Tentative Thickness for Torispherical and Ellipsoidal ASME Section III Class 1 Heads

Class 1 nuclear vessel heads with ellipsoidal or torispherical geometries offer several advantages over spherical heads. They shorten the overall height of the vessel, reduce internal volume, lower the vessel center of gravity, and are more economical. At present Section III only offers tentative thickness formulas for spherical heads in NB-3324 [1]. This paper proposes the addition of tentative thickness formulas for Class 1 torispherical and ellipsoidal heads. A large family of finite element analyses over a practical range of vessel geometries and pressures is used to establish the new thickness equations.