# 52.55 Duration of certification.(a) Except as provided in paragraph (b) of this section, a standard design certification issued under this subpart is valid for 40 years from the date of issuance.(b) A standard design certification continues to be valid beyond the date of expiration in any proceeding on an application for a combined license or an operating license that references the standard design certification and is docketed either before the date of expiration of the certification, or, if a timely application for renewal of the certification has been filed, before the Commission has determined whether to renew the certification. A design certification also continues to be valid beyond the date of expiration in any hearing held under § 52.103 before operation begins under a combined license that references the design certification.(c) An applicant for a construction permit or a combined license may, at its own risk, reference in its application a design for which a design certification application has been docketed but not granted.[72 FR 49517, Aug. 28, 2007, as amended at 90 FR 28873, July 2, 2025]