The primary objective of this report is to evaluate materials degradation issue unique to the operational environments of LWSMR. Concerns for specific primary system components and materials are identified based on the review of design information shared by mPower and NuScale. Direct comparisons are made to materials issues recognized for advanced large PWRs and research activities are recommended as needed. The issues identified are intended to improve the capability of industry to evaluate the significance of any degradation that might occur during long-term LWSMR operation and by extension affect the importance of future supporting R&D.The evaluations documented in this report highlight that neither large advanced PWR designs, nor LWSMR primary system designs, introduce significant changes in material selection or fabrication processes from those being applied in Gen. II reactor plant component repairs and replacements. Although differences in configuration introduced by LWSMRs create some unique circumstances that warrant study, in most areas the new materials R&D needed to support the application is not fundamentally distinct from current LWR research programs, but rather represents a possible extension of these programs. To address LWSMRs, R&D plans should be reviewed and adjusted as needed to ensure the relevant design configurations, environmental conditions and performance expectations are addressed.An example of a new design configuration that suggests a need for materials R&D is the use of a helical coil steam generator with primary coolant flowing on the tube OD and secondary coolant boiling occurring on the tube ID surfaces. In this case, the broad areas of R&D suggested relate to ensuring no SCC vulnerabilities are introduced by fabrication processes needed for the helical coil tube bundle and the need for improvements in thermo-hydraulic modeling capabilities. A less obvious example of a new design configuration relates to vessel fabrication practices. Vessel fabrication will certainly be more complicated due to the integration of all of the primary system components from a traditional PWR into a single vessel enclosure.Examples of new environmental exposure conditions include reactor vessel fluence and CRD operating environment. The smaller diameter and lower operating pressures used by LWSMR designs allow for significantly thinner vessel shells, but with higher EOL neutron fluence. As a consequence, significant radiation damage occurs through a greater fraction of the wall thickness. With regard to CRDs and CRD penetrations, some LWSMRs will locate the CRDs at the top of the integrated vessel, causing them to be exposed to steam at higher pressurizer temperatures.As significant changes in material selection are unlikely for LWSMR designs, research to resolve key materials degradation concerns identified for large advanced PWRs remains of high importance and expanded activities are needed in many areas. Significant benefit for LWSMRs can be gained by R&D to characterize the effects of component fa...

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