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Title: The Very High Temperature Reactor

Abstract

The High Temperature Reactor (HTR) and Very High Temperature Reactor (VHTR) are types of nuclear power plants that, as the names imply, operate at temperatures above those of the conventional nuclear power plants that currently generate electricity in the US and other countries. Like existing nuclear plants, heat generated from the fission of uranium or plutonium atoms is carried off by a working fluid and can be used generate electricity. The very hot working fluid also enables the VHTR to drive other industrial processes that require high temperatures not achievable by conventional nuclear plants (Figure 1). For this reason, the VHTR is being considered for non-electrical energy applications. The reactor and power conversion system are constructed using special materials that make a core meltdown virtually impossible.

Authors:
;
Publication Date:
Research Org.:
Idaho National Laboratory (INL)
Sponsoring Org.:
DOE - NE
OSTI Identifier:
1027878
Report Number(s):
INL/JOU-10-17588
TRN: US1105288
DOE Contract Number:
DE-AC07-05ID14517
Resource Type:
Journal Article
Resource Relation:
Journal Name: Nuclear Energy Encyclopedia: Science, Technology, and Applications; Journal Volume: Chapter 26
Country of Publication:
United States
Language:
English
Subject:
11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS; ATOMS; ELECTRICITY; FISSION; HOT WORKING; MELTDOWN; NUCLEAR POWER PLANTS; PLUTONIUM; URANIUM; WORKING FLUIDS; VHTR+TDO+NGNP+HTGR+LWR+HTR+Fuel

Citation Formats

Hans D. Gougar, and David A. Petti. The Very High Temperature Reactor. United States: N. p., 2011. Web.
Hans D. Gougar, & David A. Petti. The Very High Temperature Reactor. United States.
Hans D. Gougar, and David A. Petti. 2011. "The Very High Temperature Reactor". United States. doi:.
@article{osti_1027878,
title = {The Very High Temperature Reactor},
author = {Hans D. Gougar and David A. Petti},
abstractNote = {The High Temperature Reactor (HTR) and Very High Temperature Reactor (VHTR) are types of nuclear power plants that, as the names imply, operate at temperatures above those of the conventional nuclear power plants that currently generate electricity in the US and other countries. Like existing nuclear plants, heat generated from the fission of uranium or plutonium atoms is carried off by a working fluid and can be used generate electricity. The very hot working fluid also enables the VHTR to drive other industrial processes that require high temperatures not achievable by conventional nuclear plants (Figure 1). For this reason, the VHTR is being considered for non-electrical energy applications. The reactor and power conversion system are constructed using special materials that make a core meltdown virtually impossible.},
doi = {},
journal = {Nuclear Energy Encyclopedia: Science, Technology, and Applications},
number = ,
volume = Chapter 26,
place = {United States},
year = 2011,
month = 6
}
  • Reactor 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 ofmore » 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.« less
  • The influence of the main systematic factors of overheating (such as nonuniformity of power density and cold leaks of coolant) on the fuel temperatures in a very high temperature gas-cooled reactor NGNP (Next Generation Nuclear Plant) with prismatic fuel blocks is studied. The results of computations show a high sensitivity of the fuel temperatures to systematic factors of overheating. This circumstance indicates the necessity of high-precision three-dimensional modeling of the gas dynamics and heat transfer in the core when designing this type of reactor.
  • Release characteristics of volatile metallic fission products from the coated fuel particle and the reactor core for a very high temperature gas-cooled reactor during its power operation has been studied using numerical analysis. A computer code FORNAX, based on Fick's diffusion law and the evaporation mass transfer relation, has been developed, which considers, in particular, distribution and time histories of power density, fuel temperature, and failed and degraded fuel particle fractions in the core. Applicability of the code to evaluate the core design has been shown and the following have been indicated on the release of cesium from the reactor:more » 1. The release from the intact fuel particles by diffusion through their intact coatings shows larger contribution in the total core release at higher temperature. 2. The diffusion release from the intact particle is governed not only by the diffusion in the silicon carbide layer but also by that in the fuel kernel.« less
  • A sequential analysis was made on the material degradations during exposure of nickel-base corrosionresistant austenitic alloys to simulated very high temperature reactor environments. The materials tested were two modified versions of Hastelloy-X in terms of both increased manganese content for improved compatibility and decreased manganese content for possible adverse effects. Quantitative analysis of the specimens after exposure for 1000 h at several temperature steps from 850 to 1050/sup 0/C have revealed the temperature-dependent aspects of the processes including the depletion of chromium and manganese due to oxidation, evaporation, and carbon transfer into and/or from the materials. The material with enrichedmore » manganese, developed and specified as Hastelloy-XR, showed enhanced resistance to loss of chromium in terms of both oxidation and evaporation.« less