THTR commissioning and operating experience

Bäumer, R.; Kalinowski, I.

doi:10.1016/0360-5442(91)90087-3

Cited by 27 publications

(7 citation statements)

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“…THTR exhibited fair reliability for the brief operating life it had: 61% in 1987 and 52% in 1988 (Baumer and Kalinowski 1991). The limited information available indicates that both HTTR and HTR-10 have had good availability since they were put into operation.…”

Section: Resultsmentioning

confidence: 99%

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High Temperature Gas Reactors: Assessment of Applicable Codes and Standards

McDowell¹,

Nickolaus²,

Mitchell³

et al. 2011

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SummaryCurrent interest expressed by industry in HTGR plants, particularly modular plants with power up to about 600 MW(e) per unit, has prompted NRC to task PNNL with assessing the currently available literature related to codes and standards applicable to HTGR plants, the operating history of past and present HTGR plants, and with evaluating the proposed designs of RPV and associated piping for future plants.Considering these topics in the order they are arranged in the text, first the operational histories of five shut-down and two currently operating HTGR plants are reviewed, leading the authors to conclude that while small, simple prototype HTGR plants operated reliably, some of the larger plants, particularly Fort St. Vrain, had poor availability. Safety and radiological performance of these plants has been considerably better than LWR plants. Petroleum processing plants provide some applicable experience with materials similar to those proposed for HTGR piping and vessels.At least one currently operating plant -HTR-10 -has performed and documented a leak before break analysis that appears to be applicable to proposed future US HTGR designs.Current codes and standards cover some HTGR materials, but not all materials are covered to the high temperatures envisioned for HTGR use. Codes and standards, particularly ASME Codes, are under development for proposed future US HTGR designs. A -roadmap‖ document has been prepared for ASME Code development; a new subsection to section III of the ASME Code, ASME BPVC III-5, is scheduled to be published in October 2011.The question of terminology for the cross-duct structure between the RPV and power conversion vessel is discussed, considering the differences in regulatory requirements that apply depending on whether this structure is designated as a -vessel‖ or as a -pipe‖. We conclude that designing this component as a -pipe‖ is the more appropriate choice, but that the ASME BPVC allows the owner of the facility to select the preferred designation, and that either designation can be acceptable.v

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Section: Resultsmentioning

confidence: 99%

“…Initial criticality was on September 13, 1983, the generator was synchronized to the grid for the first time on November 16, 1985, and full power reached on September 23, 1986 (Baumer and Kalinowski 1991).…”

Section: Thtr Plant Descriptionmentioning

confidence: 99%

High Temperature Gas Reactors: Assessment of Applicable Codes and Standards

McDowell¹,

Nickolaus²,

Mitchell³

et al. 2011

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“…It is not entirely clear how significant generation of dust and particulates could be; however, it was shown in the THTR that only 65 kg of graphite from the reflectors was oxidized and presumably removed as particulate during the total period of plant operation of about two years. 4 The rate of dust production in AVR was estimated to be 3 kg per year. 22 This rate of production corresponds to an average density of dust in the gas of 5μg/ m 3 ; the…”

Section: Impurities In Helium-cooled High Temperature Gas-cooled Reacmentioning

confidence: 99%

Kinetics of Gas Reactions and Environmental Degradation in NGNP Helium

Wright¹

2006

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A number of very high temperature helium-cooled reactors have been built and operated for extended periods. The helium coolant in the primary circuit has been found to contain low levels of impurities after steady-state operation that can lead to an environmental degradation of the high temperature alloys used for internals and heat exchangers. Depending on the impurity concentration and the temperature, high temperature alloys can undergo oxidation, carburization, or decarburization. The concentration of H 2 O and CC are of particular interest because they essentially control the oxygen partial pressure and carbon activity, respectively. The optimum coolant chemistry for long-term stability of high temperature alloys is slightly oxidizing and results in formation of a tenacious and protective Cr 2 O 3 scale.The most critical metallic component of the Next Generation Nuclear Plant (NGNP) is the heat exchanger. Inconel 617 is the primary candidate alloy for this application because of its superior creep resistance. The mechanisms of environmental interaction between this alloy and prototype Very High Temperature Reactor (VHTR) helium chemistries have been extensively studied. A modified type of Ellingham diagram that maps the ranges of carbon activity and oxygen partial pressure that result in each of the degradation mechanisms has been developed. In addition, at temperatures above about 950°C, additional degradation mechanisms arise that effectively determine the maximum temperature for sustained service. While the mechanisms of degradation are relatively well-known, the kinetics of the reactions for reactor conditions of high helium pressure and velocity are not well characterized.

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“…Most of the researches and operating experiences of thorium utilization in HTR are focused on high enriched uranium (HEU) (Baumer and Kalinowski, 1991;Habush and Harris, 1968) or low enriched uranium (LEU) (Pohl, 2006;Ding and Kloosterman, 2014).…”

Section: Introductionmentioning

confidence: 99%