Potential Eutectic Failure Mechanism for Stainless Steel Cans Containing Plutonium Metal
Summary:
Plutonium and iron are known to form a eutectic at
a relatively low temperature, i.e., ˜ 400-410°C.
A study has been conducted to assess the likelihood that
the Pu/Fe eutectic reaction acts as a failure mechanism
for stainless steel cans containing plutonium metal. The
study consisted of a review of the metallurgical data
obtained from diffusion couples and irradiated Pu-bearing
metallic fuels, and a thermal analysis of Model 9975 packaging
containing Pu metal in a stainless-steel can under a postulated
fire scenario in a storage facility, i.e., 800°C for
4 hours.
The results of the study show that even in a 800°C
fire with a duration of up to 4 hours, the Model 9975
packaging would provide adequate thermal protection, and
the 3013 can temperature would stay significantly below
the Pu/Fe eutectic temperature of ˜ 400-410°C.
Indeed, even if the 3013 can reaches 400°C, the kinetics
of the reaction is such that the walls of the 3013 can
may survive several days at that temperature. Above 400°C,
the progression depends strongly on the peak temperature
and duration, as well as the thermal performance of the
protective packaging. For facilities that store Pu metals
in 3013 cans, whether bare, in Model 9975, and/or in other
packagings, a review of the documented safety analysis
should be performed, with special attention paid to the
fire event. Compensatory measures should be taken, if
deemed necessary.
Format:
Pages :14
Size: 510 kb
Author :Hanchung Tsai, Yung Liu, Allen Smith,Nick Gupta,
and Steve Bellamy
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