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Studies on the impact of I and Cs on the Pb-Bi liquid-metal system. Introduction. Objective - to experimentally determine the impact of I and Cs on Pb-Bi liquid metal. And at the same time see which quantities of which substances could arise as vapours and where they deposit.
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Studies on the impact of I and Cs on the Pb-Bi liquid-metal system
Introduction • Objective - to experimentally determine the impact of I and Cs on Pb-Bi liquid metal. And at the same time see which quantities of which substances could arise as vapours and where they deposit. • Experiments were executed at FZK
Overview • Reiterate results from experiments at 400/600/700C. • Results from experiments at 800 and 900C • Conclusions
Test setup at 400/600/700C • Heating causes the Pb-Bi to melt • Further heating causes the Pb membrane to melt • The steel crucible is flushed with inert gas (Ar), which passes through two serially connected gas washing bottles
Test setup at 800/900C • Argon gas carries I into the melt • After experiment the wash bottle and Pb-Bi was analyzed
Temperature logging at 800C T2 T1 T5 T4
Tests performed at 800/900C *substances wt.%
Conclusions 400/600/700C • The tests up to 600ºC indicates that I, CsI, and Cs remain in the Pb-Bi and probably form lead iodide and bismuth iodide. Cs probably forms intermetallic compounds with Pb and Bi. • No removal of I nor Cs by gas phase was found. • Because of experimental limitations, no demonstration of I retention at 600 ºC was possible.
Conclusions 800/900C • Neither I nor Cs were found in the gas wash bottles • I and Cs deposited on colder regions (capsule lid) • Structural examination did not reveal any inclusions in the solidified melts except for I-800C which showed oxidic inclusions in the region close to the surface • For the Cs experiments it is assumed that part of the cesium was dissolved in the melt (borne by the alkaline reaction of the melt)
Planned tests • More experiments are planned NRG in the hot cells of the HFR. A fuel pellet shall be melted. And it would be covered by Pb. All volatile fission products would be investigated.