The open valve permitted coolant water to escape from the primary system, and was the principal mechanical cause of the primary coolant system depressurization and partial core disintegration that followed.
32.
The pressure in the primary coolant loop is typically, which is notably higher than in other nuclear reactors, and nearly twice that of a boiling water reactor ( BWR ).
33.
Even though the power generation used primary coolant, it is reported that the AVR exposed its personnel to less than 1 / 5 as much radiation as a typical light water reactor.
34.
Pressure transients in the primary coolant system manifest as temperature transients in the pressurizer and are controlled through the use of automatic heaters and water spray, which raise and lower pressurizer temperature, respectively.
35.
Two things are characteristic for the pressurized water reactor ( PWR ) when compared with other reactor types : coolant loop separation from the steam system and pressure inside the primary coolant loop.
36.
Fast breeder reactors ( FBR ) produce about an order of magnitude less C-14 than the most common reactor type, the Pressurized water reactor, as FBRs do not use water as a primary coolant.
37.
The primary coolant enters the pressure vessel through two 16-in . ( 40.64-cm )-diameter pipes above the core, passes through the core, and exits through an 18-in . ( 45.72-cm )-diameter pipe beneath the core.
38.
Reactor primary coolant pumps are one of the primary sources of noise from submarines, and the elimination of coolant pumps and associated equipment would also reduce mechanical complexity and the space required by propulsion equipment.
39.
These loops also have an important safety role because they constitute one of the primary barriers between the radioactive and non-radioactive sides of the plant as the primary coolant becomes radioactive from its exposure to the core.
40.
However, although it was originally planned that Skylab crews would only perform limited maintenance they successfully made major repairs during EVA, such as the SL-2 crew's deployment of the solar panel and the SL-4 crew's repair of the primary coolant loop.
