SELF-LIMITING POWER EXCURSION TESTS OF A WATER-MODERATED LOW-ENRICHMENT UO$sub 2$ CORE IN SPERT I

Technical Report · Wed Feb 28 00:00:00 EST 1962

OSTI ID:4792227

Spano, A H; Barry, J E; Stephan, L A; Young, J C

The results of a Spert I experimental investigation of the dynamic behavior of a heterogeneous, light-watermoderated reactor, employing low- enrichment UO/sub 2/ rodtype fuel elements are presented. Self-limiting power excursion tests, initiated by step insertions of reactivity, were conducted over a wide range of initial asymptotic reactor periods, from 30 sec to 3.2 msec. In the long-period region, reactor shutdown was provided both by the various heat- transfer-dependent mechanisms effecting loss of moderator from the core and by Doppler broadening of the where the reactor period was small compared to the thermal time constant of the UO/sub 2/ fuel rods, reactor shutdown was provided essentially by the Doppler reactivity effect alone, which permitted a direct measurement of the dynamic Doppler coefficient of the core. An additional reactivity effect, positive in sign and arising as a result of the systematic bowing of the fuel rods during the transient power burst, was observed to introduce a significant change in burst shape behavior. Separation of this fuel rod bowing effect from other reactivity feedback effects was obtained by performing two series of reactor transient experiments: one in which fuel rod bowing occurred and the other in which bowing was effectively suppressed by mechanically constraining the fuel rods. The shortest asymptotic reactor period test performed was a 3.2-msec test, wherein the maximum power reached was about 7500 Mw, the total nuclear energy released in the transient was about 107 Mwsec, and the maximum steam pressure developed was about 8 psi. No damage occurred as a consequence of this test. (auth)

• Research Organization: Phillips Petroleum Co. Atomic Energy Div., Idaho Falls, Idaho
• DOE Contract Number: AT(10-1)-205
• NSA Number: NSA-16-015782
• OSTI ID: 4792227
• Report Number(s): IDO-16751
• Resource Relation: Other Information: Orig. Receipt Date: 31-DEC-62
• Country of Publication: United States
• Language: English

Related Subjects

REACTOR TECHNOLOGY
ABSORPTION
DEFORMATION
DOPPLER EFFECT
EXCURSIONS
FAILURES
FUEL ELEMENTS
HEAT TRANSFER
LOSSES
MECHANICAL STRUCTURES
POWER
PRESSURE
REACTIVITY
REACTOR CORE
REACTOR KINETICS
REACTOR SAFETY
RESEARCH REACTORS
RESONANCE ESCAPE PROBABILITY
RODS
SHUTDOWN
SPECTRAL SHIFT
SPERT-1
STEAM
TESTING
TRANSFER FUNCTIONS
TRANSIENTS
URANIUM 238
URANIUM DIOXIDE
VARIATIONS
WATER MODERATOR