Submarine pressurized water reactors

Six of the seven nuclear submarines contained two pressurized water reactors (PWRs) each. Eleven of these PWRs were dumped into the Kara Sea between 1965 and 1988 eight within and three without their reactor compartments (RCs). AH these nuclear submarines suffered some form of reactor accident however, many specifics of the reactor design, maximum thermal power, compartment layout, detailed operating histories, and accident scenarios remain classified. 

Disposal site Year of disposal Factory Dumped unit Disposal coordinates Disposal depth (m) Number of reactors Total activity (PBq)  

Tsivolka Fjord 1967 OK-150 Reactor compartment and special container with fuel 74 26.10 N 58 36.15 E 50 3 0.6 20 2.2 

Approximate locations of the marine reactor disposal sites in the Kara Sea on the northeast coast of Russia. 

A criticality accident aboard the submarine identified as factory number 421 is known to have caused over pressurization of the right board reactor pressure vessel (RPV). The fuel rods were reported to not be damaged however, a decision was made to not re-use the RPV. As such, the SNF was not removed. 

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Another reactor that was approved for development was a land-based prototype submarine propulsion reactor. Westinghouse Electric Corp. designed this pressurized water reactor, using data collected by Argonne. Built at NRTS, the reactor used enriched uranium, the metal fuel in the form of plates. A similar reactor was installed in the submarine l autilus. 

The first three submarine reactors disposed of in this way seems have originated from a Hotel, a November and a Yankee class submarine, all of early designs, and they had all suffered either a criticality or a loss-of-cooling accident. They were all provided with two pressurized water reactors. The submarine was the Project 645 submarine with a November class hull, which was provided with two liquid-metal cooled reactors. It had suffered a loss-of-cooling accident in one of its reactors [4]. 

The pressurized water reactor is generally preferred for propulsion purposes (military surface vessels and submarines), partly because it can react faster on changes in power demand than many other types of thermal reactors. 

In the beginning of the 1950s nearly at the same time the USA and USSR launched the development of the nuclear power installations (NPI) for nuclear submarines (NS). In both countries the work was carried out for two types of NPIs with pressurized water reactors and reactors cooled by liquid metal coolant (LMC). 

Nuclear powered submarines, iike the USS Maryiand shown here, typicaiiy use pressurized water reactors and highiy enriched nuciear fuei to provide more power from a smaiier reactor. One steaith issue with nuciear subs is the need to cooi the reactor, which ieaves a traii of warm water that rises to the surface. 

But when the United States discovered in September that the Soviet Union had detonated its first atomic device the previous month, a renewed emphasis on military weapons and military reactor applications kept the development of civilian power reactors consigned to a low priority. The subsequent atomic-arms race also helped establish a preference among various reactor designs by giving an edge to Rickover s pressurized-light-water reactor for submarine propulsion. ... 

Uranium Enrichment. Enrichment of uranium-235, from 0.711 percent as present in natural uranium, is essential to the economical operation of the light water reactors. The fuel life for these reactors is a function of the enrichment. With 3.4 percent U-235 fuel, the pressurized light water reactors produce 33,000 megawatt-days of energy/ metric ton during the three years the fuel is in the reactors. In the naval submarine and ship reactors using highly enriched U-235, the fuel life exceeds ten years. 

Meanwhile, GE built the prototype for their sodium cooled reactor at the Kessehing site. West Milton, NY, a location near its Knolls Atomic Power Laboratory (R. G. Hewlett and Duncan, 1974). The SIR, the land-based prototype for GE s sodium cooled reactor for submarine propulsion, reached initial criticality in 1955. The intended value of the sodium reactor was its ability to function at a higher operating temperature. It would thereby generate steam at a higher temperature and produce higher overall plant efficiency. Sodium also provided improved heat transfer compared to water, and would allow lower pressure and thinner walled pressure vessels. The SIR reactor worked to demonstrate these advantages, but was shut down in 1957 (TID 8200, n.d.). 

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