摘要:

AbstractThe pebble-bed prototype thorium high-temperature reactor represents the second step of high-temperature gas-cooled reactor development in the Federal Republic of Germany. Nuclear commissioning of the plant began in August 1983 with the loading of the spherical elements, and first criti-cality was achieved in September 1983 with the loading of 198 180 spherical elements. A very good agreement of 0.004Δk was achieved between measured and calculated values. After full loading of the core with 674200 elements in October 1983, core physics tests were performed in air and nitrogen in August 1984 to verify the design calculations. In these tests the temperature coefficient, the control rod worths, and the reactivity of the reactor core were measured. The measured values of the temperature coefficient were within 10% of the expected values. The agreement between measured and expected control rod worths (5%) is excellent. The reactivity of the cold core with all rods withdrawn was determined to be 0.112±0.005Δp. Taking into account values of the packing density of the spherical elements, which were higher than expected, the calculated value of 0.11Δp was in very good agreement.

ISSN:0029-5639    

DOI:10.13182/NSE87-A27457

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractDuring the startup phase of the thorium high-temperature reactor (THTR)-300, control rod reactivity measurements are performed to meet the demands of the licensing authorities as well as to adjust the operating instrumentation. From several possibilities the inverse kinetic method has been chosen because of its easy implementation, high stability against disturbing signals, and great accuracy. An outline of the basic assumptions of various methods together with tests on the Kritische Anlage Hochtemperaturreaktor are discussed, the technical equipment for the THTR is described, and results of measurements for various rod configurations are given. Finally, the transition from the special startup equipment to the standard operating instrumentation is demonstrated.

ISSN:0029-5639    

DOI:10.13182/NSE87-A27458

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractFort St. Vrain (FSV) is the only graphite-moderated, helium-cooled nuclear power plant in the United States. It was preceded by the 40-MW(electric) Peach Bottom high-temperature gas-cooled reactor (HTGR), which was permanently shut down in 1975. The Public Service Company of Colorado owns and operates FSV, and the core design and manufacture were performed by General Atomic Company (now GA Technologies, Inc.). Extensive physics testing of the 330-MW(electric) FSV HTGR was conducted to confirm the adequacy of the calculational models used in the core design. The physics testing performed during the first three cycles has confirmed that the calculational models used for the core design have been eminently successful in predicting the core nuclear performance from initial cold criticality through power operation and refueling.

ISSN:0029-5639    

DOI:10.13182/NSE87-A27459

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractThe analysis of an Oak Ridge National Laboratory Tower Shielding Facility (TSF) experiment in which measurements were made of neutrons streaming through a mockup of a section of the lower core support structure of a large-scale high-temperature gas-cooled reactor (HTGR) design concept is described. The analysis was performed with the same calculational methods used for an analysis of the HTGR design itself, the purpose of the experiment being to provide data against which the validity of the calculational methods could be tested. Also summarized are the HTGR design calculation results; how they affected the design and objectives of the TSF experiment is described. Comparisons of the neutron detector responses observed in the experiment with calculated responses showed satisfactory agreement in most cases, and the implications of these results for the HTGR shield design are highlighted. Among other conclusions, it was determined that1.the calculational methods are adequate2.neutron streaming through the HTGR core support structure is predicted reasonably well3.thermal neutron fluence levels at the HTGR lower plenum side wall are probably overestimated by at most a factor of 2.3.

ISSN:0029-5639    

DOI:10.13182/NSE87-A27460

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractReactor physics research activities in Japan that are related to the very high temperature reactor (VHTR) for multipurpose use are briefly summarized. Emphasis is placed on critical experiments. Neutronic core design accuracy required for the experimental VHTR is made clear, and nuclear data compilation and neutronic calculation code development are described. For experimental work, after a review of the results of all reactor physics experiments performed on the Semi-Homogeneous Experiment at the Japan Atomic Energy Research Institute, its reconstruction program to the VHTR critical assembly is presented. The aim of this program is to perform a detailed mockup experiment of the experimental VHTR loaded with low-enriched uranium-coated particle fuels. Finally, improvement of the neutronic calculation accuracy attained through comparison between calculation and experiment is illustrated, and some future problems are pointed out.

ISSN:0029-5639    

DOI:10.13182/NSE87-A27461

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

AbstractFor calculations of high-temperature gas-cooled reactors with low-enrichment fuel, it is important to know the plutonium cross sections accurately. Therefore, a calculational method was developed, by which the plutonium cross-section data of the ENDF/B-IV library can be examined. This method uses zero- and one-dimensional neutron transport calculations to collapse the basic data into one-group cross sections, which then can be compared with experimental values obtained from integral tests.For comparison the data from the critical experiment CESAR-II of the Centre d’Etudes Nucléaires, Cadarache, France, were utilized. In this experiment samples with different plutonium concentrations and different mixtures of the plutonium isotopes were oscillated inside the core at different temperatures between 20 and 360°C. The simulation of this experiment through the calculational model developed in the present study showed that the ENDF/B-IV data for plutonium are reasonable.

ISSN:0029-5639    

DOI:10.13182/NSE87-A27462

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor