ENVIRONMENTAL INFLUENCES ON FUEL BURNUP IN MK. III GCR'S: PART I. EQUILIBRIUM SITUATION (CONTINUED). PART II. EFFECTS OF CONTROL RODS.
This note studies the properties of fuel in two particular reactor situations. The first part (a continuation of a previous note) simulates an area of an equilibrium HTR core by a non-leaking supercell. Comparisons are made between these results and the zero-leakage edit of the corresponding WIMS output.Environmental effects, in the form of 9-group bucklings as a function of irradiation, are derived from the supercells and used to constrain a further WIMS burnup. It is found that the changes in characteristics between these two runs are significant at any point in time, but small when averaged over life. The recycled data is then put into the supercells and the change observed is insignificant. The second part investigates fuel close to a grey control rod. A cylindrical supercell model is used and gives a hardened spectrum near the rod, which is reflected in a considerable change of properties of the fuel. It appears that a 2-group calculation is incapable of representing this situation adequately. Bucklings for the rodded block are then put into WIMS and an appreciable change in fuel properties is observed. It is also found that rod-worth varies considerably with the irradiation of adjacent fuel, and that the error in using unrecycled data to predict this is significant. It is estimated that a simple 2-group recycle should be adequate for many purposes. (auth)
- Research Organization:
- Central Electricity Generating Board, Berkeley (England). Berkeley Nuclear Labs. (United Kingdom)
- NSA Number:
- NSA-24-031069
- OSTI ID:
- 4138746
- Report Number(s):
- RD/B/N-1550; M-3-RPC/P-101
- Country of Publication:
- United Kingdom
- Language:
- English
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BURNUP
CONFIGURATION
CONTROL ELEMENTS
FUELS
GAS COOLED REACTORS
HTGR TYPE REACTORS
PERFORMANCE
POWER REACTORS
REACTOR CORE
REACTORS
GAS-COOLED/fuel burnup in Mark 3
effects of core configuration and core management on
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REACTOR FUELS/burnup of Mark 3 gas cooled
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