3.12 Welding of Nuclear Components. .. . 3.13 Nuclear Reactor Facility Materials 3.14 Decomissioning of•Reactor Facilities. 4. REACTOR A program will be developed to periodically update ~nd revise the Design Guide as necessary to reflect future standards, revisions and developments and to incorporate changes recommended by the Design Guide users. In this manner,.
NU'l'lL:E This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the Unite9 States Government nor any agency thereof, or any uf their employees, makes any warranty, expressed or implied, or assumes any kgalliability or responsibility for any third party's use, or the results of such use, or any information, apparatus, product or process disclosed in this report, or represents that its use by such third party would not infringe privately owned rights. The Department of Energy (DOE) is the successor to the Energy Research and Development Atllllinistration (ERDA) and all references to ERDA herein shall be deemed to refer to DOE.
A program will be established for the periodic rev1s1on •of •the Design Guides and for the provision of additional information, as necessary, during the period between rev1s1ons. Chapter 18 includes preaddressed comment sheets to facilitate feedback from the Design Guide users. Comments .will be reviewed and changes will be made to the g~ide, as necessary, at its next scheduled revision.
After nearly thirty years of operation, Brookhaven's High Flux Beam Reactor (HFBR) is still one of the world's premier steady-state neutron sources. A major center for condensed matter studies, it currently supports fifteen separate beamlines conducting research in fields as diverse as crystallography, solid-state, nuclear and surface physics, polymer physics and structural biology and will very likely be able to do so for perhaps another decade. But beyond that point the HFBR will be running on borrowed time. Unless appropriate remedial action is taken, progressive radiation-induced embrittlement problems will eventually shut it down. Recognizing the HFBR's value as a national scientific resource, members of the Laboratory's scientific and reactor operations staffs began earlier this year to consider what could be done both to extend its useful life and to assure that it continues to provide state-of-the-art research facilities for the scientific community. summarizes the findings of that study. It addresses two This report basic issues : (i) identification and-replacement of lifetime-limiting components and (ii) modifications and additions that could expand and enhance the reactor's research capabilities. I1 Identification and Replacement of Life-Limiting Components of the HFBR Generally speaking, replacement of HFBR components in regions where the radiation fields are high is a relatively straightforward operation. There are two important exceptions: replacing either the reactor vessel or thermal shield is, undeniably, a major undertaking. Thus the structural integrity of these two components ultimately determines the operating life of the reactor. Considering first the (6061 aluminum alloy) reactor vessel, we see in Fig. 1 (a) that the thimbles (of the same 6061 alloy) that define the external beams are welded to its walls and extend inward to the region of peak flux. their inner ends, the rate of neutron-induced-aluminum-tosilicon transmutation is sufficient to harden the alloy and gradually reduce its ductility. Any leakage of heavy water coolant through a crack in a radiation-embrittled thimble At tip would require immediate shutdown of the HFBR.
In addition to the guidelines applicable to specific systems, guidelines are provided for reactor facility siting, general component and system design, conduct of operations, initial test programs, accident analysis, technical specifications and quality assurance. For each reactor system, and for each of the general topical areas described above, the Design Guide recommends industry and NRC standards, codes and guides and the applicable portions of 10 CFR (including the General Design Criteria in 10 CFR 50, Appendix A) to be considered by the DOE reactor facility contractor. Many existing nuclear industry standards and codes and ysNRC Regulatory Guides, although written primarily for commerical power reactors, are also generally applicable to the design 6f certain Category II reactors. The Design Guide includes design guidelines which provide interpretations of the standards, codes, and guides in order to facilitate their application to Category II reactors. When criteria from existing standards, codes, and guides do not provide adequate guidance, the design guidelines include interim recommendations for the designer pending the development or approval of appropriate new standards, codes, and guides. Aided by the introductory guidance provided by the Design Guide, it remains for the designer to consult the appropriate referenced standards, codes, and guides in order to be f~lly appraised of all system design requirements. All of the applicable standards, codes, and guides that are recommended for consideration by the designer are available from the appropriate issuing organization. A program will be developed to periodically update and revise the Design Guide as necessary to reflect future standards, revisions and developments and to incorporate changes recommended by the Design Guide users. In this manner, the Design Guide will remain a timely standard reference for the designer and reviewer, alike.
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