A CRITICAL EXAMINATION OF THE UNCERTAINTIES IN PREDICTED GROSS FISSION PRODUCT POISONING

Technical Report · Thu Mar 01 04:00:00 EST 1962

OSTI ID:4827833

Hansen, E C

To predict correctly the lifetime of the highly enriched, pressurized water reactors, an accurate estimation of the gross fission product poisoning during and through core life is required. In addition, a knowledge of the uncertainty associated with the predicted gross poisoning is necessary. The sources of error in the predicted gross poisoning are listed. The detailed examination of errors introduced by the uncertainties in the experimental data upon which the caIculations rest and by the assumption that the stable fission products are formed directly in fission is described. When the total thermal poisoning is expressed as a 2200 m/sec absorption cross section with the units barns/fission, its standard deviation is 3% essentially independent of fuel depletion, moderator temperature, and neutron flux spectrum. When the total resonance poisoning is expressed as a resonance integral with the units barns/ fission, its standard deviation is 7% essentially independent of fuel depletion, moderator temperature, and neutron flux spectrum. The error introduced in the predictron of the gross fission product poisoning by the assumption that the stable fission products are formed directly in fission can be significant. However the lack of knowledge of the 2200 m/sec absorption cross sections and resonance integrals of the radioactive precursors and the necessity of specifying a power history prevents any statement being made quantifying the error introduced in any particular calculation. It can be concluded though that for any critical calculation of a lifetime of a specified system the gross fission product poisoning would have to be calculated properly accounting for the power history of the system and the holdup of the stable fission products during the time required for their radioactive precursors to decay. (auth)

• Research Organization: Knolls Atomic Power Lab., Schenectady, N.Y.
• DOE Contract Number: W-31-109-ENG-52
• NSA Number: NSA-16-021814
• OSTI ID: 4827833
• Report Number(s): KAPL-M-ECH-8
• Country of Publication: United States
• Language: English

Related Subjects

ABSORPTION
CROSS SECTIONS
EQUATIONS
ERRORS
FISSION PRODUCTS
LIFETIME
MODERATORS
NEUTRON FLUX
NEUTRONS
POISONING
POWER PLANTS
PRESSURE
REACTOR TECHNOLOGY
REACTORS
RESONANCE ESCAPE PROBABILITY
RESONANCE NEUTRONS
SPECTRA
TEMPERATURE
WATER COOLANT