Document: NRC Regulatory Guide
Document ID: 91c1459d-4ae6-4802-8c6d-e805db860e10
Document Type: regulatory_guide
Title: Post-tensioned Prestressing Systems for Concrete Reactor and Containment (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1221/ML12216A010.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.103
CFR Part: 
CFR Title: 

Content:
was developed in the United States by Stressteel Corporation in cooperation with Howlett Machine Works, is charac- terized by a three-piece slotted wedge cone that grips three strands in its serrated teeth, with a number of wedges in a single anchor plate making up a multistrand tendon of the desired size. As an example, the contain- ment of the Three Mile Island Nuclear Station Unit No. 2 in Pennsylvania uses a Stressteel S/H multistrand system consisting of tendons with 54 1/2-inch, Grade 270K, 7-wire strands per tendon, each tendon develop- ing 2230 kips capacity. The Freyssinet system was named after the French engineer Eugene Freyssinet, who invented the anchorage device in 1939. The original anchorage device was for a wire system only. This is a commonly used commercial system. The anchorage consists of a male conical plug and a female conical recess. The plug, with the wires spaced evenly around its perimeter, anchors the wire by wedge action. As a result of mjjket requirements and subsequent developments, the Freyssinet system now also has available anchorages for strand tendons and other shapes of anchorage devices different from the original one. The same wedge principle for anchoring the tendon is retained, however. Concrete reactor vessels have been built in Europe using the Freyssinet strand system with a maximum tendon capacity of about 2000 kips. The SEEE system was developed in France by the Societe d'Etudes et d'Equipements d'Enterprises. The system features threaded anchorage fittings extruded onto the ends of a group of strands. An anchoring nut is then threaded onto the anchorage fitting and turned **The Delmarva Summit Power Station has been canceled. 1.103-2 tightly against the bearing plate. A tendon is composed of one or several such anchorage fittings on a common bearing plate. Bar Systems. Bar systems use a number of high- tensile-strength steel bars that are bundled into a tendon. 'The bars are made from an alloy steel conforming to ASTM