HEATING IN CONTROL RODS FOR USE IN THE 525-Mwe SGR

Technical Report · Wed Dec 18 04:00:00 EST 1963

OSTI ID:4080863

Jackel, H E

The amounts of heat generated in a Dy/sub 2/O/sub 3/ poison rod and in two Haynes-25 poison rods were calculated at various positions along the rods and for several degrees of insertion of the rods into the core. The Dy/sub 2/O/sub 3/ rod consisted of a 0.19 in. annulus of Dy/sub 2/O/sub 3/ between a 2.12 in. diameter graphite rod, and a 2.500 in. I.D. by 0.18 in. wall HastelloyX tube. The Haynes rods were 2.84 in. OD tubes, one with a 1.00 in. wall and the other with a 0.375 in. wall, with work on the Haynes rods being concentrated upon the one with the thinner wall. Heat generation rates for gamma rays born within the poison were calculated using the GRACE-II code for various positions along rods which were 1/4, 1/2, 3/4/, and fully inserted into the core. For both rods, the peak heat generation rate occurred near the tip of the 3/4 inserted rod, and was, after the addition of decay heating, 19.6 kw/ft for the 0.375 Haynes rod and 20.9 kw/ft for the Dy/sub 2/O/sub 3/ rod. The corresponding average values were 8.9 kw/ft and 7.1 kw/ft respectively. To these values must be added the heat generated by the absorption of gamma rays born outside the rods. This was estimated to be up to 0.747 kw/ft average for the rods. These estimates were based on the heat generation in the graphite of the 525 Mw(e) ASCR. The accuracy of the Haynes calculations were estimated to be plus or minus 12%. Due to the adjustments to the results for the Dy/sub 2/O/sub 3/ rod which were necessary to obtain agreement with the calculations of leakage probabilities, the accuracy of the Dy/sub 2/O/sub 3/ results is +0% to -15%. The variation with time of the decay power for various situations was investigated and equations are given, along with some simplifications. Also investigated were the distribution of the energy originating in the rod between the rod and the moderator, and the effect of increasing the thickness of the Dy/sub 2/O/sub 3/ annulus, from 0.19 inch to 0.25 inch, on the heat generation. (auth)

• Research Organization: Atomics International. Div. of North American Aviation, Inc., Canoga Park, Calif.
• DOE Contract Number: AT(11-1)-GEN-8
• NSA Number: NSA-18-015450
• OSTI ID: 4080863
• Report Number(s): NAA-SR-Memo-9336
• Country of Publication: United States
• Language: English

Related Subjects

ABSORPTION
CHROMIUM ALLOYS
COMPUTERS
CONFIGURATION
CONTROL ELEMENTS
DECAY
DISTRIBUTION
DYSPROSIUM OXIDES
ERRORS
GAMMA RADIATION
GRAPHITE
HEATING
LEAKS
MATHEMATICS
MODERATORS
MOLYBDENUM ALLOYS
NEUTRONS
NICKEL ALLOYS
POISONING
POWER
PROGRAMMING
REACTOR CORE
REACTOR TECHNOLOGY
REACTORS
RODS
SGR
SHELLS
THICKNESS
TUBES
USES
VARIATIONS
ZONES