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Title: Direct disposal of spent fuel in rock salt: Geomechanical effects and gas release

At the Asse salt mine in Germany a test field has been operating since September 1990 for the purpose of demonstrating the practicability of the direct disposal of spent fuel elements in drifts. According to the concept for direct disposal of spent fuel, disposal casks called Pollux will be emplaced on the floor of the drifts backfilled with salt afterwards. The main objectives of this test are studies on the thermal and thermomechanical effects in the backfilled drifts and in the surrounding rock due to the power output of the spent fuel in the casks. The temperatures at the surface of the electrically heated mock-ups of the Pollux-casks increased up to 210 C after five months and then gradually decrease. Determinations of the initial stress state in the test field were carried out by overcoming and slot cutting techniques before the test drifts were opened. After the beginning of heating the casks, the rock stresses increased rapidly related to the temperature at the specific location and later on decreased slowly. Deformation measurements are performed in the host rock using multi-point extensometers and closure gauges for measuring the closure of the test drifts in the heated as well as in themore » unheated areas. Specially designed equipment was used to observe the settling of the backfill. In the period of about 4 years, the convergence of the backfilled drifts accelerated enormously and caused backfill pressures up to 1.8 MPa. The concentrations of the main components carbon dioxide, hydrogen, and methane in the pore volume of the backfill were analyzed.« less
Authors:
; ;  [1] ;  [2]
  1. Forschungszentrum fuer Umwelt und Gesundheit GmbH, Braunschweig (Germany). Inst. fuer Tieflagerung
  2. Bundesanstalt fuer Geowissenschaften und Rohstoffe, Hannover (Germany)
Publication Date:
OSTI Identifier:
182957
Report Number(s):
CONF-950917-
ISBN 0-7918-1219-7; TRN: IM9608%%326
Resource Type:
Book
Resource Relation:
Conference: 5. international conference on radioactive waste management and environmental remediation, Berlin (Germany), 3-9 Sep 1995; Other Information: PBD: 1995; Related Information: Is Part Of Fifth international conference on radioactive waste management and environmental remediation -- ICEM `95: Proceedings. Volume 1: Cross-cutting issues and management of high-level waste and spent fuel; Slate, S.; Feizollahi, F.; Creer, J. [eds.]; PB: 900 p.
Publisher:
American Society of Mechanical Engineers, New York, NY (United States)
Country of Publication:
United States
Language:
English
Subject:
05 NUCLEAR FUELS; SALT DEPOSITS; RADIOACTIVE WASTE DISPOSAL; FEDERAL REPUBLIC OF GERMANY; RADIOACTIVE WASTE FACILITIES; SPENT FUELS; UNDERGROUND DISPOSAL; PERFORMANCE TESTING; THERMAL ANALYSIS; STRESS ANALYSIS; EXPERIMENTAL DATA; SPENT FUEL CASKS; BACKFILLING; ROCK MECHANICS; RESERVOIR PRESSURE; RADIOLYSIS; TEST FACILITIES; RESERVOIR TEMPERATURE; STRATA MOVEMENT; BULK DENSITY