Improvement of radioactive waste characterization systems at Ukrainian operational NPP's and Procedures and methodology for clearance of materials from regulatory control

Fifteen operational WWER reactor units and the shutdown Chernobyl NPP with four RBMK reactors are the main source of radioactive waste in Ukraine. There are two principal ways to manage the radioactive waste:

• Processing, aimed at obtaining waste packages which are  suitable for long term storage or final disposal;
• Clearance from regulatory control of radioactive waste with radionuclide contamination below established limits.

The overall objective of the project was to improve safety and cost-effectiveness in the management of all types of radioactive waste in Ukraine and, in particular, to direct all the activities towards waste minimization and the permanent, safe disposal of radioactive waste. The entire project consists of two separate projects:

Project B - Improvement of radioactive waste characterization systems at Ukrainian operational Nuclear Power Plants

The overall objective of this project was the establishment of an improved system for the estimation of the radionuclide composition and activity levels of “difficult-to-measure” radionuclides in nuclear power plant (NPP) waste and processed waste packages. Improved systems shall be based on the well-established method of scaling factors application, that defines correlations between difficult-to-measure and easy to measure radionuclides in RAW.

The project results are:

• Detailed analysis of the world practice in the field of radioactive waste characterization at operational NPPs, with a special attention to definition of waste streams, identification of difficult-to-measure (DTM) radionuclides and corresponding marker radionuclides (MR) in waste streams and processed waste packages, and methods for obtaining scaling factors (SF) using results of radiochemical analysis of radioactive waste samples;
• A procedure for obtaining a practical list of critical radionuclides that should be considered in characterization of radioactive waste at nuclear power plants with WWER was proposed. Based on the detailed analysis of available technical information and world operational practice, the list of 12-14 critical radionuclides was recommended for consideration in establishing Waste Acceptance Criteria (WAC) for the operational and decommissioning radioactive waste of the nuclear power plants in Ukraine;
• A principal scheme of the waste streams at the nuclear power plants with WWER in Ukraine was developed and a procedure of précising and updating of individual waste streams was proposed. In spite of the limitations in determining the individual list of critical radionuclides (namely DTM radionuclides) in each waste stream, pairs of DTM <-> marker radionuclide have been identified for use in establishing scaling factors
• A justification for and an approach to the setting of scaling factors was provided and relevant documents for promoting the scaling factors system were developed. In particular: Sampling strategy for NPP waste streams and a methodology for the determination of the radionuclide composition and activity of DTM radionuclides in nuclear power plant waste
• Procedures for the use of markers and determination of difficult-to-measure radionuclides in RAW samples and processed waste packages were described and a document was developed with recommendations for the purchase of additional equipment for sampling and gamma radiometry of samples and RAW packages
• A document "Procedures for Sampling and Determination of Radionuclide Activity" was developed, describing in detail the collection of waste samples from all radioactive waste streams as well as a procedure for the calculation of scaling factors from results of radiochemical analysis of waste samples;
• A software package, DITA, was developed for the calculation of the concentration of difficult-to-measure radionuclides and the use of the scaling factors database;
• Theoretical and practical training sessions were prepared to transfer the technological experience and to increase the Beneficiary / End user's capabilities in obtaining, establishing and applying scaling factors to characterize radioactive waste at nuclear power plants. The goal of the practical training was to facilitate the correct and effective application of the theoretical results of the project, in particular, the identification of waste streams, ensuring representative sampling, performing calculation of the scaling factors and applying those scaling factors to estimate the activity of the DTM radionuclides in the radioactive waste.
• A final seminar for a wide range of representatives of organizations involved in the project was prepared to disseminate the project results. During the seminar, the contractor experts summarized achieved results of the project, presented the expected development in the field of establishing the scaling factor method in Ukraine, and presented recommendations for individual project tasks and for the project as a whole.

Project E - Procedures and methodology for clearance of materials from regulatory control
The Project E goal was to develop and recommend clearance methodology(ies) and procedures for application at NPPs, SC UkSA Radon, CRWME, and other relevant organizations of Ukraine, based on detailed analysis of the international standards and identification of the best world practice. Another objective was to develop the design ToR and technical specification of the facility for materials clearance from regulatory control at Chernobyl NPP.

This resulted in:

• An analysis of the international standards and best practices in the area of clearance of material from regulatory control and analysing the information regarding the current status of implementation of material clearance practices in Ukraine;
• The development of the document “Methodology of clearance from regulatory control of radioactive materials”, which can be used for the development of the Company Standards for the organizations with activities relating to the treatment of radioactive materials.
• Recommendations for the use of technical equipment and measurement methods to determine the compliance of the radioactive materials with the levels and requirements for the release from regulatory control, which are determined by the physicochemical properties of the material, the type of contamination, the radionuclide composition of the contamination established at the first stage of the release process.
• An examination of the location of the free release facility at Chernobyl NPP taking into consideration background radiation levels in the buildings and adjustment territories, available infrastructure, distances from the main storage places of materials to be cleared and development of Terms of Reference for the material clearance facility at ChNPP.
• Development of a Company Standard and regulation documents for clearance of ChNPP scrap metal:
  • STP 3.032-2016 - Procedure for Release of Radioactive Metal from Regulatory Control
  • Working Regulation “Organization of Works in a Batch of Radioactive Metal Formation before Measurements Implementation at the Facility for Release from Regulatory Control”;
  • Working Regulation “Organization of Transportation of Radioactive Metal Batch on State Specialized Enterprise “Chernobyl Power Plant” Territory”;
  • Working Regulation “Organization of Radioactive Metal Batch Control prior to Measurements at Facility for Clearance from Regulatory Control”;
  • Working Regulation “Organization of Works in Handling of Radioactive Metal Batch at Facility for Clearance from Regulatory Control”;
  • Regulation “Organization of Radioactive Metal Batch Measurements at Facility for Clearance from Regulatory Control”;
  • Regulation “Organization of Accounting of Radioactive Metal Batches and Database Keeping”;
• Development of the recommendations for the application of clearance procedures for NNEGC "Energoatom" and its operating NPPs, State Corporation “Ukrainian State Association “Radon”, uranium mining processing facilities and other facilities.
• Training of Beneficiary/End Users personnel in the form of workshops, case studies, on-job training. Transfer of know-how and experience and development of capabilities of the Beneficiary/End Users.
• Based on the results of the project implementation, the Contractor held a final workshop for a broad spectrum of representatives of the involved project stakeholders.