Nuclear Plant Life Extension

As many nuclear plants approach the end of their initial 40 year license period, inspection or replacement of their reactor internals bolts must be considered. This is consistent with the Materials Reliability Program (MRP 227/228) guideline for plant life extension [1,2]. Assurance of the internals structural integrity is essential for continued safe operation of these plants. If there is no suspicion or indication of bolt failure, simple inspection is normally more cost-effective than replacement. Inspection vendors have inspected thousands of internals bolts with conventional and Phased Array UT but different head configurations and bolt capture mechanisms mandate specific qualifications for each bolt type. In some cases, complex bolt and head geometries coupled with counter-bore and locking bar interferences render classical UT inspections difficult or impossible. A range of solutions to inspect reactor internals including these difficult-to-inspect-by-conventional-UT baffle bolts has been developed by several vendors [3]. This presentation references developments to make bolt inspection a relatively quick and easy task through adaptations to the SUSI submarine inspection platform, the extensive UT qualification work suitable for conventional UT plus more recent advanced nonlinear resonant techniques to distinguish between flawed or loose, vs. acceptable bolts where conventional UT cannot be applied. Initial evaluations show that these advanced techniques may have the ability to reliably detect smaller flaws than previously possible with conventional techniques as well as provide information on bolt tightness.

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Challenges in radiation damage: From dynamics of atoms to nuclear plant life management

Radiation Effects and Defects in Solids ◽

10.1080/10420159808229680 ◽

1998 ◽

Vol 144 (1-4) ◽

pp. 311-334 ◽

Cited By ~ 8

Author(s):

A. M. Stoneham ◽

C. A. English ◽

W. J. Phythian

Keyword(s):

Radiation Damage ◽

Nuclear Plant ◽

Life Management ◽

Plant Life

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Section III and Section XI: Integration in the Design Specification and Design Report

Pressure Vessel and Piping Codes and Standards ◽

10.1115/pvp2003-1797 ◽

2003 ◽

Author(s):

John T. Land

Keyword(s):

Power Plant ◽

Pressure Vessel ◽

Life Extension ◽

Design Specification ◽

Plant Life ◽

Fatigue Evaluation

One of the activities of power plant owner’s and equipment providers today is upgrading and/or repair/replacement of original equipment. Plant life extension, and fatigue evaluation are also activities that are being performed routinely. These activities come under the rules and guidance of the ASME Boiler and Pressure Vessel Code, Section XI, whereas, the original equipment generally came under the rules of Section III.

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