Journal of Critical Infrastructure Policy
vanced Research Projects Agency - Energy ( ARPA-E ) has adopted the term Micro Modular Reactor ( MMR ) to refer to modular reactors of any technology that are less than 10 MWe in size ( Zhao 2016 ).
A few SMR , Advanced Reactor , and MMR reactor designs have matured to the point where their developers have formally engaged with the NRC — either via submission of a design certification application ( DCA ), a combined operating license ( COL ) application , or other pre-application discussions . A preliminary review of information made public by five SMR and MMR reactor vendors was conducted to assess whether new reactor designs are progressing towards rNPP capability . The information reviewed was obtained from the developers ’ corporate websites , various publications , and vendor filings with the NRC . Brief design and physical characteristics descriptions , along with images of the proposed reactors / NPPs ( when available ) are presented below . Importantly , the analysis includes a preliminary evaluation of each design ’ s ability to meet the six rPP / rNPP functional requirements listed in Table 1 , and the extent to which the designs incorporate the rNPP-enabling design features summarized in Table 2 .
The results of this preliminary review are summarized in Table 4 and discussed below . 4 All five vendors were “ likely to meet ” functional requirements for three functions ( FRs 2 , 5 , 6 ). At this time , only two vendors were deemed likely to meet all six rNPP Functional Requirements .
NuScale SMR
The NuScale SMR is a thermal spectrum , 200 MWt / 60 MWe , natural circulation-cooled , integral pressurized water reactor ( PWR ). It is considered to be an evolutionary PWR in that it utilizes shortened , but traditional PWR nuclear fuel assembly designs . Each NuScale Power Module™ ( NPM ) vessel ( Figure 4 ) consists of a single reactor together with its integrated steam generator . The NPM vessel is approximately 9 feet ( 2.7 m ) in diameter and 65 feet ( 20 m ) tall . ( Note : the physical sizes of SMR and MMR vessels vary widely and depend on reactor power , the specific NPP functions integrated into the vessel , and the specific technologies employed to accomplish those functions .) Multiple NPMs would be clustered in a single NuScale NPP to deliver power to the Grid in multiples of 60 MWe ( NuScale 2020a ).
4 A few caveats are in order on the discussion that follows . First , it is not a technical maturity / technology readiness ( to deploy ) ( DOD 2011 ) assessment of the reactor systems described . At the time of this writing , the systems discussed are at differing levels of technical maturity . The NuScale SMR is the most mature design concept at present . Some of the plant designs discussed are more likely to change than others . Second , the analysis is based solely on a review of publicly available information . There is much more public domain information available at present for some designs than others . Finally , the analysis was conducted without assistance from or the direct participation of the vendors / developers of these reactors . For these and other reasons , the results presented , and conclusions reached , are necessarily preliminary in nature and are subject to change . Readers are encouraged to examine the information available to them at the time that they review these exploratory findings in order to confirm their accuracy .
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