IN-REACTOR MONITORING OF ZIRCALOY-2 PRTR PRESSURE TUBES. PART I. SEPTEMBER 1960-MAY 1962

Technical Report · Tue May 01 04:00:00 EDT 1962

OSTI ID:4798659

Doman, D R; Pankaskie, P J

Remotely operable experimental equipment was developed and used in the PRTR for: visually examining the internal surface of the pressure tubes, measuring the inside diameters of the pressure tubes, measuring the eccentricity of the heliunm gas annulus between the Zircaloy-2 pressure tube and aluminum shroud tube, and measuring the depth of wear corrosion atiack, mechanical gouges, defects, etc. The monitoring schedule is based on the concept of inspecting one- half of the tubes at least twice within 14 reactor operating periods. Under this schedule, two tubes from each of three alternate sextants of the reactor are inspected at the end of each ten day reactor operating period. Repeat inspections are normally made after three and before seven consecutive operating periods. Provisions are made to inspect and tube in which a fuel element failure has occurred. To date eight inspections were made under this schedule with seven inspections made before establishment of this schedule. Visual inspections showed that wear corrosion occurs at points where the fuel bundle end brackets, fuel bundle wire wraps, and fuel rod wire wraps contact the process tube wall. Wear corrosion was observed in all tubes. Pressure tubes in which fuel elements were removed and replaced show evidence of new wear corrosion. Upper and lower fuel element end brackets produced wear corrosion in all tubes. Spiral wire wraps of individual fuel rods produced wear corrosion mainly near the ends of some fuel bundles. Spiral wire wraps of fuel bundles produced wear corrosion randomly in the tubes. This was observed in all tubes charged with fuel elements of this type. Strap or wire bands of circumferentially banded fuel bundles produced little or no wear corrosion. Measurements showed that the tube wall penetration by wear corrosion ranges from less than one mil to about l2 mils. Evidence of severe mechanical damage from fuel bundle charge-discharge operation was not observed. Inside diameter measurements showed that there was no significant creep deformation of the process tubes. There was no detectable tube diameter increase within measuring instrument accuracy (~ plus or minus 2 mils). This behavior was consistent with data from creep tests on sections of pressure tubes and superior to performance predicted by tensile creep data from annealed Zircaloy-2 strip. For most of the channels inspected, the measured eccentricity of the helium gas annulus separating the Zircaloy-2 pressure tube and the aluminum shroud tube, was small and well within specifications. In two channels, 1348 and 1857, the eccentricity of the helium gas annulus exceeded oper ating specification. (Operating specifications limit the closest approach of the Zircaloy-2 pressure tube to the aluminum shroud tube to 50 mils.) In the case of Channel 1857, this specification was exceeded twice since PRTR startup. Over-all results from the PRTR pressure tube monitoring program indicate the tubes to be performing satisfactorily on a creep strength basis. The effects of wear corrosion are being evaluated. (auth)

• Research Organization: General Electric Co. Hanford Atomic Products Operation, Richland, Wash.
• DOE Contract Number: AT(45-1)-1350
• NSA Number: NSA-16-034112
• OSTI ID: 4798659
• Report Number(s): HW-73701(Rev.)
• Country of Publication: United States
• Language: English

Related Subjects

ALUMINUM
CORROSION
CREEP
DEFORMATION
FAILURES
FUEL ELEMENTS
HELIUM
INSPECTION
LABORATORY EQUIPMENT
MEASURED VALUES
MONITORING
OPERATION
PERFORMANCE
PRESSURE
REACTOR TECHNOLOGY
REACTORS
REMOTE HANDLING
TENSILE PROPERTIES
TESTING
THICKNESS
TUBES
WEAR
WIRES
ZIRCALOY