Instrument evaluation, calibration, and installation for the heater experiments at Stripa
Borehole instrumentation for the measurement of temperature, displacement, and stress was evaluated, modified, calibrated, and installed in an underground site at Stripa, Sweden where experiments are currently underway to investigate the suitability of granite as a storage medium for nuclear waste. Three arrays of borehole instrumentation measure the thermomechanical effects caused by electrical heaters which simulate the thermal output of canisters of radioactive waste. Because most rock mechanics investigations are carried out at modest temperatures, a sustained operating temperature as high as 200/sup 0/C was an unusual and most important criterion governing the instrumentation program. Extensive laboratory experiments were conducted to determine the effect of high temperature on instrument behavior and also to develop calibration and data-reduction procedures. The rod extensometers were tested for anchor creep, the selection of a suitable high-temperature pressurizing fluid, and the thermal stability of the grout. Four temperature corrections are incorporated into the data reduction of the USBM borehole deformation measurement: the bridge voltage offset correction, the change in calibration factor induced by temperature, and the thermal expansion of the gage and of the rock. The vibrating wire gages were calibrated in the laboratory by loading gages installed in a granite block at pressures up to 13 MPa and at temperatures ranging from 20/sup 0/ to 200/sup 0/C. Both the slope and offset of the response equation are corrected for temperature effects. Most thermocouples were calibrated in an oven at the field site. Thermocouples were emplaced with individual gages and into holes backfilled with sand or grout.
- Research Organization:
- California Univ., Berkeley (USA). Lawrence Berkeley Lab.; Terra Tek, Inc., Salt Lake City, UT (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 5267336
- Report Number(s):
- LBL-8313; SAC-25
- Country of Publication:
- United States
- Language:
- English
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12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
58 GEOSCIENCES
580300 -- Mineralogy
Petrology
& Rock Mechanics-- (-1989)
BOREHOLES
CAVITIES
DATA
DISPLACEMENT RATES
EUROPE
EXPANSION
EXPERIMENTAL DATA
EXTENSOMETERS
FIELD TESTS
GRANITES
HIGH TEMPERATURE
HIGH-LEVEL RADIOACTIVE WASTES
IGNEOUS ROCKS
INFORMATION
MANAGEMENT
MEASURING INSTRUMENTS
MECHANICAL EFFECTS
MECHANICAL PROPERTIES
NUMERICAL DATA
PLUTONIC ROCKS
RADIOACTIVE MATERIALS
RADIOACTIVE WASTE DISPOSAL
RADIOACTIVE WASTES
ROCK MECHANICS
ROCKS
SCANDINAVIA
SIMULATION
STRESSES
SWEDEN
TEMPERATURE EFFECTS
TEMPERATURE MEASUREMENT
TESTING
THERMAL EXPANSION
THERMOCOUPLES
UNDERGROUND DISPOSAL
WASTE DISPOSAL
WASTE MANAGEMENT
WASTES
WESTERN EUROPE