Seismic attenuation system for a nuclear reactor

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; and

an 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; and

wherein 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; and

wherein 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; and

wherein 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; and

wherein 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; and

wherein 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; and

wherein 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; and

wherein 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.