10 CFR § 217.35 - Extension of priority ratings.
(a) A person must use rated orders with suppliers to obtain items or services needed to fill a rated order. The person must use the priority rating indicated on the customer's rated order, except as otherwise provided in this part or as directed by the Department of Energy. For example, if a person is in receipt of a DO-F1 rated order for an electric power sub-station, and needs to purchase a transformer for its manufacture, that person must use a DO-F1 rated order to obtain the needed transformer.
(b) The priority rating must be included on each successive order placed to obtain items or services needed to fill a customer's rated order. This continues from contractor to subcontractor to supplier throughout the entire procurement chain.