Evolution of the collective radiation dose of nuclear reactors from the 2nd through to the 3rd generation and 4th generation sodium-cooled fast reactors

Joel Guidez,Anne Saturnin

doi:10.1051/epjn/2017024

Abstract

During the operation of a nuclear reactor, the external individual doses received by the personnel are measured and recorded, in conformity with the regulations in force. The sum of these measurements enables an evaluation of the annual collective dose expressed in man·Sv/year. This information is a useful tool when comparing the different design types and reactors. This article discusses the evolution of the collective dose for several types of reactors, mainly based on publications from the NEA and the IAEA.The spread of good practices (optimization of working conditions and of the organization, sharing of lessons learned, etc.) and ongoing improvements in reactor design have meant that over time, the doses of various origins received by the personnel have decreased.In the case of sodium-cooled fast reactors (SFRs), the compilation and summarizing of various documentary resources has enabled them to be situated and compared to other types of reactors of the second and third generations (respectively pressurized water reactors in operation and EPR under construction). From these results, it can be seen that the doses received during the operation of SFR are significantly lower for this type of reactor.

Highlights

Since 1992, the Information System on Occupational Exposure (ISOE) program, supported by the OECD/NEA and the IAEA, has collected and analyzed data concerning the radiological exposure of personnel working in nuclear power plants
To ensure such a low radioactivity, biological shields surround the core and even the lower parts of the heat exchangers [18]. This type of reactor design has potential for collective dose reductions compared to the pressurized water reactors (PWRs)/boiling water reactors (BWRs). To maintain this potential advantage in terms of radiation protection, the design of future sodium-cooled fast reactors (SFRs) reactors will need to integrate a certain number of options enabling dose minimization right from the earliest phases: pool-type design with the intermediate heat exchangers located within the main vessel, non-activated secondary circuits, tritium trapping in cold traps, remote handling in liquid sodium, cleaning pits enabling component decontamination, etc
It was interesting to collect several international and available results in order to compare their order of magnitude with collective doses for other types of reactors in spite of the differences

Summary

Introduction

Since 1992, the Information System on Occupational Exposure (ISOE) program, supported by the OECD/NEA and the IAEA, has collected and analyzed data concerning the radiological exposure of personnel working in nuclear power plants. The electricity producers and national regulatory authorities of around 30 countries participate in this network, which includes 90% of the commercial nuclear power reactors in the world (400 operating reactors and 80 shutdown reactors). The ISOE draws up lists of the collective dose for the different types of reactors [1,2]. The dose rates for sodium-cooled fast reactors (SFRs), as well as for other facilities in the fuel cycle, have not been assessed by the ISOE program. At Marcoule, the CEA has gathered information published in the literature in order to develop a specific database giving additional information.

Causes of irradiation during the operation of a reactor

Comparative analysis of PWRs and SFRs

Findings

Conclusion