Breeding gain

Breathing zone measurements, 14 214, 217 Breccia complex uranium deposits, 17 520 Breeding gain (BG), 17 586 Breeding programs, to enhance allelopathy, 13 353... 

If C > 1 the possibility exists of producing more fissile material than is consumed, which is referred to as breeding. The breeding ability of a reactor is given by the breeding gain, G = rj - 2 - S. Table 19.2 shows that Pu, and Pu all have > 2 in... 

The total breeding ratio in the Creys-Malville reactor was 1.24. In BN-350 a breeding ratio of 1.5 can be obtained because it has less neutron absorbing materials. Still higher breeding gain can be achieved in fast reactors at some sacrifice of safety control. 

For an estimation of the breeding gain in thermally fissionable material, the geometry of the reactor and the pertinent nuclear constants must be considered. The following estimates have been made for the abovegeometry using reasonable values of the nuclear constants based on actual measurements ... 

Fuel residence time (efpd) Breeding Gain range -0.2 / +0.15 5x3403x285 -0,65 ... 

The predicted value is increased by 10 per cent for bulls and large breeds and reduced by 10 per cent for heifers and small breeds. Thus, the NPg of a 300 kg bull of a large breed gaining at 1.2 kg/day would be calculated as 128 X 1.10 X 1.10 X 1.20 = 186 g/day. In sheep, NPg is also calculated from hveweight but, as with energy, no account is taken of rate of gain, as follows ... 

Using the AFRC (1993) system, calculate the metabohsable energy (ME) and metabolisable protein (MP) requirements of a 300 kg bull of large breed gaining at 1.1 kg/day. Assume that the animal s diet has an M/D value of 11.0 MJ/kg DM. 

Plant Total breeding gain Breeding gain (core regions only)... 

Breeding gain is defined as BG= Wi(Ci-Di)/Fi Ci and Di - respectively rates of creation and destruction of atoms of i Wi - the worth of atoms of i, relative to atoms Fi - the total fission rate... 

A total breeding gain 1.16 was ejq)erimentally defined at the time of reprocessing of the fuel evacuated from the plant. The fuel cycle, based on mixed oxide fuel and PUREX reprocessing, has been closed and the first fuel subassembly made with reprocessed plutonium was loaded in the reactor in January 1980... 

The quantity BR — 1 is known as the breeding gain. In the absence of any contribution to the fission rate from fast fission in the fertile isotopes, 1 MW d of power operation would be provided by the fission of almost exactly 10" kg of fuel (taking the recoverable energy per fission for Pu as 215 MeV). This corresponds to 10" (1 + a) kg of fuel destroyed, where a is the capture-to-fission ratio. Taking account of the contribution to power production by fast fission of the fertile isotopes, however, the rate of destruction of fuel will be reduced in the ratio... 

Fig. 2-5. Breeding gain and critical concentration for slurry-core reactors vs. core thorium concentration. Core diameter = 6.0 ft, pressure vessel diameter - 10.0 ft, blanket thorium concentration = 1000 g/liter, blanket concentration = 3.0 g/kg of Th.

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