SeqUOyah UnitS 1 and 2 (SOddy-daiSy, tn, aUgUSt 1985 tO nOvember 1988 and may 1988)
NRC regulation 10 CFR Part 50.49, which went into effect on March 31, 1985, attempts to ensure that safety equipment exposed to harsh environments during an accident will con- tinue to function under such conditions. When the NRC notified TVA that its Sequoyah plant was going to receive one of the first audits the agency was planning to conduct under these new requirements, TVA hired an independent company to pre-audit Sequoyah.
The pre-audit results were so bad that TVA voluntarily shut down both Sequoyah reactors to correct the problems. The NRC then resisted concerted efforts by the company to confine its corrective measures to equipment qualification problems, and also forced TVA to address pro- grammatic problems at Sequoyah that had plagued the company’s reactors at Browns Ferry in Alabama and Watts Bar in Tennessee as well.
TVA then tried to get away with the ethi- cal equivalent of turning in a test with grades the company had already assigned to itself. The NRC balked, asking TVA to bring in another independent company to determine whether TVA’s restoration efforts had been thorough and effective. When the company refused, the NRC sent its own team of inspectors, which docu- mented more than five dozen problems in just a single system. TVA had to go back and do much more work.
tUrkey POint Unit 3 (flOrida City, fl, febrUary 1981 tO aPril 1982)
For nearly four years prior to this outage, the NRC maintained a dynamic yet effective bal- ance between protecting public health from an unexpected hazard and allowing another reactor to operate in a time of uncertainty. The unex- pected hazard was the steam generator tube leak
Walking a Nuclear Tightrope
that occurred at Virginia’s Surry nuclear power plant in September 1976. Though the NRC had anticipated such leaks when licensing reactors like Surry and Turkey Point, it had not antici- pated the rapid rate of corrosion that caused the Surry tube to leak.
To avoid unfairly burdening Turkey Point’s owner for the problem that had occurred at Surry (while also protecting the public by studying this problem’s true dimensions), the NRC allowed Turkey Point to operate for up to six months between the shutdowns needed to inspect the plant’s steam generator tubes. The agency also adjusted the operating period between inspections as more data became available from Turkey Point and other plants. By the time Florida Power & Light shut down Turkey Point Unit 3 in February 1981 to replace the steam generators entirely, the NRC had accumulated sufficient information about the corrosion problem to know that the replacement equipment would be more resistant to corrosion—justifying longer intervals between inspections.
Finishing a close fourth was the agency’s performance during the outage at Surry Unit 2 from September 1988 to September 1989. The NRC reacted to an emerging problem (pipe wall thinning) in a thorough and timely manner both at Surry and at other affected reactors around the country.
The agency also deserves honorable men- tion for its performance during the outages at Michigan’s Donald C. Cook Units 1 and 2 that began in September 1997. The NRC design inspection team found serious, but subtle, design problems that had gone unnoticed by previous inspectors for up to 20 years.
Signs of Slippage?
It was disconcerting to realize that all three of the NRC’s best performances occurred nearly two decades ago, while two of the “Terrible Three”