Saca ◽  
Claudiu Mazilu ◽  
Maria Gheorghe ◽  
Ionela Petre

Abstract The cement based grouts, as functional performance composite materials, are widely used for both immobilisation and encapsulation as well as for stabilization in the field of inorganic waste management. Also, to ensure that low level radioactive waste (LLW) are contained for storage and ultimate disposal, they are encapsulated or immobilized in monolithic waste forms, with cement –based grouts. The paper includes some research data referring to cement based grout mix design for use as encapsulating/immobilizing system for low level radioactive waste. The work includes cement-based-grout mix design method used practically into establishing of the optimum grout mix based on the water/cement ratio, cement/sand ratio in order to achieve application requiered values of fluidity, segregation resistance, shrinkage and mechanical strengths. These engineering grout characteristics present relevance for simulation experiments of radionuclide leaching from LLW – cement grout encapsulation system.


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