GT-MHR plant

A GT-MHR plant consdsts of one or more identical GT-MHR power units where each unit consists of a GT-MHR power module (Figure 6.6.1.) plus its support systems. Each power module is housed in a below grade reinforced concrete structure which serves as an independent, vented, low pressure confinement. 

Preliminary economic assessments indicate the projected levelized busbar generation cost for the four module "equilibrium" GT-MHR plant at 600 MW(t) per module is about 35 mills/kWh (in 1994). The "equilibrium" plant reflects learning cost reductions from construction of several previous plants. This is a decrease of over 35% in busbar costs compared to the early 1980s designs of the 350 MW(t) steam... 

A construction period of <3 years for the first module of a reference 4-module GT-MHR plant with successively shorter periods for sequentially constructed follow-on modules. 

The construction period required for the first module of the N -of-a-kind standardized GT-MHR plant is estimated to be -3 years based on experience information from serial construction of identical design nuclear plants (in France as well as in the USA), and assuming the use of the 10CFR52 one-step licensing process as well as modern (computerized) plant construction practices. The GT-MHR N -of-a-kind plant 20 year levelized busbar generation cost is projected to be 3.1 cents/kWh (2003 US ) including capital, O M, fuel, waste disposition and decommissioning. 

A comparison of resource requirements and environmental impacts between a 4-module GT-MHR plant and a large pressurized water reactor (PWR) is provided in Table XV-3. 

Most of the operating data for the PH-MHR are the same as for the GT-MHR. GT-MHR has a capacity of 1.145 MWe. The electricity-equivalent size of the 4-unit plant is adjusted to reflect the lower efficiency of the PH-MHR a 2.400 MWth plant operating at 42% efficiency would have an electric-equivalent rating of 1.008 MWe. 

A follow-up design is given in the GT-MHR (Modular Helium Reactor) (see also section 4.7.2.) with a higher power output of 600 MW(th). A standard plant is planned consisting of four of those units. Helium inlet/outlet temperatures are 485 and 850 °C, respectively. The cycle efficiency is predicted to be 47 % [51]. Follow-on evaluations which need to be done include the study of transient response of plant components to normal and off-normal events, impact of turbine contamination, and confirmation of plant efficiency [47]. 

GT--MHR project is a joint Russian-American design of the nuclear power plant with direct gas turbine cycle. 

McDonald, C. F., R. J. Orlando, and G. M. Cotzas, Helium Turbomachine Design for GT-MHR Power Plant, GA-A21720, July 1994, Presented at the ASME International Joint Power Generation Conference, October 8-13,1994, Phoenix, AZ, USA. 

Now, power generation plant named GT-MHR which consists of 600MWth HTGR connected with Power Conversion Module (closed cycle regenerative gas turbine system contained within a single vessel) is under development by the US. and Russian cooperation. 

A comparative cost analysis was performed for the AHTR by scaling individual subsystem costs for either the GT-MHR or the S-PRISM. The result is that the AHTR overnight capital cost (without contingency) is estimated to be approximately 820 /kW(e) (2002 dollars), which is 50-55% of the S-PRISM and GT-MHR costs for similar total output. This is a consequence of economy of scale. The AHTR electrical output is approximately four times that of these other reactors but with a similar plant size and complexity. Relative to light-water reactors, the AHTR should be more economical because of the higher power conversion efficiency, low-pressure containment, and absence of active safety systems. 

Power conversion system. The cost of the AHTR power conversion system is scaled based on PCU power densities from detailed UCB design studies shown in Table 8.2, from the cost of a set of GT-MHR PCUs capable of producing 1145 MW(e), using a scaling exponent of 0.86. The PCU costs are scaled further by a factor of 0.9 to account for the fact that they are not nuclear-grade equipment in the AHTR. The costs of the electrical plant and the heat rejection equipment are scaled with electrical power (0.86 exponent) and thermal heat rejection (also 0.86 exponent), respectively. 

GAS TURBINE MODULAR HELIUM REACTOR (GT-MHR) POWER PLANT 6.6.1. Basic objectives and features... 

Each GT-MHR power unit has a design rating of 600 MWt/286 MWe. (The rating of initial units is planned to be limited to 550 MWt/262 MWe to provide design margin). One or more standardized power units are used to form plants with ratings up to 1150 MWe while maintaining the passive safety features of the MHR. 

The GT-MHR uses a direct Brayton (gas turbine) cycle for the generation of electricity. As a result, the complex and expensive balance of plant systems required by steam cycle plants are not needed for the GT-MHR. 

The simplicity of the GT-MHR is reflected in its instrumentation systems Total visibility of plant conditions, and all control and protection actions are provided with a relatively low number of instrumentation channels. Clear and concise operator information is provided. The passive safety of the reactor, its slow response, and the neutronic transparency and the absence of phase changes in the gas coolant eliminate many of the human factors complications found in other reactors. 

MHR thermal discharge to the environment is low, due to the system s high efficient The GT-MHR is free of the emissions associated with burning fossil fuels Radioactive emissions ifom helium-cooled reactor plants are lower than those fi om comparably sized coal-fired plants... 

The GT-MHR design directly couples the reactor with a turbogenerator in a closed helium Brayton cycle to produce electricity with 48% net plant efficiency. This high efficiency and the expansion of the power output to 600 MW(t) within the existing GT-MHR physical envelope results in a substantial reduction in the busbar power costs compared to the steam cycle modular helium reactors. The power generation costs are forther reduced by the simplified operation and maintenance required of the gas turbine plant, as compared to the steam cycle plant with its much more complicated balance of plant. 

Germany - Oberhausen 2 - 1975 - 1987 - This 50 MW electric turbine plant represented the evolutionary step from fossil-fired gas turbines with air as the working fluid towards the realization of nuclear powered helium gas turbines. Helium was used as the working fluid in a closed-cycle process for electricity and heat production. The plant incorporated heat exchangers (recuperator, precooler, intercooler) of comparable size to those required for a 600 MW thermal GT-MHR. 

Tables 5.2 and 5.3 show an outline of GT-MHR nominal plant design parameters and GT-MHR-coated particle fuel design parameters, respectively.

The GT-MHR produces less heavy metal radioactive waste per unit energy produced because of the plant s high thermal efficiency and high fuel burnup. Similarly, the GT-MHR produces less total plutonium and Pu-239 (materials of proliferation concern) per unit of energy produced. 

Being a small sized reactor plant, the BN GT-300 has certain similarities in the design philosophy, design approaches and certain technologies with other SMRs, such as VBER-300 [XVm-2, XVm-3] VK-300 [XVm-2, XVm-3] GT-MHR [XVm-3] KLT-40 [XVm-2] SVBR-75/100 [XVm-6, XVm-7] and others [XVIH-S, to XVIH-IO]. 

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