Patent Number: 
Section: claims

1. A system for attenuating seismic forces in a nuclear reactor assembly comprising:a containment vessel configured located above a support surface;a reactor pressure vessel mounted within the containment vessel to house a nuclear reactor core; andan attenuation device integrally operatively coupled to the containment vessel and located along a longitudinal centerline of the reactor pressure vessel to attenuate seismic forces transmitted from the support surface to the reactor pressure vessel via the containment vessel in a substantially transverse direction to the longitudinal centerline;wherein the attenuation device includes an integrated vertical key portion and an integrated lateral support portion, the integrated vertical key portion extending upwardly in a substantially vertical direction from an inner surface of the containment vessel and the integrated lateral support portion extending downwardly in a substantially vertical direction from an outer surface of the containment vessel;wherein the integrated vertical key portion is to engage a recess of the reactor pressure vessel to provide lateral support to the reactor pressure vessel; andwherein the integrated lateral support portion is to engage between at least a pair of stops extending upwardly from the support surface to receive the seismic forces transmitted from the support surface. 2. The system of claim 1, wherein the attenuation device is configured to provide for a thermal expansion of the reactor pressure vessel within the containment vessel. 3. The system of claim 2,wherein the integrated vertical key comprises a substantially vertical protrusion; andwherein the recess comprises a vertical clearance to account for a thermal expansion of the reactor pressure vessel along the longitudinal centerline. 4. The system of claim 3,wherein the vertical protrusion comprises a diameter; andwherein the vessel recess further comprises an annular-shaped clearance to account for the thermal expansion of the diameter of the vertical protrusion. 5. The system of claim 1,further comprising a support structure located in an upper half of the containment vessel and configured to support the reactor pressure vessel within the containment vessel;wherein the attenuation device is located in the bottom half of the containment vessel. 6. The system of claim 5,wherein a majority of a weight of the reactor pressure vessel is supported by the support structure; andwherein substantially none of the weight of the reactor pressure vessel is supported by the attenuation device. 7. The system of claim 1,wherein the containment vessel comprises a cylindrical-shaped support skirt that contacts the support surface;wherein a bottom head of the containment vessel is located some distance above the support surface; andwherein the support skirt comprises through-holes configured to allow coolant to flow through the support skirt and contact the bottom head. 8. The system of claim 1,wherein the integrated vertical key comprises a vertical post located along the longitudinal centerline of the containment vessel; andwherein the vertical post is inserted into the recess of the reactor pressure vessel. 9. The system of claim 8,wherein the containment vessel comprises a bottom head; andwherein the vertical post extends upward from the bottom head of the containment vessel into the recess associated with the reactor pressure vessel. 10. The system of claim 9,wherein the integrated lateral support may be configured to contact the at least the pair of stops without directly contacting the support surface.