NSE - Nuclear Science & Engineering at MIT


Compact pressurized water reactors

The integral PWR design is the leading technology for several Small Modular Reactor (SMR) concepts under development. CANES researchers have investigated ways to allow the SMRs to be more compact, and hence potentially more economic. Two innovative features are the use of Printed Circuit Heat Exchangers (PCHE) as steam generators and internally and externally cooled annular fuel. Performance of the compact PWR was assessed with consideration of both steady state and transient conditions. Use of PCHE technology alone showed the possibility of reducing the pressure vessel radius and height by 25% and 15%, respectively. The vessel is one of the most expensive components and is the limiting factor in factory manufacturability. Issues that remain to be addressed are validation of the steam generator performance and maintenance, sizing of internal pumps, and reliability of internal control rod drives. Recently, DOE allocated $450 million for SMR development in collaboration with industry, and $6 million dollars for investigation of the integral LWR with PCHE technology.


  1. Shirvan K., Hejzlar P. Shatilla Y. and Kazimi M.S., “Enhancing the Power Density of IRIS by Compact Steam Generators,” Transactions of the American Nuclear Society, Vol. 100, New York, pp. 567–568, 2009.
  2. Shirvan K. Hejzlar P., and Kazimi M.S., ”The Design of a Compact Vessel Integrated LWR,“ Proceedings of International Congress on Advances in Nuclear Power Plants (ICAPP ’10), San Diego.
  3. Shirvan K., Hejzlar P., and Kazimi M.S., “The Design of A Compact Integral Medium Size PWR,” Nuclear Engineering and Design vol. 243, pp. 393–403, Feb 2012.

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