Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555
June 1, 1992
NRC INFORMATION NOTICE 92-42: FRAUDULENT BOLTS IN SEISMICALLY DESIGNED
WALLS
Addressees
All holders of operating licenses or construction permits for nuclear
power reactors.
Purpose
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information
notice to alert addressees to fraudulent anchor and through wall bolts
found in seismic structures. It is expected that recipients will review
the information for applicability to their facilities and consider
actions, as appropriate, to avoid similar problems. However, suggestions
contained in this information notice are not NRC requirements; therefore,
no specific action or written response is required.
Description of Circumstances
From March 30 through April 10, 1992, an NRC engineering team performed
a special inspection at the Brunswick Steam Electric Plant. The
inspection included masonry block and poured concrete walls in the
building housing the diesel generators that provide emergency electrical
power for the plant. The team discovered that many of the bolts in these
walls which appeared to exist and provide lateral support, did not in fact
exist. The bolts were apparently installed during plant construction by
a subcontractor to Brown and Root. In many instances, heads cut from
bolts had been attached to the angle iron that was designed to provide
lateral support for the walls during an earthquake. The bolt heads made
it appear that there were bolts supporting the wall, but without the bolt
shanks there was no support. In the worst case, more than 85 percent of
the bolts installed in one wall were either fraudulent or did not
otherwise meet design requirements. For some of these bolts, the anchors
had not been installed. In other cases, the bolts were too short to ade-
quately engage the anchors. Other bolts that should have completely pene-
trated the walls did not.
Some employees of Carolina Power and Light Company, licensee for the
Brunswick plant, were aware of problems with bolts in some walls in 1987.
Nevertheless, the licensee did not take effective action to determine the
extent of the problem and correct it. Initially, the licensee used feeler
gauges inserted under the angle iron to determine whether or not the
shanks of bolts were in place. In some cases, because the licensee's
inspector could feel the anchor sleeve, the licensee assumed that bolt
shanks were present when they were not. However, during and after NRC's
special inspection, the licensee performed
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inspections and evaluations that were progressively more thorough. On the
basis of that work, the licensee concluded that certain of the walls were
not capable of performing their intended safety function and the licensee
has shut down both reactors until the problem is corrected.
Discussion
The block and poured concrete walls separate the four trains of emergency
diesel generating equipment and ensure that all of the trains do not
become inoperable because of a common hazard. The masonry block walls and
the steel plates attached to them provide missile protection for this
equipment. The walls were intended to withstand the design-basis
earthquake. The capability of the walls to perform their intended
function has been compromised since the fraudulent and deficient bolts
were installed in approximately 1973.
This information notice requires no specific action or written response.
If you have any question about the information in this notice, please
contact one of the technical contacts listed below or the appropriate
Office of Nuclear Reactor Regulation (NRR) project manager.
Charles E. Rossi, Director
Division of Operational Events Assessment
Office of Nuclear Reactor Regulation
Technical contacts: John Thompson, AEOD
(301) 492-8091
Roger Woodruff, NRR
(301) 504-1152
Attachment: List of Recently Issued Information Notices
