Reactor process water (PW) piping inspections, 1984--1990 [electronic resource].
- Washington, D.C. : United States. Dept. of Energy, 1990.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- 3 pages : digital, PDF file
- Additional Creators:
- Westinghouse Savannah River Company
United States. Department of Energy
United States. Department of Energy. Office of Scientific and Technical Information
- In July 1983, the NRC ordered the shutdown of five boiling water reactors (BWR`s) because of concerns about reliability of ultrasonic examination for detecting intergranular stress corrosion cracking (IGSCC). These concerns arose because of leaking piping at Niagara Mohawk`s Nine Mile Point which was attributed to IGSCC. The leaks were detected shortly after completion of ultrasonic examinations of the piping. At that time, the Dupont plant manager at Savannah River (SR) directed that investigations be performed to determine if similar problems could exist in SR reactors. Investigation determined that all conditions believed necessary for the initiation and propagation of IGSCC in austenitic stainless steel exist in SR reactor process water (PW) systems. Sensitized, high carbon, austenitic stainless steel, a high purity water system with high levels of dissolved oxygen, and the residual stresses associated with welding during construction combine to provide the necessary conditions. A periodic UT inspection program is now in place to monitor the condition of the reactor PW piping systems. The program is patterned after NRC NUREG 0313, i.e., welds are placed in categories based on their history. Welds in upgraded or replacement piping are examined on a standard schedule (at least every five years) while welds with evidence of IGSCC, evaluated as acceptable for service, are inspected at every extended outage (15 to 18 months). This includes all welds in PW systems three inches in diameter and above. Welds are replaced when MSCC exceeds the replacement criteria of more than twenty percent of pipe circumference of fifty percent of through-wall depth. In the future, we intend to perform flow sizing with automated UT techniques in addition to manual sizing to provide more information for comparison with future examinations.
- Published through SciTech Connect.
32. meeting of the Weapons Agencies Nondestructive Testing Organization (WANTO),Aiken, SC (United States),27-29 Nov 1990.
Elder, J.B.; Sprayberry, R.E.; Ehrhart, W.S.; Vande Kamp, R.W.
- Funding Information:
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