Neutron Yield from the (α, n) Reaction in the Isotope Oxygen-18

Neutron Radiation Characteristics of Plutonium Dioxide Fuel

“…Since the maximum energy of neutrons from 18 O (a, n) is about 4.5 meV and only 12% of the neutrons were estimated to be due to (a, n) reactions with impurities, 2 the 2 From a nonrelativistic two-body reaction and by using 5. Pu) assumption that beyond 5 MeV nearly all the neutrons are from spontaneous emission was justified and, therefore Eq.…”

“…The analysis of this interaction is given elsewhere (Refs. 13,18,19). In this section, the result of such a calculation is analyzed in terms of the total neutron yield.…”

“…If all the contributing impurities are removed and the 18 O isotope is left in the fuel, the total neutron yield spectrum will be equal to the sum of the spontaneous fission yield and the (a, n) reaction with oxygen. Such a result is presented in Table 10, where the computed results and the measured values reported by the Los Alamos group (Ref.…”

“…These sources include spontaneous fission of several of the Pu isotopes, (a, n) reactions with low Z impurities in the fuel, and (a, n) reactions with 18 O. For spontaneous fission neutrons a value of (1.95 ±0.07) X 10 3 n/s/g PuO* is obtained.…”

“…Neutron yield due to (a,n) reactions with impurities in a 238 Pu heat source ... 2. Weighted neutron yield from 18 …”