Insitu rehabilitation of raw water piping

Conference · Sun Dec 31 04:00:00 EST 1995

OSTI ID:234164

Charest, J A ^[1]; Julius, E P ^[2]

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1. Northeast Nuclear Energy Co., Waterford, CT (United States)
2. Proto Power Corp., Groton, CT (United States)

Insitu type rehabilitation processes are a method used to restore piping integrity for municipalities and commercial industries. In commercial applications this process is used to maintain pressure boundary/structural integrity and to provide a corrosion barrier. The liner consists of a flexible epoxy impregnated felt tube which is inverted and forced down the piping system using a head of water. After the host piping is lined the water is heated to 160 F and the epoxy is cured. This results in an epoxy tube which has many of the same structural capabilities of fiberglass piping and essentially creates a ``Pipe Within A Pipe``. The expected life expectancy in a raw water environment is 50 years. The use of this type system for rehabilitation of nuclear power plant service water systems provides significant cost savings, increases reliability and extends piping life. Northeast Utilities (NU) identified the potential benefits of this process in 1988, as part of their overall service water rehabilitation program at Millstone Unit 2. Specifically, NU was interested in ensuring the continued reliability of the buried service water piping. As this liner had never been used in a safety related system, NU initiated a program to qualify the process for use in a Safety Class 3 raw water systems. This qualification report evaluated the lining to ensure that the presence of the liner or its possible failure modes do not diminish the required flow to safety related components or affect the systems safety function. Based on the above report`s favorable conclusions and economic considerations, the process was utilized on the buried service water headers at Millstone Unit 2 during the 1992 refueling outage. As an end result of this process, 1,200 feet of 24 in. buried Service Water pipe was lined with a seamless .375 in. epoxy impregnated tube, which provides a significant corrosion barrier and enhances the structural and pressure boundary capacity of the system.

• OSTI ID: 234164
• Report Number(s): CONF-9411168--; ISBN 0-87171-444-2
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
22 GENERAL STUDIES OF NUCLEAR REACTORS
AUXILIARY WATER SYSTEMS
BIOLOGICAL FOULING
CORROSION PROTECTION
ENGINEERED SAFETY SYSTEMS
IN-SITU PROCESSING
LINERS
MILLSTONE-2 REACTOR
PERFORMANCE
PIPES
RELIABILITY
REPAIR
SERVICE LIFE
WATER HAMMER
WATER SUPPLY