Neutron and Beta/Gamma Radiolysis of Supercritical Water

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Neutron and Beta/Gamma Radiolysis of
Supercritical Water

• NERI Project 02-060
• Argonne National Laboratory
• David Bartels
• Chuck Jonah
• University of Wisconsin
• Paul Wilson
• Mark Anderson
• Robert Agasie

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How much Oxygen and Hydrogen Peroxide is produced
in the radiolysis of supercritical water at
various temperatures and pressures??? Can
radiolysis be suppressed by adding hydrogen?
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Water Properties
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Microheterogeneity
Tucker, S.C. and Maddox, M.W., J.Phys. Chem. B,
1998, 102, 2437.
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Electron Radiolysis
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Neutron Radiolysis
fast ion
H2O H2, O2, H2O2, HO2., OH, H, (e-)aq
in reactor, use H2 OH H H2O H
H2O2 H2O OH H O2 HO2. etc.
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Reaction Set for Radiolysis of Water
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Apparatus for Supercritical Water Radiolysis
Studies
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Optical Cell for Supercritical Water Radiolysis
Sapphire windows
2 cm
Spring washers
Gold Gaskets
Electron Beam Access
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Sample Kinetics Data --O2 Reaction with (e-)aq
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Hydrated Electron Reaction with Oxygen
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Density dependence of several reactions at 380C
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Ratio of H atoms to electrons formed in radiolysis
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Reaction of OH Radical with H2
Why should this simple reaction slow down at
higher temperature?
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Data from NRU Reactor U-2 Loop experiment,
showing slow decrease of hydrogen as it was
titrated with a slow addition of oxygen, until
the sudden onset of radiolysis indicated by the
rapid appearance of oxygen (from Elliot et al.
1997). The slight mismatch in stoichiometry
between the oxygen and hydrogen arises from
instrument calibration errors, and/or loss of
oxygen on pipework. The latter was frequently
observed. The temperature at the reactor outlet
was 307.5C.
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University of WisconsinSupercritical Water
Neutron Radiolysis Loop