Gases power conversion system

In South Africa, the large national utility, Eskom, which has an installed generation capacity of about 38,000 MWe, is in the process of performing a technical and economic evaluation of a helium-cooled pebble bed module reactor. It would be directly coupled to a gas turbine power conversion system for consideration in increasing the capacity of the utility s electrical system. 

A gas-cooled nuclear reactor was chosen due to its simplicity and suitability for the space environment. There are numerous alternatives for cooling a reactor core, but gas cooling is one of the simpler methods and most attractive when used with a closed Brayton cycle (CBC) power conversion system. The use of other reactor coolants would necessitate the inclusion of a heat exchanger and introduce complicated freeze/thaw problems, increasing the complexity and the weight of the reactor. 

Etzel, K., G. Baccaglini, A. Schwartz, S. Hillman, and D. Mathis, GT-MHR Power Conversion System Design Status and Technical Issues, GA-A21827, December 1994, Presented at the IAEA Technical Committee Meeting on Development Status of Modular High Temperature Reactors and Their Future Role, November 28-30, 1994, ECN, Petten, The Netherlands. 

C.F. McDonald, F.A. Silady, R.M. Wright, K.F. Kretzinger and R.C. Haubert,"GT-MHR Helium Gas Turbine Power Conversion System Design and Development", GA-A21617, GA Project 9819, March 1994. 

The power conversion system to produce electricity from the AHTR uses a multistage molten coolant gas cycle (MCGC)/ which is based on the GT-MHR power conversion unit (PCU). With similar power output, the MCGC system is expected to be more compact and, thus, provide the potential for major reductions in the turbine building volume and power conversion system capital cost for the AHTR relative to conventional systems that use a steam Rankine cycle. 

Power conversion system cost. The costs of the power conversion system were estimated from Ref. 49. Costs are reported only at the two-digit code of account level. In addition, the turbine plant equipment, account 23, was combined with the reactor plant equipment, account 22, as GA contended that all this equipment was part of the reactor system. In order to estimate the portion of these combined costs that applied to power conversion, cost partition factors were estimated by utilizing an earlier direct cycle MHTGR document. ... 

Additional cost information. There is a more recent (2002) cost of the GT-MHR, presented as a near-term deployment option (GA-A23952). Very few cost values are presented, only total direct, total indirect, and a combined contingency plus owner s cost. An overnight value of 974 /kWh(e) is shown, which is substantially lower than the 1994 GT-MHR overnight cost of 1326 /kWh(e) used as the basis for this AHTR capital cost estimate. As the AHTR power conversion system is currently 40% of the total cost, the implied cost reduction from the more recent GT-MHR study would result in a further reduction of the estimated AHTR cost relative to that presented in Table 8.3. 

In the NPPS based on the NPP technology, the reactor is successfully combined with a dynamic power conversion system operating in a closed gas turbine Brayton cycle (helium and xenon) or in a potassium steam turbine Ranldne cycle. 

The combination of the passively safe MHR and the gas turbine power conversion system represents the ultimate in simplicity and safety. The reactor coolant directly drives the turbine which turns the generator. This allows costly and failure prone steam generating equipment to be eliminated. Advantages include ... 

XXn-10] MOISSEYTSEV, A., SIENICKI, J.J., WADE, DC., Cycle analysis of supercritical carbon dioxide gas turbine Brayton cycle power conversion system for liquid metal-cooled fast reactors, ICONE-11 (11 Int. Conf. on Nuclear Engineering, Tokyo, April 20-23, 2003), Paper ICONE 11-36023. 

Seismic design of the MARS will be performed in compliance with the procedures prescribed by the regulations. It could be noted, however, that the use of a gas-turbine unit facilitates the assurance of plant seismic resistance, as the specific mass of gas-turbine power conversion systems is -3-4.5 kg/kW and the specific volume is -0.04-0.17 mVkW, which is 10 times smaller than for the most updated steam turbine plants. 

Suggests favorable capital cost for power conversion system versus natural-gas combined cycle plants... 

The majority of inputs in this table are for the gas cooled SMRs (HTGRs) targeting the use of direct gas turbine cycles. The R D programmes address the development of turbo-machinery design, the validation and testing of power conversion system components, and further development and integrated tests of the complete power conversion systems. 

Gas turbine power conversion system feasibility issues... 

R D areas include Reactor physics fuel cycles HTR fuel technology development materials development gas turbine power conversion system feasibility issues and HTR plant safety HTR Technology Network. Partly funded by Emopean Commission Emopean multi-phase programme for HTR technology base. All phases are ciurently in work... 

The latest evolution made for the purpose of economics has been replacement of the Rankine steam cycle power conversion system with a high efficiency Brayton (gas turbine) cycle power conversion system to boost the thermal conversion efficiency to -48%. The coupling of the MHR with the gas turbine cycle forms the GT-MHR. The GT-MHR retains all of the MHR passive safety characteristics but is projected to have more attractive economics than any other generation alternative. 

The GT-MHR (Fig. XV-1) couples a gas-cooled modular helium reactor (MHR), contained in one pressure vessel, with a high efficiency Brayton cycle gas turbine (GT) power conversion system (PCS) contained in an adjacent pressure vessel. 

The GT-MHR direct Brayton cycle (gas turbine) power conversion system contains a gas turbine, an electric generator, and gas compressors located on a common, 29 m long vertically orientated shaft supported by magnetic bearings. The power conversion system also includes recuperator, pre-cooler and intercooler heat exchangers. Heated helium flows directly from the MHR into a gas turbine to drive the generator and gas compressors. Fig. XV-2. From... 

XVI-10] TAKIZUKA, T., et al., R D on power conversion system for gas turbine high temperature reactors. Nuclear Engineering and Design, (submitted). 

XVII-5] BREY, H E., Development history of the gas turbine modular high temperature reactor. Gas Turbine Power Conversion Systems for Modular HTGRs, IAEA-TECDOC-1238, Vienna, 21 (2001). 

Compact power conversion system with low cost and high thermal efficiency High-speed gas turbine system with vertical single shaft rotor Design feasibility study has been conducted. R D is required. 

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