The primary purpose of the material review board is to

The primary purpose of the Material Review Board (MRB) is to review and determine the appropriate disposition of nonconforming products. The MRB evaluates the nonconformities, decides whether the products can be reworked, used as-is, or must be scrapped, and ensures that corrective actions are implemented to prevent recurrence.

References:

"The Certified Quality Engineer Handbook" by Connie M. Borror.

ASQ Glossary: Material Review Board (MRB)