PWR relief valves

[valvehowker]

Can someone explain me the over pressure protection methods for the new generation of PWR from Westinghouse and Areva.
Is there a motorised valve fluid release controlled from the plant control system for initial protection, with an ultimate backstop safety valve(s)?

Are the ultimate safety valves pilot operated or direct spring operated relief valves? Which are the valve manufacturers typically specified by the plant designer for these and does the nuclear regulator generally have a contolling input on the valve types used in different countries?.

Kind regards
Bill

 

[vpl]

Bill

I'm not sure the final design details have been worked out to the detail that could answer your question. I'm relatively certain that there have not been any decisions made about valve manufacturer's.

Additionally, at least for "old generation" PWR's there are both "spring" safety valves and pilot operated "relief" valves.

In regard to the "nuclear regulator's" part of your question: in the US, the regulator does not care what manufacturer is used. In regard to the valve type (i.e., pilot versus spring), the regulator would only review the design to determine if the licensee meets the standard review plan. You can find the standard review plan on the NRC's web site (

http://www.nrc.gov)by

select the electronic reading room, then collections of documents by type, then NUREGs, then NUREG 0800.

Patricia Lougheed

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