Studies on physics parameters of metal (U–Pu–Zr) fuelled FBR cores

Materials science research for sodium cooled fast reactors

“…Addition of zirconium has two objectives: (i) to increase the solidus temperature of the fuel and (ii) to inhibit the inter diffusion of the clad components, Fe, Ni etc and the fuel constituents, U, Pu, fission products etc which could lead to the formation of low melting eutectic alloys. Studies carried out at IGCAR on U-Pu-Zr alloys with varying Zr contents (Riyas and Mohanakrishnan 2008) have shown that BR increases with reducing Zr content. Hence it is proposed to optimize the zirconium contents (6% or lower values) using test irradiations in FBTR so that higher breeding can be ensured.…”

An investigation on Unprotected Loss of Flow Accident in Th–Pu metal fuelled 500 MWe fast reactor

“…Since the previous study (Stephen and Reddy, 2013) considered wide range of fuel types, the excess reactivity limit was 4700 pcm, i.e., k eff $ 1.047. For the sake of comparison with U-Pu-6Zr metal fuel core of 500 MWe capacity, the excess reactivity in the present study is taken as 5000 pcm with Monte Carlo simulations (cold critical condition), which also happens to be the excess reactivity of the reference core (Riyas and Mohanakrishnan, 2008;Sathiyasheela et al, 2011). Therefore enrichment of the core 1 region is increased from 18.8% (Stephen and Reddy, 2013) to 19.3%.…”

“…For metal reactors, since control rod worth requirements are low, UTOPA accidents are less severe (Cahalan et al, 1990). But in medium and large sized metal reactors, especially with U-Pu-6Zr fuel type, the principal concern is its large sodium void coefficient and reduced Doppler effect (Yokoyama et al, 2005;Riyas and Mohanakrishnan, 2008;Stephen and Reddy, 2013). In a situation where there is an uncontrolled insertion of positive reactivity, fast reactors rely on temperature related negative reactivity feedbacks to attain another steady state.…”

“…Future of the expanded nuclear power industry of Fast Breeder Reactors (FBRs) depends critically on the choice of fuel cycle, especially a fuel type which has the potential for high breeding so that doubling time is shorter. Therefore the development of metal fuel reactors has been recognized (Baldev Raj et al, 2005;Chetal, 2009) and metal FBR cores having various sizes have been designed to study their neutronics characteristics (Devan et al, 2011;Riyas and Mohanakrishnan, 2008). Harder neutron spectrum due to the absence of lighter atoms in metal reactors increases breeding ratio.…”

Fabrication and evaluation of rare-earth-bearing fuel slugs for sodium-cooled fast reactors

“…Metallic fuels have many advantages such as simple fabrication procedures, good neutron economy, high thermal conductivity, excellent compatibility with Na coolants, and inherent passive safety and thus, they are considered as one of the candidate fuels for SFRs [4][5][6][7][8][9][10][11]. The favorable properties of metallic fuels have led to the development of uranium-zirconium fuel elements for use in SFRs; e.g., U-10 wt%Zr was used in the EBR II reactor, USA, in the early 1985 [11].…”