The Design Features of Integrated Modular Water Reactor (IMR)

Small-to-medium-sized (300–600MWe) reactors are required for the electric power market in the near future (2010–2030). The main theme in the development of small-to-medium-sized reactor is how to realize competitive cost against other energy sources. As measures to this disadvantage, greatly simplified and downsized design is needed. From such point of view, Integrated Modular Water Reactor (IMR), which electric output power is 350 MWe, adopts integrated and high temperature two-phase natural circulation system for the primary system. In this design, main coolant pipes, a pressurizer, and reactor coolant pumps are not needed, and the sizes of a reactor vessel and steam generators are minimized. Additionally, to enhance the economy of the whole plant, fluid system, and Instrumentation & Control system of IMR have also been reviewed to make them simplest and smallest taking the advantage of the IMR concept and the state of the art technologies. For example, the integrated primary system and the stand-alone direct heat removal system make the safety system very simple, i.e., no injection, no containment spray, no emergency AC power, etc. The chemical and volume control system is also simplified by eliminating the boron control system and the seal water system of reactor coolant pumps. In this paper, the status of the IMR development and the outline of the IMR design efforts to achieve the simplest and smallest plant are presented.

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Generation-IV Multi-Application Small Light Water Reactor (MASLWR)

10th International Conference on Nuclear Engineering, Volume 2 ◽

10.1115/icone10-22435 ◽

2002 ◽

Cited By ~ 6

Author(s):

S. Michael Modro ◽

James Fisher ◽

Kevan Weaver ◽

Pierre Babka ◽

Jose Reyes ◽

...

Keyword(s):

Natural Circulation ◽

Thermal Power ◽

Heat Removal ◽

Steam Pressure ◽

Light Water Reactor ◽

Primary System ◽

Light Water ◽

Water Reactor ◽

System Pressure ◽

Environmental Laboratory

The Idaho National Engineering and Environmental Laboratory (INEEL), Nexant Inc. and the Oregon State University (OSU) have developed a Multi-Application Small Light Water Reactor (MASLWR) concept. The MASLWR is a small, safe and economic natural circulation pressurized light water reactor. MASLWR reactor module consists of an integral reactor/steam generator located in a steel cylindrical containment. The entire module is to be entirely shop fabricated and transported to site on most railways or roads. Two or more modules are located in a reactor building, each being submersed in a common, below grade cavity filled with water. For the most severe postulated accident, the volume of water in the cavity provides a passive ultimate heat sink for 3 or more days allowing the restoration of lost normal active heat removal systems. MASLWR thermal power of a single module is 150 MWt, primary system pressure 10.5 MPa, steam pressure 1.52 MPa and the net electrical output is 35–50 MWe.

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General Overview of CVCS Design for the TSN Project

18th International Conference on Nuclear Engineering: Volume 6 ◽

10.1115/icone18-29248 ◽

2010 ◽

Author(s):

Antonio Ciriello ◽

Man Liu

Keyword(s):

Nuclear Power ◽

Power Plants ◽

Nuclear Power Plants ◽

Water Injection ◽

Reactor Design ◽

Auxiliary System ◽

Volume Control ◽

Primary System ◽

Reactor Coolant ◽

Design Concepts

This paper resumes the results of the collaboration between AREVA and CNPDC during the past two years for performing and achieving the basic design of EPR™ reactor CVCS system for the TSN NPP. The CVCS (Chemical and Volume Control System) is an essential auxiliary system of the PWR technology based nuclear power plants all around the world. In the EPR™ reactor design, as it is also in similar nuclear power plants, this auxiliary system has well determined functions, which are: reactivity control, reactor coolant volume control, coolant chemistry control, primary system main pumps seal water injection as well as the pressurizer auxiliary spray regulation for the Reactor Coolant System. In the EPR™ reactor design, the CVCS is mainly an operational system and only some valves and instrumentations take part at some specific safety functions, (e.g. Reactivity Control, Containment of Radioactive Substances). In the first part of this paper a general introduction to the EPR™ reactor CVCS technology, including the related safety functions and detailed operational functions of CVCS, is presented. In the TSN EPR™ reactor CVCS design, the system is divided into eight sections, (defined from RCV1 to RCV8). The corresponding detailed description of these sections, including their functions, structure and main components, as they have been implemented in the EPR™ reactor CVCS design for the TSN NPP, is then presented in the second part of this paper. In addition some specific design features for EPR™ reactor CVCS system for the TSN NPP, such as the hydrogenation station technology, are also focused in this paper. The reference power plant, concerning the CVCS design, for the TSN NPP is the FA3 NPP, but different design concepts have been implemented in the TSN NPP with regards to the coolant purification section (RCV2), and the coolant filtering in the reactor coolant pumps seal injection and leak-off lines.

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Thermal Hydraulic Analysis Due to the Changes in Heat Removal for Advanced Heavy Water Reactor

12th International Conference on Nuclear Engineering, Volume 3 ◽

10.1115/icone12-49147 ◽

2004 ◽

Author(s):

B. Chatterjee ◽

A. Srivastava ◽

D. Mukhopadhyay ◽

P. Majumdar ◽

H. G. Lele ◽

...

Keyword(s):

Heavy Water ◽

Natural Circulation ◽

Heat Removal ◽

Reactor Power ◽

Circulation System ◽

Feed Water ◽

Set Point ◽

Water Reactor ◽

Heavy Water Reactor ◽

Pressure Controller

Advanced Heavy Water Reactor is natural circulation light water cooled and heavy water moderated pressure tube type of reactor. Changes in heat removal by primary heat transport system of a reactor have significant impact on various important system parameters like pressures, qualities, reactor power and flows. Increase in heat removal leads to Cooldown of the system subsequently reducing pressure, void increase and changes in power and flows of the system. Decrease in heat removal leads to warm-up of the system subsequently raising pressure, void collapse, and changes in power and flows of the system. The behaviour is complex as system under consideration is natural circulation system. Causes for events under category of increase in heat removal are mainly malfunctioning of feed water heaters, Isolation Condensers (IC) inlet valves and controllers. These events lead to cooldown of system and addition of positive reactivity addition due to void collapse. Various events considered are Feed Water System malfunctions that result in decrease in feed water temperature, inadvertent opening of IC valve, Failure of PHT Pressure Control System and Decrease in pressure controller set point to 67 bars. Causes for events under category of decrease in heat removal are mainly malfunctioning of controllers, feedwater valves and operating events like turbine trip. Functioning of passive cooling system and different valves play important role for these events. These events lead to increase in system pressure. Various events considered are Loss of normal feed water flow (multiple trains), Turbine trip without bypass without IC, Turbine trip without bypass with IC, Turbine trip with bypass without IC, Increase in PHT pressure controller set point, Decrease in level controller set point, Turbine Trip with setback, Decrease in steam flow and Class IV power failure. Changes in the system voids and pressures as a result of change in the heat removal leads to complex reactivity feedback due to coolant temperatures, void fraction and fuel temperatures. These changes in the reactor power together with void distribution change affect two-phase natural circulation flow. This paper brings out these aspects. It discusses descretisation of the system and brings out various design aspects. In this paper summary of analysis for each event is presented, various modeling complexities are brought out, evaluation of acceptance criteria is made and design implications of each event is discussed.

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Experimental Investigations on the Isolation Condenser Performance in Integral Test Loop

Volume 3: Thermal Hydraulics; Instrumentation and Controls ◽

10.1115/icone16-48600 ◽

2008 ◽

Cited By ~ 1

Author(s):

Manish Sharma ◽

D. S. Pilkhwal ◽

P. K. Vijayan ◽

D. Saha

Keyword(s):

Heavy Water ◽

Cooling System ◽

Water System ◽

Heat Removal ◽

Experimental Investigations ◽

Feed Water ◽

Integral Test ◽

Water Reactor ◽

Test Loop ◽

Heavy Water Reactor

The proposed Advanced Heavy Water Reactor (AHWR) is a light water cooled and heavy water moderated pressure tube type boiling water reactor based on natural circulation. AHWR adopts several passive concepts with a view to simplify the design and to enhance safety and public acceptability. One such feature is passive decay heat removal using isolation condenser (IC) system during a station blackout. A scaled Integral Test Loop (ITL) was set up in BARC to simulate the overall system behavior studies for Advanced Heavy Water Reactor (AHWR). This facility simulates the Main Heat Transport System (MHTS), Emergency Core Cooling System (ECCS) and Isolation Condenser system (ICS) system, Feed Water System (FWS) and the associated controls. Power to volume scaling philosophy has been adopted for the design of the ITL systems. To evaluate the performance of IC, experiments have been carried out in ITL. The test results have been simulated using RELAP5/ MOD3.2. This paper deals with the experiments conducted, nodalization scheme adopted for ITL in RELAP5/MOD 3.2 simulation, transient predictions made and the results obtained in detail.

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Experience in Chemical Decontamination of PWR Systems and Components

ASME 2009 12th International Conference on Environmental Remediation and Radioactive Waste Management, Volume 2 ◽

10.1115/icem2009-16274 ◽

2009 ◽

Author(s):

Claude Steinkuhler ◽

Koen Lenie ◽

Reginald Coomans

Keyword(s):

Critical Path ◽

Heat Removal ◽

Volume Control ◽

Pressurized Water ◽

Coolant Pump ◽

Regenerative Heat ◽

Reactor Coolant ◽

Chemical Decontamination ◽

Waste Production ◽

Water Reactors

Tecnubel has recently performed various chemical decontamination of French and Belgian Pressurized Water Reactors (PWR) systems and components. The purpose of this paper is to present and compare these experiences. The objectives of these operation were the reduction of the general surface contamination together with the elimination of hot spots in Residual Heat Removal Systems (RHRS), Chemical and Volume Control Systems (CVCS) and Reactor Coolant Pumps (RCP). This reduction of contamination leads to the reduction of dosimetry to the maintenance personnel and allows the works on critical equipment. An additional challenge for three of these projects lay in the execution of a complicated operation on the critical path of a reactor refueling shutdown. The chemical decontamination were performed by circulating an adequate fluid in the systems or around the components. Since the contamination was generated at hot conditions during power operation, a redox attack on the surface was necessary. The EDF systems and components were decontaminated using a qualified EDF process of the EMMAC family. The Reactor Coolant Pump from the Belgian PWR was treated with the NITROX process, qualified by Westinghouse. The functions required by the decontamination system were very diverse and therefore an existing decontamination loop, which was previously developed for the decontamination of small circuits, was re-developed and adapted for bigger volumes by DDR Consult and Tecnubel. The results of five decontamination are presented and detailed in terms of efficiency and waste production. These projects were: the chemical decontamination of the RHRS of Flamanville 1 NPP, of the CVCS non regenerative heat exchanger at St Laurent des Eaux NPP, of the RHRS and CVCS of Bugey 2 NPP and of two RCP at the Westinghouse Belgian Service Center.

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