Inadvertent actuation block valve for a small modular nuclear reactor

An inadvertent actuation block valve for a main valve in an emergency core cooling system of a modular nuclear reactor, the inadvertent actuation block valve comprising:

• a housing having a chamber, an inlet orifice, a reactor reference pressure orifice, and an outlet orifice, the inlet orifice and the outlet orifice being in selective fluid communication via the chamber, and the reactor reference pressure orifice being fluidly isolated from the outlet orifice;
• a disc disposed within the chamber, the disc having a contacting surface disposed adjacent the outlet orifice;
• a spring disposed between the disc and the outlet orifice, the spring biasing the disc away from the outlet orifice;
• a rod located within the chamber and positioned vertically below and adjacent to the disc, the rod being movable within the chamber;
• and
• a bellows sealingly secured to the rod, the bellows configured to contract at a predetermined pressure differential between reactor fluid entering the reference pressure orifice and control fluid entering the inlet orifice, the disc translating vertically upwards when the bellows contracts such that the contacting surface of the disc engages the outlet orifice and isolates fluid communication between the inlet orifice and the outlet orifice,
• the housing comprising:
• a lower housing having a cavity comprising a first section and a second section, the inlet orifice and reactor reference pressure orifice positioned within the lower housing and in fluid communication with the first and second sections of the cavity, respectively;
• and
• an upper housing having a protrusion oriented vertically downwards with respect to a horizontal surface of the upper housing, the protrusion having a hollow space therein defined by a sidewall,
• the first and second sections of the cavity being fluidly isolated from one another such that there is no fluid communication between the first section and the second section, and the protrusion of the upper housing located within the first section of the cavity such that a through hole in the sidewall of the protrusion places the hollow space in fluid communication with the inlet orifice.

An inadvertent actuation block valve for a main valve in an emergency core cooling system of a modular nuclear reactor, the inadvertent actuation block valve comprising:

• a housing having a first chamber, an inlet orifice, a reactor reference pressure orifice, and an outlet orifice, the inlet orifice and the outlet orifice being in selective fluid communication via the first chamber, and the reactor reference pressure orifice being fluidly isolated from the outlet orifice;
• a disc disposed within the first chamber, the disc having a contacting surface disposed adjacent the outlet orifice;
• a spring disposed between the disc and the outlet orifice, the spring biasing the disc away from the outlet orifice;
• a rod extending within the first chamber and positioned vertically below and adjacent to the disc, the rod being movable within the first chamber;
• and
• a bellows sealingly secured to the rod, the bellows configured to contract at a predetermined pressure differential between reactor fluid entering the reference pressure orifice and control fluid entering the inlet orifice, the disc translating vertically upwards when the bellows contracts such that the contacting surface of the disc engages the outlet orifice and isolates fluid communication between the inlet orifice and the outlet orifice;
• wherein the bellows is positioned in a second chamber in the housing and fluidly isolates the control fluid from the reactor fluid within the second chamber, and wherein the control fluid acts on an internal surface of the bellows and the reactor fluid acts on an opposite, external surface of the bellows.