Carolinas–Virginia Tube Reactor
Carolinas-Virginia Tube Reactor | |
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PHWR | |
Power generation | |
Units decommissioned | 1 x 17 MWe |
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Commons | Related media on Commons |
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Carolinas–Virginia Tube Reactor (CVTR), also known as Parr Nuclear Station, was an experimental pressurized tube
Reactors using
In conceptual terms, CVTR is very similar to the
Background
Light water designs
Conventional
In the case of a nuclear plant, the boiler is replaced with the reactor, which is more complex than a coal boiler for a number of reasons. For one, the water not only acts as the cooling fluid, but also as the neutron moderator, which means its control is vital to the operation of the system as a whole. Additionally, the water tends to pick up radioactivity from the reactor's operation, which leads to safety concerns and maintenance overhead. Finally, steam and liquid water have different moderating qualities, so most (but not all) light water designs keep the water below the boiling point and use a steam generator to feed the turbines.
The major advantage to the light water design concept is that it is simple and similar to existing systems in many ways. It has one major disadvantage, however, which is that the water removes neutrons which lowers the reactor's overall neutron economy. This is enough of an effect that there are not enough neutrons of the right energy to maintain the chain reaction in natural uranium fuel. This requires such designs to use enriched uranium to offset this effect, which increases the price of fuel.
Heavy water concept
Using natural uranium in a reactor would offer the advantage of lowered fuel costs and better availability as the supply is not dependent on the enrichment cycle. This also offers some protection against nuclear proliferation. In order to do so, the reactor needs to use some other form of moderator that improves the neutron economy. Several such moderators have been suggested, including carbon dioxide as in the UK Advanced Gas-cooled Reactor, liquid metals including sodium or lead as in various breeder reactors, and heavy water.
Of these, heavy water has the major advantage that it is simple to work with. The downside is that it is expensive and a limited resource. This led to the pressurized tube reactor concept, where the pressurized section of the system contains only enough coolant to cool the reactor, the rest of the moderator is placed around it in an unpressurized vessel. In the case of a loss-of-coolant event, only the water in the pressurized system would be lost.[2]
Design
Design of the CVTR began around 1955. CVTR had a thermal output of about 65 MWth and a gross electrical output of 19 MW.
The reactor consisted of 36 vertical U-tube fuel channels in a moderator tank which was 10 feet in diameter and 16 feet tall. Each leg of the U-tube contained one fuel assembly made up of 19
During power operation, heavy water was circulated by primary pumps through the U-tubes containing the fuel assemblies which heated the water. The heated water then flowed through an inverted U-tube
The U-shaped pressure tubes containing the fuel were thermally isolated from the hot fuel assembly by two circular thermal baffle tubes around the fuel assembly. This allowed the pressure tubes to operate at low temperatures, essentially that of the moderator tank which was maintained about 155 degrees F and close to atmospheric pressure. The moderator tank contained heavy water which moderated the fission process during operation of the reactor.[2]
The CVTR
The reactor and facilities were located at
Construction
The site for the CVTR was approved by the Atomic Energy Commission’s Advisory Committee on Reactor Safeguards in January 1959.[4] Construction started on January 1, 1960.[1][2]
CVRT was the first US heavy water power reactor.[3]
Operation
CVTR was operated by the Carolinas Virginia Nuclear Power Associates, which was a consortium of the following utilities:
The reactor went critical for the first time on March 30, 1963.[3] CVTR operated successfully from 1963 to 1967. It was shut down after the completion of the planned test program.[2] Staff:
Harry Ferguson, General Manager (initial); Mayhue Bell (later) Walt Selkinghouse, Plant Superintendent Paul Barton, Operations Supervisor Shift Supervisors: James Wright; Pete Beament; Stan Nabow; J. Ed Smith Shift Nuclear Engineers: Sam McManus; Doug Simpson; Larry E. Smith; Joseph M."Mack" McGough Health Physicist: Lionel Lewis Construction Supervisor: Bill Thomas Engineering Supervisor: Shep Waggoner
Test facility use
Following decommissioning of the CVTR, the facility was used for conducting large scale tests to provide experimental information on the response of containment structures to severe events. In the late 1960s, three tests were conducted in which large volumes of steam from the nearby
Decommissioning
The CVTR has been decommissioned and its license was withdrawn. No fuel remains on site.[2] By fall of 2009, demolition was complete and the site was returned to greenfield status.
The much larger and currently operational Virgil C. Summer Nuclear Generating Station was constructed in the 1970s, and began operating in 1984, approximately three miles north of the CVTR.
References
- ^ a b c d e . IAEA. 2013-04-13 http://www.iaea.org/PRIS/CountryStatistics/ReactorDetails.aspx?current=600. Retrieved 2013-04-14.
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(help) - ^ a b c d e f g h "Archived copy" (PDF). Archived from the original (PDF) on 2007-04-13. Retrieved 2007-03-25.
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: CS1 maint: archived copy as title (link) Heavy Water Reactors: Status and Projected Development; Technical Reports Series No. 407. International Atomic Energy Agency; Vienna, 2002. - ^ a b c d [1] Crandall, J. L. et al. Lattice studies and critical experiments in D2O moderated systems. Proceedings of the Third International Conference on the Peaceful Uses of Atomic Energy. Geneva. 1964. NRC ADAMS accession number ML051680328.
- ^ a b c [2] Okrent, David. On the History of the Evolution of Light Water Reactor Safety in the United States. NRC ADAMS accession number ML090630275.
- ^ a b [3] Tills, Jack, et al. SAND2008-1224 An Assessment of MELCOR 1.8.6: Design Basis Accident Tests of the Carolinas Virginia Tube Reactor (CVTR) Containment (Including Selected Separate Effects Tests); Sandia National Laboratories, February 2008. NRC ADAMS accession number ML080840322.
External links
- Media related to Carolinas–Virginia Tube Reactor at Wikimedia Commons
- Heavy Water Reactors: Status and Projected Development, IAEA Technical Report No. 407 CVTR is described on pp. 52 – 55.
- Decommissioning Nuclear Power Plants