Measurements of delayed neutron decay constants and fission yields from {sup 235}U, {sup 237}Np, {sup 241}Am, and {sup 243}Am

Journal Article · Wed Jan 01 00:00:00 EST 1997 · Nuclear Science and Engineering

OSTI ID:445402

Saleh, H H; Parish, T A ^[1]; Raman, S ^[2]; Shinohara, Nobuo ^[3]

---

1. Texas A and M Univ., College Station, TX (United States). Dept. of Nuclear Engineering
2. Oak Ridge National Lab., TN (United States)
3. Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)

Isotopes of the higher actinide elements are produced as a result of successive radiative capture reactions in the uranium fuel of nuclear reactors. Typically, these transuranic isotopes decay through long chains, have long half-lives, and dominate the long-term toxicity of spent reactor fuel. One of the options for high level waste management is to remove the higher actinide elements from spent fuel by chemical processing, to load them into new special fuel elements, and to transmute them by neutron-induced fission into shorter-lived fission fragments. Reactors designed to achieve high actinide fission (transmutation) rates are called actinide burners. In such reactors, the actinide wastes would constitute much of the fissionable fuel. Due to the high transuranic isotope loadings in the fuel of actinide burners, the neutronic properties of the higher actinide isotopes will have a significant effect on the criticality and safety characteristics of such reactors. While there is an extensive operational database for reactors fueled with uranium and plutonium, operating experience with fuel containing large amounts of actinide wastes is quite limited. Two important neutronic properties of actinide burner cores are their reactivity and their delayed neutron fraction. Both of these properties will be strongly influenced by the neutronic characteristics of the actinide waste isotopes. Here, delayed neutron yields and decay constants for {sup 235}U, {sup 237}Np, {sup 241}Am, and {sup 243}Am were measured at the Texas A and M University TRIGA reactor using a fast pneumatic transfer system. The detection system consisted of an array of BF{sub 3} proportional counters embedded in a polyethylene cylinder. The measured values of the total delayed neutron yield per 100 fissions from thermal neutron-induced fission of {sup 235}U, {sup 237}Np, {sup 241}Am, and {sup 243}Am were determined to be 1.59 {+-} 0.04, 1.29 {+-} 0.04, 0.49 {+-} 0.02, and 0.84 {+-} 0.04, respectively.

• OSTI ID: 445402
• Journal Information: Nuclear Science and Engineering, Vol. 125, Issue 1; Other Information: PBD: Jan 1997
• Country of Publication: United States
• Language: English

Related Subjects

05 NUCLEAR FUELS
22 NUCLEAR REACTOR TECHNOLOGY
ACTINIDE BURNER REACTORS
RADIOACTIVE WASTE PROCESSING
REACTOR KINETICS
HIGH-LEVEL RADIOACTIVE WASTES
URANIUM 235
NEPTUNIUM 237
AMERICIUM 241
AMERICIUM 243
DELAYED NEUTRONS
FISSION YIELD
NEUTRON REACTIONS
BF3 COUNTERS
EXPERIMENTAL DATA
COMPARATIVE EVALUATIONS