CONTROL ROD CALIBRATIONS FOR THE SRE WITH THORIUM-URANIUM FUEL

Technical Report · Fri Jun 01 04:00:00 EDT 1962

OSTI ID:4823214

Keaten, R W; Lewis, R A

Shim and safety rods of the Sodium Reactor Experiment were calibrated for the second core loading of thoriumuranium fuel clusters. One shim rod was differentially calibrated by period measurements, using two different configurations of the other rods to permit an estimation of the shadowing effect between rods. The other rods were then calibrated by comparing them to this rod. Results showed that the average rod worth had increased about 14% of the rod worth above that in the first core. A calculation gave results in good agreement, and showed that the increase was caused by an increase in the thermal diffusion area. The total measured worth of the control system was .0 plus or minus 0.7, but analysis indlcated that shadowing between rods reduced this to plus or minus 2. The shutdown margin with the operational loading was thus plus or minus 2. Calculations showed that loss of shim rod worth due to burnup was less than 20C for the combined first and second core operation. Complete burnup would require over 100,000 Mwd. However, the rods must be recalibrated every 2000 Mwd because the change in critical configuration due to fuel burnup causes a change in the calibration curves. Subsidiary measurements showed that the theoretical waiting times of B. J. Toppel were accurate, and that use of O. Riedel's statistical method permitted a precision of 1% in the period measurements. (auth)

• Research Organization: Atomics International. Div. of North American Aviation, Inc., Canoga Park, Calif.
• DOE Contract Number: AT(11-1)-GEN-8
• NSA Number: NSA-16-026597
• OSTI ID: 4823214
• Report Number(s): NAA-SR-6585
• Country of Publication: United States
• Language: English

Related Subjects

BURNUP
CONTROL ELEMENTS
DIFFUSION LENGTH
EQUATIONS
FUEL ELEMENTS
FUELS
LIQUID METAL COOLANT
MEASURED VALUES
NEUTRONS
POWER PLANTS
REACTIVITY
REACTOR TECHNOLOGY
REACTORS
SODIUM
SRE
STANDARDS
STATISTICS
THORIUM
URANIUM
VARIATIONS