Optimization of gadolinium burnable poison loading by the conjugate gradients method

Thesis/Dissertation · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5860717

Drumm, C R

Improved use of burnable poison is suggested for pressurized water reactors (PWR's) to insure a sufficiently negative moderator temperature coefficient of reactivity for extended burnup cycles and low leakage refueling patterns. The use of gadolinium as a burnable poison can lead to large axial fluctuations in the power distribution through the cycle. The goal of this work is to determine the optimal axial distribution of gadolinium burnable poison in a PWR to overcome the axial fluctuations, yielding an improved power distribution. The conjugate gradients optimization method is used in this work because of the high degree of nonlinearity of the problem. The neutron diffusion and depletion equations are solved for a one-dimensional one-group core model. The state variables are the flux, the critical soluble boron concentration, and the burnup. The control variables are the number of gadolinium pins per assembly and the beginning-of-cycle gadolinium concentration, which determine the gadolinium cross section. Two separate objectives are considered: 1) to minimize the power peaking factor, which will minimize the capital cost of the plant; and 2) to maximize the cycle length, which will minimize the fuel cost for the plant. It is shown in this work that optimizing the gadolinium distribution can yield an improved power distribution.

• Research Organization: Michigan Univ., Ann Arbor (USA)
• OSTI ID: 5860717
• 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
210800 -- Nuclear Power Plants-- Economics
BURNABLE POISONS
BURNUP
DISTRIBUTION
ELEMENTS
GADOLINIUM
MATERIALS
METALS
NEUTRON ABSORBERS
NUCLEAR POISONS
PERFORMANCE
POWER DISTRIBUTION
PWR TYPE REACTORS
RARE EARTHS
REACTIVITY COEFFICIENTS
REACTOR FUELING
REACTOR MATERIALS
REACTORS
WATER COOLED REACTORS
WATER MODERATED REACTORS