Radiation in Nuclear Fuel Cycle
Investigation of the Radiation in Nuclear Fuel Cycle Based on Reprocessed Uranium and Mixed Uranium-Plutonium Fuel
Tech Area / Field
- FIR-FUC/Fuel Cycle/Fission Reactors
8 Project completed
Senior Project Manager
Genisaretskaya S V
All-Russian Scientific Research Institute of Non-Organic Materials named after A. Bochvar, Russia, Moscow
- Electrostalsky Machine Building Plant (EMZ), Russia, Moscow reg., Elektrostal\nKurchatov Research Center / Institute of Nuclear Reactors, Russia, Moscow
- Oak Ridge National Laboratory, USA, TN, Oak Ridge
Project summaryIn 1995–1997 in line with the ISTC Project # 273-95 radiation conditions resulted from fabricating RU fuel (for VVER-440, VVER-1000 and RBMK-1000) and MOX fuel (for VVER-1000) were analyzed.
The outcome of the Project # 273-95 is as follows:
- the approach developed to predict radiation conditions from fabricating various nuclear fuels of different radiological properties;
- the isotopic composition of natural U fuel, RU fuel and MOX fuel for the VVER-440, VVER-1000 and RBMK-1000 reactors calculated as a function of burnup, initial enrichment, storage time of unirradiated fuel and cooling time of spent fuel;
- preliminary comparison study of the calculated and measured data on the isotopic content for VVER-440 and RBMK-1000 spent fuels (including that of 232U, 236Pu et.). For the most part the agreement is satisfactory but inadequate in specific cases and requires further research;
- calculated radiation conditions with RU instead of natural U and in fabricating R-Pu or W-Pu-based MOX fuel in terms of models chosen for specific fabrication process.
The study has shown that:
1. At the earliest stage during the R&D phases of the fuel production the radiation conditions can be calculated from radiation fields on the basis of the fuel isotopic composition in terms of the content of radiationally-hazardous isotopes (232U, 236Pu, etc.).
2. Radiation conditions prediction offers a means of:
- justifying the fuel fabrication safety;
- comparing radiation conditions for various fuel fabrication practices and feeds;
- placing limitations on the content of hazardous nuclides in the feed and fuel;
- providing initial data for designing fuel fabrication facilities and optimizing the shielding;
- making the best choice of nuclear fuel cycle options based on reprocessed feed;
- characterization of radioactive waste.
3. More correct estimates of occupational radiation exposure to substantiate the safety of a RU or MOX fabrication process invite further research for the purpose of making the calculation of on-site - and neutron radiation fields and of the isotopic content of various fuel types more precise.
These circumstances provided the basis for making out a Project Extension Proposal. The Proposal incorporates experimentation and further calculation to make the prediction more precise and its demonstration. The demonstration will be conducted in the Russian leading fuel fabrication plant (EMBP).
The work will involve:
1. Study of radiological characteristics of RU and MOX by calculations and measurements.
2. Calculations of VVER-440, VVER-1000 and RBMK-1000 spent fuel isotopic compositions (including 232U, 236Pu, isotopes of Am and of Cm) in samples and check against experimental data.
3. Calculation of radiation conditions during fabrication of actual VVER-440 and RBMK-1000 fuels and comparison between predicted and measured data.
Preliminary agreement is reached concerning the participation of foreign collaborators to correct and compare the procedure and programmes to be used. The collaborator's concern is confirmed by Minutes of the Meeting between BNFL, JRC-ITU and VNIINM held in Risley, UK, April, 1997.
The resulting information will be given in VNIINM’s Final Report and INR RRC KI’s Stage 2 Progress Report. The reports will cover:
- results of a comparative analysis of calculated and measured radiation fields to check the calculation for accuracy; recommendations for codes used for on-site predictions;
- results of a comparative analysis of estimated and measured isotopic compositions to check the hazardous nuclide content estimates for accuracy;
- radiation conditions estimates for a primary U and RU fuel fabrication plant in operation.
In the end, the Proposal will provide an improved procedure for estimating the fuel fabrication radiation conditions. Its large-scale demonstration will offer results of commercial use for:
- developing and implementing the utilization of spent fuels and Pu in energy-producing reactors in operation;
- making the best choice of RU and MOX fuel compositions;
- affording radiation safety of fuel production both new and existing.