The Fisher SS-84PSV4 valve is the pressurizer spray valve for use in third generation PWR nuclear generating stations.
The NPS 4x3 valve body has NPS 4 buttweld ends with 3 inch Fisher Vee-Ball internal trim, which operates against a spring-loaded sleeve seal. This valve contains several enhanced features compared to the original SS-84 designs, which operated in previous PWR Reactors.