Physics Effects of Accidental Submersion of Space Power Reactors in Water

Conference · Mon Jan 14 04:00:00 EST 1985

OSTI ID:6181380

Bhattacharyya, S. K. ^[1]; Lell, R. M. ^[1]

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1. Argonne National Laboratory (ANL), Argonne, IL (United States)

A major safety concern for nuclear reactors in space power applications is the effect of accidental submersion of the reactors in water. Such a situation might be postulated, for example, as a consequence of a launch pad accident. The classes of reactors proposed most frequently for use in space are fast spectrum reactors, for which submersion results in a softened core neutron spectrum caused by the displacement of the liquid metal coolant by the water. The softened spectrum alters the neutron balance in the core - neutron capture and fission are increased while leakage from the core is reduced. Water outside the submerged core introduces an increased number of reflected thermalized neutrons into the core. The net effect is a function of the specific features of the reactor design (composition, size, etc.) and can be positive or negative depending upon the contributions of the individual effects. Analysis of the magnitude of the effect requires an accurate evaluation of the individual components. At present a designer must rely on detailed calculations performed after key design parameters are settled to determine the effects of submersion. The purpose of our work is to develop generic features of the submersion phenomenon to provide designers a means to an a priori knowledge of the impact of potential design choices on submersion reactivity.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 6181380
• Report Number(s): CONF-850103-5; ON: DE85005020
• Country of Publication: United States
• Language: English

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