**\[DNFSB LETTERHEAD\]**

September 7, 2005

Mr. James A. Rispoli

Assistant Secretary for

Environmental Management

U.S. Department of Energy

1000 Independence Avenue, SW

Washington, DC 20585-0113

Dear Mr. Rispoli:

The Defense Nuclear Facilities Safety Board (Board) is aware that the
Office of River Protection (ORP) has embarked on the design and
construction of a pilot plant at the Hanford Site to demonstrate bulk
vitrification of low-activity waste, a method that may be used to
supplement the Waste Treatment Plant. The Board understands the limited
operational life of this pilot plant and its potential benefits.
However, the Board is also interested in ensuring that this facility is
built with appropriate features to prevent escape of radioactive
materials and to protect the workers.

The enclosed report presents observations of the Board's staff resulting
from a review of the Demonstration Bulk Vitrification Project and is
provided for your information and use as appropriate. The report notes
potential weaknesses in such areas as the confinement of materials and
worker protection that need to be considered in finalizing the design of
the facility. The Board is aware of and is encouraged by the fact that
ORP and its contractor have already taken steps to evaluate some of the
issues raised in this report.

Therefore, pursuant to 42 U.S.C. § 2286b(d), the Board requests, at a
time consistent with the maturity of the design for the Demonstration
Bulk Vitrification Project, a briefing on the resolution of the issues
identified in the enclosed report. The Board expects this briefing to
occur no later than January 2006. In addition, the Board requests,
within 60 days of receipt of this letter, a briefing on ORP's technical
and programmatic oversight of this project.

Sincerely,

***A. J. Eggenberger***

***Chairman***

c: Mr. Mark B. Whitaker, Jr.

Mr. Roy J. Schepens

Enclosure

**DEFENSE NUCLEAR FACILITIES SAFETY BOARD**

**Staff Issue Report**

August 9, 2005

**MEMORANDUM FOR:** J. K. Fortenberry, Technical Director

**COPIES:** Board Members

**FROM:** J. W. Troan

**SUBJECT:** Demonstration Bulk Vitrification Project, Hanford Tank
Farms

The purpose of this report is to document reviews of the Demonstration
Bulk Vitrification Project conducted by the staff of the Defense Nuclear
Facilities Safety Board (Board); these reviews included site visits
during May 2426 and July 1214, 2005. Members of the Board's staff M.
Feldman, A. Matteucci, J. Shackelford, J. Troan, and R. Zavadoski
participated in the reviews. The staff met with personnel from the
Department of Energy (DOE) Office of River Protection (ORP), CH2M Hill
Hanford Group, Inc. (CHG), and the demonstration bulk vitrification
system subcontractor, AMEC, to discuss the design, preliminary safety
analyses, and controls for the project.

**Background.** The project consists of a full-scale facility for
research, development, and demonstration of the bulk vitrification
process. The facility will be used to vitrify waste from single-shell
tank S-109 to demonstrate the effectiveness of the process as means of
supplementing the low-activity waste capacity of the Waste Treatment
Plant (WTP).

Supplementing the WTP is considered necessary to meet the milestones of
the Tri-Party Agreement for completing retrieval of waste from Hanford
single-shell tanks by 2018 and treatment of tank waste by 2028.

The design and construction of the demonstration bulk vitrification
facility are expected to be completed by early 2006. The first campaign
using radioactive waste is expected to start in mid-2006. In December
2004, the Washington State Department of Ecology issued a permit to ORP
and CHG to operate the demonstration bulk vitrification facility. The
permit remains in effect for a maximum of 400 "operating" days or 3
years, whichever comes first. Closure activities will follow operations,
and the facility is then expected to be decontaminated and
decommissioned.

Several aspects of the facility design, operation, and testing are not
fully developed.

Many elements of the design are new and unproven and will require
testing. Because of the status of the project, many issues and questions
identified by the Board's staff remain unresolved, and much work must be
completed before operations begin. The following observations highlight
some issues noted by the staff.

**Design.** The current design has a number of major vulnerabilities
with respect to overall confinement of radioactive and hazardous
materials. Contrary to DOE's design requirements to use successive
physical barriers for protection against the release of
radioactivity,[^1] the current design uses only one barrier to confine
material in portions of the plant. The project's confinement strategy
also relies on a mix of active and passive safety-significant systems,
non-safety-related design features, and administrative controls.

Safety-significant confinement boundaries include double-walled
(hose-in-hose transfer line) piping, double-walled tanks, and piping
designed to the requirements of American Society of Mechanical Engineers
B31.3, *Process Piping*. Non-safety-related design features include the
In-Container Vitrification^TM^ container, which includes connections to
the off-gas treatment system and dried waste transfer system. Because
these design features are not classified as safety-significant, they may
lack reliability and availability commensurate with their safety
functions.

The confinement strategy also relies on the implementation of a specific
administrative control to ensure the closure of three non-safety-related
cone valves (from the clean soil impingement tanks). These three valves
are collocated with the safety-significant dryer outlet cone valves on
top of the vitrification container and form a portion of the overall
confinement boundary.

As a result of these vulnerabilities, the potential exists for the
failure of a single non-

safety-related barrier that could lead to the unfiltered release of
radioactive or toxic materials and unacceptable consequences to workers.
For example, failure of the integrity of the non-safety related
vitrification container could result in an unfiltered and untreated
release of radioactive and toxic material.

Guidance and requirements establish that structures, systems, and
components serving a safety-significant confinement function be
classified as safety-significant, that successive physical barriers be
used to protect against the release of radioactivity, and that the
number and arrangement of confinement barriers and their required
characteristics be determined on a case-by-case basis. This approach
leads to a minimum of two physical barriers for the protection against
the release of radioactivity, with at least one barrier designated as
safety-significant. The Board's staff observed that in some portions of
the demonstration bulk vitrification facility the confinement barrier is
not designated safety-significant and successive physical barriers are
not used. The justification for the demonstration bulk vitrification
facility's confinement strategy is not adequate. The staff needs
additional information to better understand the reason for not
designating some physical barriers as safety-significant and not using
successive physical barriers. This justification ought to include more
complete hazard assessments, engineering evaluations, alternatives that
were considered, and compensatory measures.

Since the facility's design predates the Board's Recommendation 2004-2,
*Active Confinement Systems*, the overall confinement strategy does not
incorporate considerations set forth therein regarding an active
confinement system. As a result, the proposed design does not align well
with the expectations and guidance being developed in the Implementation
Plan for Recommendation 2004-2.

**Safety Analyses.** The staff observed weaknesses in the analysis of
anticipated events and in source term assumptions. As noted earlier,
since the design is not complete, many issues and questions identified
by the staff remain unresolved.

For example, an anticipated system upset condition, such as the loss of
power during vitrification, was initially viewed by the contractor as an
abnormal event that would result in a focused decision at the time of
occurrence as to whether to recover by restarting the melt. The Board's
staff believes that, given the expected nature of this occurrence,
further analysis of the restarting of the process and the hazardous
conditions that could result is warranted. Confirming the behavior of
the postulated upset and the recovery procedures for this and other
abnormal operating scenarios may be appropriate as part of the project's
test program prior to the introduction of radioactive material.

Experience has shown that certain fission products from vitrified waste
will volatalize, migrate, and collect in various portions of the off-gas
treatment system. The possibility of undesirable accumulation of
radioactive materials in this system has not been adequately considered
in the current design. As a result, some of the hazards associated with
operations, upsets, and maintenance may not be appropriately
anticipated. As part of the project's test program, it may be advisable
to evaluate actual performance characteristics relative to the carryover
and hold-up of fission products in the off-gas treatment system.

**Safety of Facility Workers.** The contractor's approach to identifying
safety-significant controls to protect facility workers does not appear
to be consistent with the expectations contained in DOE directives. ORP
and the contractor have drawn a distinction between facility workers and
collocated workers such that in general, scenarios with significant
consequences to collocated workers have safety-significant controls,
while scenarios with significant consequences only to facility workers
rely on safety management programs. In the Preliminary Documented Safety
Analysis, no safety-related structures, systems, and components are
identified as exclusively protecting the facility workers. However,
several non-safety-related engineered features are included in the
demonstration bulk vitrification system design to reduce the hazards to
these workers (e.g., shield walls, enclosures, ammonia sensor/alarm).
While hazards to facility workers are typically addressed through safety
management programs, the Board's staff believes it would be advisable to
consider the use of safety-significant controls to address exposure of
facility workers to significant radiological and chemical hazards.

For example, ammonia is identified in the Preliminary Documented Safety
Analysis as a hazardous material that is stored and used at the
demonstration bulk vitrification facility.

Approximately 9,000 lb of ammonia will be delivered and stored in a tank
for use in the off-gas treatment system. The Preliminary Document Safety
Analysis states that nonradiological hazards, such as chemical hazards,
are addressed by safety management programs (e.g., industrial safety and
industrial hygiene programs), and lists non-safety-related engineered
features that mitigate the ammonia hazard (e.g., vehicle barriers,
sensor and alarm, and a standard for building and testing the pressure
vessel). The Board's staff is concerned that ammonia poses a significant
hazard to workers, and that the ammonia hazard is not being
appropriately recognized and controlled. The staff believes it would be
advisable to protect workers from this hazard through safety-significant
structures, systems, and components and Technical Safety Requirements,
such as Limiting Conditions of Operation and Specific Administrative
Controls.

[^1]: In accordance with DOE Order 420.1A, *Facility Safety*.