Correction of rhodium detector signals for comparison to design calculations

Conference · Wed Nov 01 04:00:00 EST 1989 · Transactions of the American Nuclear Society; (United States)

OSTI ID:5420645

Judd, J L ^[1]; Chang, R Y; Gabel, C W ^[2]

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1. Idaho National Engineering Laboratory, Idaho Falls (USA)
2. Southern California Edison, Irvine (USA)

Rhodium detectors are used in many commercial pressurized water reactors PWRs (pressurized water reactor) as in-core neutron detectors. The signals from the detectors are the result of neutron absorption in {sup 103}Rh and the subsequent beta decay of {sup 104}Rh to {sup 104}Pd. The rhodium depletes {approximately}1% per full-power month, so corrections are necessary to the detector signal to account for the effects of the rhodium depletion. These corrections result from the change in detector self-shielding with rhodium burnup and the change in rhodium concentration itself. Correction for the change in rhodium concentration is done by multiplication of the factor N(t)/N{sub 0}, where N(t) is the rhodium concentration at time t and N{sub 0} is the initial rhodium concentration. The calculation of the self-shielding factor is more complicated and is presented. A self-shielding factor based on the fraction of rhodium remaining was calculated with the CASMO-3 code. The results obtained from our comparisons of predicted and measured in-core detector signals show that the CASMO-3/SIMULATE-3 code package is an effective tool for estimating pin peaking and power distributions.

• OSTI ID: 5420645
• Report Number(s): CONF-891103--
• Conference Information: Journal Name: Transactions of the American Nuclear Society; (United States) Journal Volume: 60
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
210200* -- Power Reactors
Nonbreeding
Light-Water Moderated
Nonboiling Water Cooled
440101 -- Radiation Instrumentation-- General Detectors or Monitors & Radiometric Instruments
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
BETA DECAY
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BURNUP
COMPUTER CODES
DECAY
ELECTRON CAPTURE RADIOISOTOPES
ELEMENTS
ENRICHED URANIUM REACTORS
EVEN-EVEN NUCLEI
IN CORE INSTRUMENTS
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
METALS
MINUTES LIVING RADIOISOTOPES
NEUTRON ABSORBERS
NUCLEAR DECAY
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
PALLADIUM 104
PALLADIUM ISOTOPES
PERFORMANCE
PLATINUM METALS
POWER DISTRIBUTION
POWER REACTORS
PWR TYPE REACTORS
QUANTITY RATIO
RADIOISOTOPES
REACTOR COMPONENTS
REACTOR CORES
REACTOR INSTRUMENTATION
REACTORS
RHODIUM
RHODIUM 103
RHODIUM 104
RHODIUM ISOTOPES
S CODES
SAN ONOFRE-2 REACTOR
SAN ONOFRE-3 REACTOR
SECONDS LIVING RADIOISOT
SELF-SHIELDING
SENSITIVITY
SHIELDING
STABLE ISOTOPES
THERMAL REACTORS
THREE-DIMENSIONAL CALCULATIONS
TRANSITION ELEMENTS
WATER COOLED REACTORS
WATER MODERATED REACTORS