ARMY PACKAGE POWER REACTOR PROJECT ANNUAL PROGRESS REPORT FOR PERIOD ENDING JANUARY 31, 1960

Technical Report · Fri Apr 01 04:00:00 EST 1960

OSTI ID:4173656

BS>Nuclear calculations were performed to investigate the burnout behavior of 10,000-Mwd/ton Pu when used as the fuel for an SM-1 reactor. The reactivity lifetime curve was found to be relatively flat compared with that for the reactor fueled with U plus B burnable poison. The magnitude of B losses incurred during fabrication of SM-1 core I fuel plates was determined by chemical analyses of 18 fuel plates remaining from core I manufacturing. Results of analyses indicated that the average boron loss in core I fuel plates was 22.4%. Fabrication procedures were developed for incorporating a dispersion of 26 wt.% Eu/sub 2/O/sub 3/ in elemental type 304 stainless steel directly at the end of the fuel-bearing section of a control rod fuel plate. Eight full-size control rod fuel elements containing Eu/sub 2/O/sub 3/ internal flux suppressors were manufactared for service in core II of the SM-1 reactor. Studies to determine the mechanism of B losses from boron-stsinless steel alloys during high- temperature heat treatment were continued. These studies led to a mechanistic hypothesis in which O has an important role. A loss theory is outlined in which B is converted to B/sub 2/O/sub 3/, which may then volatilize or react with any available moisture to form more volatile B compounds. The corapatibility of zirconium diboride, boron nitride, boron carbide, and strontium hexaboride with type 304LB stainless steel was investigated. It was concluded that the selected compounds were unstable at the temperatares and times considered. SpecificatLons and fabrication procedures were established for Eu/sub 2/O/sub 2/-bearing control rods for the SM-1 reactor. Eight absorber sections containing a homogeneous dispersion of 37 wt.% Eu/sub 2/O/sub 3/ in type 304 stainless steel were fabricated for core II of the SM-1 reactor. Exploratory studies were initiated to evaluate more closely the effect of silicon on the chemical stability of Eu/ sub 2/O/sub 3/ in type 304 stainless steel. Mechanical properties of dispersions of mixed rare earth oxides in stainless steel were measured as a junction of temperature for 30 and 50 wt.% oxide dispersions. Fabrication studies were initiated toward development of a B gradient control rod. Long-term corrosion tests or brazed joints and of defective fuel plates in high-temperature water were completed. Preliminary short-term corrosion tests were conducted in which deliberately defected Eu/sub 2/O/sub 3/ specimens were exposed to high- temperature water. No dimensional changes were noted, but there was a leaching of the exposed Eu/sub 2/O/sub 3/ particles. A postirradiation examination was made on SM-1 reactor core I fuel elements and absorber sections which had operated for 10.5 Mw yr. Although there had been no apparent operational difficulties, visual examination during a scheduled maintenance shutdown revealed what appeared to be a number of structural failures. Detailed examination of two absorber elements showed loss of core-clad bonding at the high-flux end of seven of the eight plates of the two assemblies, clad-frame separation in five plates, and clad failures in two plates. Two fuel elements (one stationary and one fuel element control rod) were examined, and no evidence of cracking was noted. Although a number of suspected cracks were reported in the preliminary examination, these suspect areas were found to be only superficial scratches. An analytical approach led to formulation of a theory of irradiation damage in UO/ sub 2/stainless steel dispersion fuels. (For preceding period see ORNL-2703.) (auth)

• Research Organization: Oak Ridge National Lab., Tenn.
• DOE Contract Number: W-7405-ENG-26
• NSA Number: NSA-14-013477
• OSTI ID: 4173656
• Report Number(s): ORNL-2907
• Country of Publication: United States
• Language: English

Related Subjects

BONDING
BORIDES
BORON
BORON COMPOUNDS
BORON NITRIDES
BRAZING
BURNOUT
CHEMICAL REACTIONS
CONTROL ELEMENTS
CORROSION
DEFECTS
DEFORMATION
DISPERSIONS
EQUATIONS
EUROPIUM OXIDES
FABRICATION
FAILURES
FUEL ELEMENTS
HEAT TREATMENTS
HIGH TEMPERATURE
JOINTS
LIFETIME
LOSSES
MECHANICAL PROPERTIES
NUCLEAR REACTIONS
OXIDES
OXYGEN
PLATES
PLUTONIUM
POISONING
POWER PLANTS
QUALITATIVE ANALYSIS
RADIATION EFFECTS
RARE EARTHS
REACTIVITY
REACTOR TECHNOLOGY
REACTORS
SILICON
SM-1
STABILITY
STAINLESS STEELS
STRONTIUM BORIDES
TEMPERATURE
URANIUM DIOXIDE
VARIATIONS
VOLATILITY
WATER COOLANT
ZIRCONIUM BORIDES