[US
LETTERHEAD]
October 13, 2004
The Honorable John T. Conway
Chairman
Defense Nuclear Facilities
Safety Board
625 Indiana Avenue, NW, Suite
700
Washington, DC 20004-2901
Dear Mr. Chairman:
This is in response to your
letter to me dated August 27, 2004, concerning the adequacy of Department of
Energy (DOE) natural phenomena hazards design standards and the performance
category (PC) designation for the conceptual seismic design of the Savannah
River Site (SRS) Salt Waste Processing Facility (SWPF). As part
of our nuclear safety management implementation, the Department places a high
priority on hazards evaluation and mitigation, and on the protection of our
workers and the public. The Department
therefore carefully reviewed your letter and extensively considered the issues
it raised, including whether further guidance in DOE Directives is required.
Based on your letter, we
reviewed the background and intent of the guidance in DOE Guide 420.1-2, Guide for the Mitigation
of Natural Phenomena Hazards for DOE Nuclear Facilities and Non-nuclear
Facilities, and DOE Standard 1021-93, Natural Phenomena Hazards
Performance Categorization Guidelines for Structures, Systems and Components,
regarding the
consideration of PC-3 designation of structures, systems and components (SSC’s)
for worker safety. Consideration of PC-3
designation for worker protection relies on judgment by line management
considering several factors, including the results of safety analyses.
Our review concluded that DOE
guidance can be strengthened by providing clarification and supplemental
guidance on factors that should be considered in determining whether PC-3 SSC’s
are appropriate for worker protection. Accordingly,
we will revise the guidance documents noted above and any other affected DOE
Directives or guidance documents by January 31, 2005. These revisions will deal with such issues as
local confinement, protection of in-facility workers and co-located workers,
design margins, and consideration of the ensemble of safety controls and the
results of safety analyses for events of concern. Your staff will be consulted on the revision
of those guidance documents.
We also considered your
suggestion that the confinement features of SWPF may be more appropriate
designed as PC-3, rather than the current PC-2 designation. The enhanced conceptual design for the SWPF
was recently completed and the preliminary hazards analysis (PHA) is being
revised at this time to reflect the most recent design changes and process
enhancements, to incorporate additional information on waste feed
characteristics based on sampling of bounding waste tanks, and to incorporate
additional controls and defense in-depth to enhance safety. Review of the revised PHA by the Department’s
Savannah River Operations Office identified additional areas for improvement
that enhance the conceptual design.
The basis established in the
revised PHA for functional classification and performance categorization of key
confinement SSC’s for the SWPF has been the subject of continuing staff to
staff discussions. The latest detailed
discussion was held on September 29, 2004. As facility
design and safety basis development progresses, we will continue to work with
the Board’s staff to assure that worker and public safety are protected. To ensure that information is sufficient for
both the Board and DOE safety reviews, we will provide a briefing to you and
your staff within 60 days.
I
have asked Mr. Dae
Chung of the Office of Environmental Management to coordinate this briefing
with your staff. If you have any
additional questions regarding our plans for updating DOE guidance on natural
phenomena hazards or the SWPF project, please feel free to contact me.
Sincerely,
David K. Garman
cc:
J. Shaw, EH-1
M. Whitaker, DR-1
P. Paul Golan, EM-1
D. Chung, EM -24
J. Allison. SRS