[en] This report discusses the decommissioned Piqua Nuclear Power Facility which is located in Piqua, Ohio near the Greater Miami River. The Facility was built by the US Atomic Energy Commission (now U. S. Department of Energy) and was operated from 1963 to 1966. The reactor was retired prior to 1970 and the facility was leased to the city of Piqua for use as offices and equipment storage. In December 1991, a radiological survey was done of the facility to document its radiological condition. The data show that all radiological parameters measured were essentially the same as that found in the natural environment. The only exception was that low levels of radioactive contamination were detected in one drain on the 56.5 ft elevation, but the radiation exposure rate in that area was also typical of natural background

[en] The Organic Moderated Reactor Experiment (OMRE) facility was designed to investigate and develop organic coolant technology and was operated at the Idaho National Engineering Laboratory (INEL) from 1957 until 1963. Following final reactor shutdown, the nuclear fuel and reactor vessel internals were removed and the organic coolant (Sanowax) was drained from all systems. The facility remained in this deactivated condition until October, 1977. At that time dismantling and removal of the facility was started. The OMRE Decontamination and Decommissioning (D and D) project involves the removal of all reactor systems, the reactor vessel, buildings, roadways, parking lots, power lines, contaminated soil, and fences. The area will then be returned to its natural state by grading and seeding with crested wheat grass. Details pertaining to management of the project, technical approaches, costs, schedules, radiation levels, waste volumes, and final disposition are presented. Photographs showing various stages of the dismantling operations are also included

[en] This paper describes the removal of a radiologically contaminated concrete pad. This pad was removed during 1979 by operating personnel under the direction of the Waste Management Program of EG and G Idaho, Inc. The concrete pad was the foundation for the Organic Moderated Reactor Experiment (OMRE) reactor vessel located at the Idaho National Engineering Laboratory (INEL). The pad consisted of a cylindrical concrete slab 15 ft in diameter, 2 ft thick, and reinforced with steel bar. It was poured directly onto basalt rocks approximately 20 ft below grade. The entire pad contained induced radioactivity and was therefore demolished, boxed, and buried rather than being decontaminated. The pad was demolished by explosive blasting

[en] The Hallam Nuclear Power Facility, a sodium cooled, graphite moderated, 256 Mw(t) power reactor, went critical in 1962, was shut down as a result of moderator problems in 1964, and was decommissioned in 1969. The Piqua Nuclear Power Facility, an organic cooled, 45 Mw(t) power reactor went critical in 1963, was shut down in 1966 because of coolant problems, and was decommissioned in 1969. Fuel, coolant, and support systems of both reactors were removed from the site. The reactor vessels are entombed at their sites. Remaining systems at Hallam were sealed in the underground vaults and were then covered with six feet of earth. The Piqua vessel is sealed in the concrete reactor containment building. The state of Nebraska is responsible for monitoring 3 x 10⁵ curies in 1969. The Piqua site was purchased by the U. S. Government and then leased to the City of Piqua. The remaining radioactivity at Piqua was 2.6 x 10⁵ curies

[en] Radiolytic damage to the ditolylmethane organic coolant-moderator of the ARBUS reactor was removed by vacuum distillation. The majority of the degraded ditolylmethane formed gaseous and high-boiling materials, which were easily removed by the vacuum distillation. Unsaturated hydrocarbons and low-boiling residues were a minor contribution to the impurities produced by radiolysis in the primary coolant loop. Radioactivity in the primary coolant loop was found to be caused primarily from corrosion products of the system, ¹⁶N from dissolved oxygen, and impurities in the coolant-moderator. These also were significantly reduced in the vacuum distillation process

[en] Experimental results obtained with test operation of the experimental nuclear power plant ARBUS with ditolilmethane as the coolant and moderator are presented. The problems to have been studied were as follows: ditolilmethane radiolysis under operating conditions: efficiency of ditolilmethane distillation purification from radiolysis products; ditolilmethane activation in the reactor and radiation conditions in the station building rooms. (author)

[en] The flowsheet and main characteristics of the AST-1 (ARBUS) reactor organic cooled testing loop are considered. The conclusion is made that the described loop operation is simple and reliable and provides the condition maximally close to the real ones when testing the experimental fuel elements for the nuclear power plants for district heating

[en] This report describes the decontamination and decommissioning (D and D) of the Organic Moderated Reactor Experiment (OMRE) facility performed from October 1977 through September 1979. This D and D project included removal of all the facilities and as much contaminated soil and rock as practical. Removal of the reactor pressure vessel was an unusually difficult problem, and an extraordinary, unexpected amount of activated rock and soil was removed. After removal of all significantly contaminated material, the site consisted of a 20-ft deep excavation surrounded by backfill material. Before this excavation was backfilled, it and the backfill material were radiologically surveyed and detailed records made of these surveys. After the excavation was backfilled and graded, the site surface was surveyed again and found to be essentially uncontaminated

No abstract available

[en] Thermal properties and thermal stability of widely spread organic and organosilicon coolants (polyphenils, alkyldiphenyls, polyorganosiloxans) are considered. Experimental data are systematized and generalized, recommended methods for experimental study are described. Tables of thermal properties under atmospheric pressure in the temperature range from melting points up to 400 deg C are presented