Operational Reactor Safeguard Examination
An Operational Reactor Safeguard Examination (ORSE) is an examination conducted by senior United States Navy personnel on board U.S. Navy nuclear-powered ships, specifically supercarriers and submarines. The purpose of an ORSE is to ensure that the engineering (submarines) or reactor (aircraft carriers) department of a nuclear-powered vessel is operating their reactor(s) in a safe manner. The exam also ensures the readiness of the engineering department to safely respond to nuclear power plant casualties.
The ORSE board is made up of 3 junior board members (prior Engineers/Reactor Officers) and a senior board member (a prior commanding officer) Nuclear Propulsion Examining Board, or NPEB.
An ORSE is scheduled during an underway period, typically towards the end of a deployment. There are a few surprise ORSE's when the boat or ship is given only a few days of notice. The first task an ORSE board is to review all of the ship's records from the date of the most recent ORSE. During the review of records, the engineering department takes a written exam. After the review, a battery of intense simulation drills will begin. On submarines, each of the 3 watch sections stands one drill watch, is casualty assistance team for another and finally drill monitors for a third. This drill period can last up to 24 hours. After the drills, oral interviews test the department's level of knowledge. Additionally, there are monitored evolutions to evaluate the department's ability to perform selected maintenance items. A typical ORSE lasts for 3 days and the department gets little, if any, sleep for the entire exam.
The purpose of ORSE is to ensure that a ship's engineering or reactor department can respond to any casualty, and is properly following all procedures for operating and maintaining the propulsion plant. Failure to pass ORSE has strong consequences including probable relief of the ship's commanding officer and Engineer/Reactor Officer.  All ORSE failures automatically and immediately result in removal of the ability to operate the reactor.
- Associated Press (2007-10-25). "U.S. Navy Fires Sub Commander Over Nuke Safety Issue". Fox News.