Patent Number: 
Section: claims

1. A nuclear steam supply system comprising:a containment enclosing a primary loop of the nuclear steam supply system within an interior thereof;a reactor vessel supported within a reactor well within a lower interior of the containment, the reactor well having walls that substantially surround a lower portion of the reactor vessel;a vertical shield wall that extends up from an upper portion of the reactor well walls and substantially encircles an upper portion of the reactor vessel and extends vertically above the reactor well substantially to an elevation of an operating deck;a missile shield capping a top of the vertical shield wall; andwherein the shield wall includes at least one air inlet door located along at least a portion of a lower section of the shield wall, the inlet door being configured to be normally closed during reactor operation, but is configured to be opened during an outage to enable cooling air flow along an interior of the shield wall, and an outlet door located along at least a portion of an upper section of the shield wail, below the operating deck, the outlet door being configured to be normally closed during, reactor operation, but is configured to be opened during an outage to enable cooling air flow along the interior of the shield wall. 2. The nuclear steam supply system of claim 1 including a plurality of the outlet doors spaced circumferentially around. the upper section of the shield wall. 3. A nuclear steam supply system comprising:a containment enclosing a primary loop of the nuclear steam supply system within an interior thereof;a reactor vessel supported within a reactor well within a lower interior of the containment the reactor well having walls that substantially surround a lower portion of the reactor vessel;a vertical shield wall that extends up from an upper portion of the reactor well walls and substantially encircles an upper portion of the reactor vessel and extends vertically above the reactor well substantially to an elevation of an operating deck;a missile shield capping a top of the vertical shield wall; andwherein the shield wall includes at least one air inlet door located along at least a portion of a lower section of the shield wall, the inlet door being configured to be normally closed during reactor operation, but is configured to be opened during an outage to enable cooling air flow along an interior of the shield wall and wherein the inlet door has a neutron absorbent panel. 4. The nuclear steam supply system of claim 3 wherein the neutron absorbent panel is removeably attached to the inlet door with fasteners. 5. The nuclear steam supply system of claim 3 wherein the neutron absorbent panel is formed from a metal can filled with boro-silicate concrete. 6. A nuclear steam supply system comprising:a containment enclosing primary loop of the nuclear steam supply system within an interior thereof:a reactor vessel supported within a reactor well within a lower interior of the containment, the reactor well having walls that substantially surround a lower portion of the reactor vessel:a vertical shield wall that extends up from an upper portion of the reactor well walls and substantially encircles an upper portion of the reactor vessel and extends vertically above the reactor well substantially to an elevation of an operating deck;a missile shield capping a top of the vertical shield walk; andwherein the shield wall includes at least one air inlet door located along at least a portion of a lower section of the shield wall, the inlet door being configured to be normally closed during reactor operation, but is configured to he opened during an outage to enable cooling air flow along an interior of the shield wall and wherein the containment has a polar crane with an main and auxiliary hook and the shield wall is constructed in sections with substantially each section having a weight that is no heavier than can be lifted by the auxiliary hook.