Non-LW-SMR

Non-LW-SMRs can be considered in the category of Generation IV (Gen-IV) reactors in that they are highly economical with improved passive safety and reduced levels of radioactive waste. 

However, most of the non-LW-SMRs are in the early phase of development and are therefore unable to easily inherit significant licensed features of other commercial Gen-IV reactors because even these reactors are still in the development phase. Even though LW-SMRs are relatively similar to each other, Gen-IV designs include a wide range of design varieties, such as coolant types, control systems, fuels, etc. 

Most of LW-SMR vessels are compact and integrated designs, which contain aU the major RCSs along with SGs and an integral PRZ. Typical outlet temperatures are at around 300°C in LW-SMRs, which are much lower compared to ADV SMRs (non-LW-SMRs) as shown in Table 20.1. Outlet temperature could range from about 500°C to 1000°C. 

Some of the non-LW-SMRs offer load following capability even though most of the LW-SMRs work with base load. The following needs can be met with load following capability of some SMRs (IAEA, 2002 NRC, 2014a Kumar et al., 2012) ... 

High core outlet temperature of coolant can only be provided by the non-LW-SMRs. Therefore, N = non-LW-SMRs can be used to produce high temperature steam for facilities/factories and to generate electricity with high efficiency. 

Typical 17 x 17 fuel assemblies are used in LW-SMRs (Table 20.3). The differences between fuels assemblies used in LW-SMRs and commercial LWRs (such as API000) are the height and fuel cycle length of the fuel. Most of the non-LW-SMRs utUize unique fuel designs, as shown in Table 20.3. 

LW-SMRs generally employ 5% fuel enrichment, and non-LW-SMRs can have much higher fuel enrichment value (Table 20.3). For example, Hyperion uses about 20% enriched U-235... 

This chapter compares selected LW and non-LW-SMRs in respect to nuclear reactors, fuels, containment, and ECCS. Even though there is no clear winner in this comparison, the following conclusions are highlighted ... 

S s safety system has several active, passive, and inherent safety features. Especially advanced inherent safety feature and 30 years refueling frequency makes 4S different than other non-LW-SMRs. 

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