Pressure tube reactors

The tube reactors can be refuelled during their operation, which is impossible in both PWRs and BWRs of the vessel t5q)e. To this end, a special refuelling machine is used which connects in a leak-proof way under pressure with any single tube for the time needed for the replacement of fuel. (This feature makes these reactors suitable for plutonium production, as it is possible to optimally choose the permanence of the fuel inside the reactor.) 

In Canada, where parks of CANDU tube reactors have been built (up to eight 600 MWe reactors on the same site), vacuum building containment has also been used which consists in building, for each park of reactors, a central empty containment, connected with the containments of any single reactor by a duct provided with a rupture disc or similar device. In the event of a LOCA accident in one of the reactors, the corresponding rupture disc opens and the air-steam mixture under pressure has the whole volume of the vacuum building in which to expand. In this way, the containment of each reactor can be rather small with overall economic advantages. 

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WSC-2 correlation covers the pressure range from 3.4 to 15.9 MPa (500 to 2,300 psia) and is considered to be applicable to pressure tube reactors (PTRs), pressurized water reactors (PWRs), and boiling water reactors (BWRs). It was developed exclusively from subchannel data. All 54 different clusters were analyzed using HAMBO and the correlation optimized for the calculated subchannel conditions. The basic equation for the correlation is... 

Currin, H. B., C. M. Hunin, L. Rivlin, and L. S. Tong, 1961, HYDNA—Digital Computer Program for Hydrodynamic Transients in a Pressure Tube Reactor or a Closed Channel Core, USAEC Rep. CYNA-77, Washington, DC. (6)... 

Braun, I., Schulz-Ekloff, G., Wohrle, D. and Lautenschlager, W., Synthesis of A1P04- 5 in a microwave-heated, continuous-flow, high-pressure tube reactor, Microporous Mesoporous Mat., 1998, 23, 79. 

Figure 3.22 Microwave-heated, continuous-flow, high-pressure tube reactor comprising reaction mixture inlet (1), pressure jacket (2), isolation jacket (3), reactor tube coil in the microwave-heated cavity (4), thermocouple (5), cooling jacket (6), and reaction mixture outlet (7). Reproduced with permission from [84], Copyright (1998) Elsevier...

I. Braun, G. Schulz-Ekloff, D. Wohrle, and W. Lautenschlager, Synthesis of AlP04-5 in a Microwave-heated, Continuous-flow, High-pressure Tube Reactor. Microporous Mesoporous Mater., 1998, 23, 79-81. 

In the industrial process employed by Bayer AG, Germany, m-cresol and propylene, both in the liquid state, are pumped through a pressure tube reactor, filled with activated alumina. The process is performed at a molar ratio of m-cresol propylene of 1.07 at 350-360°C, 5kg/cm and LHSV of 0.25 hr. The reaction product consists of 25% m-cresol, 60% th3nnol and 15% other products. Thymol of 99% + purity is obtained by rectification of the crude product [1]. 

Reactor. Experimental heavy water moderated, carbon dioxide cooled pressure tube reactor. 

The Group were interested in visiting SGHWR because it is a direct cycle pressure tube reactor, with some superficially similar features to the Chernobyl reactor. The moderator is, however, heavy water rather than graphite as at Chernobyl. Control is by pumping boric acid solution into liquid shutdown tubes and dumping heavy water moderator. 

Physical separation and layout of plant components REFERENCES ANNEX SAFETY FUNCTIONS FOR BWRs, PWRs AND PRESSURE TUBE REACTORS GLOSSARY... 

Type Boiling water/pressure tube reactor... 

Safety is assured in CANDU 6 through a defence in depth approach that builds on diversity and redundancy, and which takes advantage of the unique CANDU pressure tube reactor concept. Passive systems are used whenever they are shown to be reliable and economic these systems are complimented by engineered systems. The consistent application of human factors principles, and detailed attention to all aspects of plant design also contributed to CANDU 6 safety. 

Pressure Tube Reactor Critical Experiment, R. R. Powell and P. M. Williams fAMF). 

The Gentilly-1 pressure tube reactor was a 250-MWe HWM and boiling light water-cooled design fueled with natural uranium dioxide. The reactor concept had been developed in the early 1960s, and in 1966 the reactor was committed for construction. First, power was produced in 1971 and full power attained in May 1972. It was shut down in April 1979, and by 1984 had been decommissioned. 

Four gas-cooled pressure tube reactors of relatively small size were built in the 1960s with the object of exploring fhe use of CO2 as a heaf fransport fluid in combination with heavy water moderation instead of graphite. The reactors had innovative fuel designs and most had the pressure tubes vertically oriented, although the most successful unit, the EL4 plant in France had the pressure tubes horizontal. 

Another major reason why pressure-tube reactors are suitable for SCW coolant is their ability to adapt the pressure boundary to accommodate much higher pressures. At the... 

Duffey, R.B. and I. Pioro. 2006. Advanced high temperature concepts for pressure-tube reactors, including co-generation and sustainability. In Proceedings of the HTR2006 Conference, Johannesburg, South Africa. 

As a member of the CANDU family, the CANDU 300 design closely follows that of the larger CANDU 600 and CANDU 950 nuclear power plants and is is illustrated in Figure A key CANDU features include a pressure tube reactor, heavy water (D2O) moderator, natural uranium fuel, and on-power refuelling. 

Kotthoff, K. Graphite-moderated, light-water-cooled, pressure-tube reactors, in Ullmann s Encyclopedia of Industrial Chemistry, Volume A17 Nuclear Technology, p. 682-694 (1991)... 

Light water cooled heavy water moderated pressure tube reactor AHWR (BARC, India) ... 

In cases where there is a separate oxygen containing fluid moderator system (such as in a pressure tube reactor), the isotope that is the major source of radiation during reactor operation will be N. After shutdown, the radiation levels around the primary coolant system will be due mainly to activated corrosion products. The tritium present in the water coolant or moderator contributes to the radiation hazard only if it is released from the system and becomes airborne. This hazard has to be taken into account in the design of LWRs also since operation with a limited leakage of primary coolant is tolerated. 

AGRs and the calandria vault gas of pressure tube reactors, the radioactive material is mostly Ar. In the case of LWRs, fission product gases usually dominate. In pressure tube reactors, the same is true for process vents that are in direct contact with coolant (in storage tanks, etc.). 

III-43. Reactors using heavy water (deuterium oxide) as a moderator, a coolant or both have the potential for the same type of accidental release of radioactive material as the corresponding LWRs described above. For a pressure tube reactor, the analyses for loss of coolant accidents need to include ruptures of the pressure tubes as well as header or pipe breaks. Note that... 

A number of the features of pressure tube reactors that had been established by the study of the GCHWR and SCHWR, nevertheless, looked attractive - namely ... 

This outline of the conceptual thinking explains why the title SGHWR was chosen. It could equally well have been called the pressure tube boiling water reactor since the heavy water fulfills no other role than providing the neutron moderation. The Canadians have arrived at a very similar system, which has evolved from their CANDU design of pressure tube reactor, (which used pressurized heavy water as coolant and an indirect cycle) and they have called It... 

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