In a letter to NuScale Power, the Nuclear Regulatory Commission responded to the company’s draft standard design approval application (SDAA) for its small modular reactor design by identifying “several challenging and/or significant issues that could be focus areas for the SDAA acceptance and/or safety review.” The letter described the findings of the NRC’s preapplication readiness assessment and recommended NuScale’s “continued engagement” on a number of topics of concern before finalizing the SDAA.