Concept of a fast breeder reactor to transmute MAs and LLFPs

The long-term issues of nuclear power systems are the effective use of uranium resources and the reduction of radioactive waste. Important radioactive wastes are minor actinides (MAs: 237Np, 241Am, 243Am, etc.) and long-lived fission products (LLFPs: 129I, 99Tc, 79Se, etc.). The purpose of this study was to show a concept that can simultaneously achieve the breeding of fissile materials and the transmutation of MAs and LLFPs in one fast reactor. Transmutation was carried out by loading innovative Duplex-type MA fuel in the core region and LLFP-containing moderator in the first layer of the radial blanket. Breeding was achieved in the core and axial blanket. As a result, it was clarified that in this fast breeder reactor, a breeding ratio of approximately 1.1 was obtained, and MAs and LLFPs achieved a support ratio of 1 or more. The transmutation rate was 10.3%/y for 237Np, 14.1%/y for 241Am, 9.9%/y for 243Am, 1.6%/y for 129I, 0.75%/y for 99Tc, and 4%/y for 79Se. By simultaneously breeding fissile materials and transmuting MAs and LLFPs in one fast reactor, it will be possible to solve the long-term issues of the nuclear power reactor system, such as securing nuclear fuel resources and reducing radioactive waste.

Optimisation of helical geometry of inspection probe for steam generator tubes of the PFBR

The steam generator (SG) tubes of the prototype fast breeder reactor (PFBR) located in Kalpakkam, India, need to be periodically inspected using the remote field eddy current (RFEC) technique. During the pre-service inspection of the SG tubes, it was found that the RFEC probes experienced frequent mechanical breakages. To avoid these failures, changes in the existing structural design of the RFEC probe were required. A helical groove design was proposed to obtain a smooth transition in the variation of stress across the probe during the inspection. It was difficult to calculate the flexural stiffness of the proposed helical geometry probe due to the varying cross-section along its length. In this paper, the smearing approach adopted to calculate the stiffness of the RFEC probe and the sensitivity analysis carried out to determine the optimal design of the probe are discussed. A probe was fabricated based on the helical groove design and tested to qualify its suitability for the SG inspection. The RFEC probe with helical grooves was employed for the pre-service inspection of the SG tubes of the PFBR. More than 200 tubes have been inspected using the proposed design and no mechanical failure of the probe has been observed.

Numerical Investigation of Fluid – Structure Interaction (FSI) on Sodium Leakage Accident at Prototype Fast Breeder Reactor Monju

This study presents a numerical investigation of fluid-structure interaction about sodium leakage accident at prototype fast breeder reactor Monju. The dynamic forces of sodium liquid flow acting on the thermowell are the main cause of fatigue failure, which leads to the occurrence of thermowell cracking due to intense stresses and high fatigue-cycle. Since the location and magnitude of these stresses are unknown, an analysis of the vibrational characteristics and stresses caused by FSI was performed by using ANSYS to prevent similar accidents in the future. The most dangerous case was found for FSI analysis by comparisons between the natural frequency of thermowell and vortex shedding frequency at several operating conditions. The results showed that a stress concentration location is similar to the location of broken thermowell, and the amplitude of stress is large enough for fatigue damage.

Concept of a Fast Breeder Reactor To Transmute MA and LLFP

The long-term issues of nuclear power systems are the effective use of uranium resources and the reduction of radioactive waste. Important radioactive wastes are minor actinides (MA: 237 Np, 241 Am, 243 Am, etc.) and long-lived fission products (LLFP: 129 I, 99 Tc, 79 Se, etc.). The purpose of this study was to show a system that can simultaneously achieve the breeding of fissile materials and the transmutation of MA and LLFP in one fast reactor. Transmutation was carried out by loading innovative Duplex type MA fuel in the core region and LLFP containing moderator in the first layer of the radial blanket. Breeding was achieved in the core and axial blanket. As a result, it was clarified that in this fast breeder reactor, a breeding ratio of about 1.1 was obtained, and MA and LLFP achieved a support ratio of 1 or more. The transmutation rate was 10.3%/y for 237 Np, 14.1%/y for 241 Am, 9.9%/y for 243 Am, 1.6%/y for 129 I, 0.75%/y for 99 Tc, and 4%/y for 79 Se. By simultaneously breeding fissile materials and transmuting MA and LLFP in one fast reactor, it will be possible to solve the long-term issues of the nuclear power reactor system, such as securing nuclear fuel resources and reducing radioactive waste.

Dounreay: Creating the Nuclear North

This article combines the traditionally rural focus of Highland history with the growing field of nuclear culture to examine the impact which Dounreay Experimental Research Establishment had on Caithness between 1953 and 1966. From the outset of the project the United Kingdom Atomic Energy Authority knew that it would have to import specialist technical staff into an area economically driven by agriculture and fishing. This resulted in a distinct form of employment-based migration to the Highlands, reversing population decline in Caithness during the period of study. This article identifies the reasons for, and local reaction to, the UKAEA's choice of Caithness as the location for its fast breeder reactor establishment. It assesses the significant in-migration to the area during the initial phase of the Dounreay plant's development, before exploring how perceptions of distance and Caithnessian ‘difference’ affected the recruitment of staff in what the UKAEA considered an ‘unconventional’ location. It puts people and place at the centre of the nuclear project, revealing Dounreay's role in creating a mid-twentieth century Highland counter-narrative of in-migration and modernity far removed from traditional discourses of depopulation.

Local and global trace plutonium contributions in fast breeder legacy soils

Trace-level plutonium in the environment often comprises local and global contributions, and is usually anthropogenic in origin. Here, we report estimates of local and global contributions to trace-level plutonium in soil from a former, fast-breeder reactor site. The measured 240Pu/239Pu ratio is anomalously low, as per the reduced 240Pu yield expected in plutonium bred with fast neutrons. Anomalies in plutonium concentration and isotopic ratio suggest forensic insight into specific activities on site, such as clean-up or structural change. Local and global 239Pu contributions on-site are estimated at (34 ± 1)% and (66 ± 3)%, respectively, with mass concentrations of (183 ± 6) fg g−1 and (362 ± 13) fg g−1. The latter is consistent with levels at undisturbed and distant sites, (384 ± 44) fg g−1, where no local contribution is expected. The 240Pu/239Pu ratio for site-derived material is estimated at 0.05 ± 0.04. Our study demonstrates the multi-faceted potential of trace plutonium assay to inform clean-up strategies of fast breeder legacies.