[DNFSB
LETTERHEAD]
April 20, 2005
The Honorable Everet H. Beckner
Deputy Administrator for Defense
Programs
National Nuclear Security
Administration
U.S. Department of Energy
1000 Independence Avenue, SW
Washington, DC 20585-0104
Dear Dr. Beckner:
The staff of the Defense Nuclear
Facilities Safety Board (Board) recently conducted a review of the structural
deficiencies of Building 9212 at the Y-12 National Security Complex. These deficiencies are noted in safety basis
documentation submitted to the National Nuclear Security Administration (NNSA)
for review and approval. Results of
analyses of the building’s structure indicate that it would not withstand
performance category-2 seismic loads and that many of the building’s systems
and components have insufficient seismic restraint. The enclosed report prepared by the Board’s
staff summarizes observations noted during this review.
The Y-12 contractor, BWXT,
recommended to NNSA that modifications addressing the structural deficiencies
of Building 9212 not be made because of the facility’s limited life, given the
planned construction and startup of a replacement facility by 2013. The Board recognizes the need for a new facility―the
Uranium Processing Facility (UPF)―for enriched uranium operations that
would significantly improve safety and security at Y-12. The Board also believes, as indicated by Y-12
management, that NNSA should work aggressively to eliminate the backlog of
nuclear materials (especially solutions) that have accumulated in Building 9212
during many years of operations. At the
same time, however, there are opportunities to implement near-term structural
improvements or other facility modifications that would reduce the structural
vulnerabilities associated with the building.
The Board recognizes that NNSA
is evaluating the contractor’s proposal and has not determined a path forward. The Board believes that an appropriately
balanced plan encompassing construction of a new facility, reduction of
material at risk, and implementation of practical facility modifications is
prudent and necessary for Building 9212. Therefore, pursuant to 42 U.S.C. § 2286b(d),
the Board requests a briefing on NNSA’s path forward regarding the structural
deficiencies of Building 9212 within 30 days of NNSA’s taking action on the
proposed safety basis, including plans to eliminate the backlog of nuclear
materials. The Board also requests a
discussion of the impact on these plans if UPF is delayed, including the point
at which more aggressive remedies with respect to Building 9212 would be
required.
Sincerely,
A. J. Eggenberger
Acting Chairman
c: Mr. William J. Brumley
Mr.
Mark B. Whitaker, Jr.
Enclosure
DEFENSE
NUCLEAR FACILITIES SAFETY BOARD
Staff
Issue Report
April
11, 2005
MEMORANDUM FOR: J.
K. Fortenberry, Technical Director
FROM: W. Linzau
SUBJECT: Structural Deficiencies,
Building 9212
This report documents a review
by the staff of the Defense Nuclear Facilities Safety Board (Board) regarding
structural deficiencies of Building 9212 at the Y-12 National Security Complex
(Y-12). To conduct this review, staff
members W. Linzau, M. Moury, D. Owen, and T. Davis participated in discussions
with site personnel and a walkdown of the facility on March 3, 2005. This report was supplemented by follow-up phone
calls with contractor during the week of March 20, 2005 and April 11, 2005.
Background. Building 9212 was constructed in stages during the 1940s and
1950s. Its primary mission is to recover
and process enriched uranium for defense missions, as well as to store various
forms of enriched uranium. The
contractor, BWXT, submitted a new Documented Safety Analysis (DSA) for Building
9212 to the National Nuclear Security Administration’s Y-12 Site Office (YSO)
for approval. YSO is currently
evaluating the DSA and plans to issue a Safety Evaluation Report by June 2005.
In December 2004, approval of
Mission Need (Critical Decision-0) was received for the new Uranium Processing
Facility (UPF). This facility will
assume the primary mission functions of Building 9212, allowing the latter
facility to be deinventoried and deactivated. Startup of UPF is projected for 2013. Uncertainties in the timing and level of
funding could negatively impact the proposed schedule.
Structural
Deficiencies.
To support the DSA, BWXT completed an analysis of the building’s
structural response to natural phenomena events. The results show that portions of the facility
would fail during a performance category (PC)-2 seismic event,
and the roof would be damaged by a PC-2 wind event. The structural deficiencies include numerous
failures of the bracing providing lateral force resistance, with failures
typically occurring at the connections that are bolted or riveted. Other bracing has been cut or removed in the
past. Moreover, sections of the facility
were constructed without an adequate lateral load path, thus allowing excessive
deformation of beams and columns during a PC-2 seismic event.
BWXT also performed an
evaluation of the seismic resistance capacity of components and systems within
the facility. The results show that
seismic resistance was not considered in the design of most of the supports and
anchorages of various tanks, glass columns, storage racks, throughout the
facility.
BWXT prepared order-of-magnitude
cost and schedule estimates for bringing the facility into PC-2 compliance. Addressing all the deficiencies is estimated
to cost $35-72 million and to take more than 60 months. The cost to fix only equipment, such as the
glass columns, racks, and tanks, is estimated to be $29-57 million.
Given the cost and schedule
estimates for full PC-2 compliance and the expected remaining life of the
facility, BWXT has concluded that it would not be cost-beneficial to make the
necessary structural improvements. Additionally, BWXT has concluded that low-cost
modifications would not significantly reduce the overall consequences of a
seismic event. BWXT believes resources
should be focused on the reduction of material at risk in Building 9212 and on
the design and construction of UPF.
Observations. BWXT has not supplied YSO with detailed options for
structural improvements or other modifications, including refined cost
estimates and analyses of the safety benefits and risk prioritization of such
options. In addition, simple,
straightforward upgrades appear practical, such as adding support for at-risk
beams and replacing understrength bolts and braces
with higher-capacity members. During a
walkdown of Building 9212, the staff noted numerous loose or missing nuts and
bolts for equipment supports that compound the structure’s weak seismic
resistance. Tightening existing
equipment supports would help ensure that their limited capacity is maximized. Such improvements ought to be prioritized
considering the material at risk, impacts to operations, and available
resources. A systematic evaluation of improvement
options would allow YSO to make an informed decision on the proper path forward
regarding the structural deficiencies of Building 9212.
An example of a hazard that
might be addressed by a low-cost modification is the potential for rupture and
ignition of flammable gas lines during a seismic event. To prevent large postearthquake
fires, automatic seismic isolation valves are often used for such supply lines.
Building 9212 uses this type of valve
for the hydrogen fluoride supply line because of the toxicological hazard, but
does not use such valves for the natural gas lines that supply the building.
Additional
Information.
During the walkdown of Building 9212, the staff noted that one
of the structural members in an adjacent support building―the Stack
110 Bag House―was
missing. The missing member is a
first-floor structural brace that appears to be essential in providing lateral
support for the structure. The required
work packages were completed and the missing brace was replaced April 7, 2005. YSO is working with BWXT to understand the broader
safety implications of the loss of configuration management indicated by the identification
of a missing structural brace.