November 6, 1995


The Honorable Thomas P. Grumbly
Assistant Secretary for Environmental Management
Department of Energy
Washington, D.C.  20585-0113

Dear Mr. Grumbly:

Members of the Defense Nuclear Facilities Safety Board's (Board)
staff recently reviewed both the electrical and structural design
and construction of the Defense Waste Processing Facility (DWPF)
at the Savannah River Site.  The Board's staff noted findings in
each area.  The enclosed report on the electrical review is
provided for your information.

The Board believes the following two issues should be resolved
prior to facility startup.  As currently designed, several
electrical loads are sequenced to the emergency diesel generators
(EDG) using the DWPF's Distributed Control System (DCS).  DCS is
not a  safety-related system and could fail during certain
accident scenarios.  This failure could potentially render the
EDGs unavailable to supply safety loads, such as the Zone 1
Ventilation System.  The second issue involves the separation
between the safety and nonsafety electrical busses.  As noted,
certain nonsafety loads, such as the melter, can be operated
during a normal loss of offsite power.  However, only one
safety-related circuit breaker exists between the busses to
provide isolation.  This violates single failure criteria and
could lead to the loss of emergency backup power.

The Board's staff also noted that cable tray supports in the
Emergency Control Center have questionable seismic integrity. 
Their failure could lead to damage of the control panels.  The
Board understands that the completion of seismic qualifications
for safety-class equipment, including Seismic II/I walkdowns and
evaluations, will be completed prior to facility startup.

DWPF startup is currently scheduled for December 30, 1995.  The
Board believes that adequate resolution of the issues noted in
this letter should not delay startup.  

Please contact Mr. Joseph Sanders of my staff if you need any
additional information or assistance.

                                    Sincerely,



                                    John T. Conway
                                    Chairman

c: Mr. Mark Whitaker
   Dr. Mario Fiori

Enclosure


DEFENSE NUCLEAR FACILITIES SAFETY BOARD
                                              October 13, 1995

MEMORANDUM FOR: G. W. Cunningham, Technical Director

COPIES:         Board Members

FROM:           Ajit K. Gwal

SUBJECT:        Trip Report on Savannah River Site (SRS)
                Defense  Waste Processing Facility (DWPF) 
                Electrical Systems

1.  Purpose:  This report documents a review of the electrical
systems at the Savannah River Site (SRS) Defense Waste
Processing Facility (DWPF) by the Defense Nuclear Facilities
Safety Board's (Board) staff members, Ajit Gwal and William
White, on September 27-29, 1995.

2.  Summary:  The safety-class diesel generators at DWPF
currently support both safety- and nonsafety-class electrical
loads. Nonsafety loads are sequenced to the diesel generators by
a distributed control system (DCS), which is not a safety-class
system.  If the DCS malfunctions during loss of power and
fails to sequence the loads properly, the diesel generators might
not be available to supply power to safety-class loads, such as
the Zone 1 exhaust fans and certain radiation monitors.    In
addition, there is only one safety-class breaker separating
the safety bus from the nonsafety bus.  The use of a single
breaker to provide separation between safety and nonsafety busses
does not meet the requirements of Institute of Electrical and
Electronics Engineers (IEEE) 384 (Separation Criteria) and
IEEE 379 (Single Failure Criterion).

Emergency lighting at DWPF is not seismically supported and thus
might not be available after a seismic event.  Also,
Westinghouse Savannah River Company (WSRC) was unable to confirm
that the battery rooms in the DWPF vitrification building comply
with the American National Standards Institute (ANSI) C2 National
Electric  Code.

3.  Background:  WSRC has recently designated a few select
electrical, instrumentation, and control systems at DWPF as
safety class.  This is the first review of these electrical
systems since their upgrade to safety-class systems.  DWPF is
currently in startup testing with expected readiness for
radioactive operations by the end of 1995. 

4.  Discussion/Observations:  

 a. The review identified the following potentially significant
    issues at DWPF:

    1. Nonsafety Loads on the Emergency Diesel Generators: 
       During its review of one-line diagrams for the new
       operating configuration of the safety-class electrical
       system at DWPF, the Board's staff observed that there are
       nonsafety loads, such as Building 292-S HVAC and the
       health physics vacuum blowers, connected to safety-class
       electrical busses without appropriate isolation devices. 
       In addition, other nonsafety loads, such as the melter,
       are supplied by a nonsafety bus that can be connected to
       the safety bus powered by the emergency diesel generators. 
       In this configuration, there are no electrical isolation
       devices as required by ANSI/IEEE standard 384, Standard
       Criteria for Independence of Class 1E Equipment and
       Circuits, and ANSI/IEEE standard 379, Standard Application
       of the Single Failure Criterion to Nuclear Power
       Generating Station Safety Systems. There is only one
       safety-class circuit breaker separating the safety-class
       electrical bus from the nonsafety bus, instead of the
       required two safety-class breakers in series.  The Board's
       staff is concerned that a single fault on the nonsafety
       bus could render the safety-class power supply inoperable.

       Sequencing for the nonsafety loads is currently done by
       the nonsafety DCS.  If the DCS malfunctions during loss of
       power and fails to sequence the loads properly, the diesel
       generators might not be able to supply power to            
       safety-class loads, such as the Zone 1 exhaust fans and    
       certain radiation monitors.  WSRC plans to conduct         
       simulations before startup to demonstrate that the         
       nonsafety loads (which consume roughly 10 percent of       
       diesel capacity) could not cause diesel failure through    
       improper sequencing.  

       On the other hand, if only safety-class loads are powered
       by the generators, operators will lose instrumentation and
       control, which are nonsafety class, during a loss of power
       event.  Loss of power has been a frequent (twice yearly)
       occurrence at DWPF.  If the loss of power continues long
       enough, the melter could freeze and become inoperable. 
       WSRC officials estimate it could cost up to $40 million to
       replace a frozen melter.  WSRC intends to resolve the
       above issues.

    2. Emergency Lighting:  The emergency lighting at DWPF is
       not seismically supported.  These lights, which
       illuminate personnel egress routes during an
       electrical loss of power, might not be available after
       a seismic event.  WSRC personnel are reviewing this
       situation and will provide the Board's staff with
       their resolution.

    3. Battery Ventilation:  ANSI C2 National Electric Safety
       Code requires adequate ventilation and loss of ventilation
       alarms for rooms with lead-acid batteries to ensure
       hydrogen does not build up and result in an explosion. 
       The battery rooms in the vitrification building have
       recently been redesigned, but WSRC personnel were unable
       to confirm that the new design meets ANSI C2.

    4. Ampacity Derating of Fire-Protected Cables:  WSRC uses
       fire-protected cables in DWPF building 292-S to ensure
       continued cable performance during a fire exposure.        
       Fire-protection related products, such as those used at    
       DWPF, may reduce the heat transfer characteristics        
       associated with the cable ampacity.  The Board's staff     
       observed that WSRC has not determined the ampacity        
       derating of the fire-protected cable systems at DWPF to    
       confirm cable performance during a fire exposure.  WSRC    
       will provide the Board's staff with relevant        
       documentation.  The Board's staff is concerned that the    
       cable may not perform its intended function.

    5. Electrical Calculations: Electrical calculations for
       voltage profile, short circuit studies, and protective
       device coordination, as required by ANSI/IEEE Standard 141
       IEEE Recommended Practice for Electrical Power
       Distribution for Industrial Plants and ANSI/IEEE Standard
       242 IEEE Recommended Practice for Protection and
       Coordination of Industrial and Commercial Power Systems,
       are incomplete.  Without these calculations, WSRC cannot
       verify the capability of electrical equipment to withstand
       potential short circuits.  WSRC plans to complete the
       calculations before beginning radioactive operations, and
       the Board's staff will review the completed calculations
       when they are available.

    6. Environmental Qualification:  Safety-class electrical
       equipment at DWPF is not qualified per IEEE Standard 323
       Qualifying Class 1E Equipment for Nuclear Power Generating
       Stations.  WSRC is currently writing a justification for
       not qualifying this equipment.  The staff will review the
       justification when it is available.

    7. Distributed Control System/Alarm Management:  In an effort
       to improve human factors in the DWPF control room, WSRC is
       procuring and installing an alarm management system that
       will filter the alarms received in the control room.  This
       system will determine which alarms are important and will
       also diagnose probable causes of alarms.  This might work
       out very well if the expert systems are accurate. 
       However, if the expert systems do not perform as
       advertised, the operators could be relying on inaccurate
       information during emergency situations.  The Board's
       staff will continue to review this issue.

    8. Fire Protection of the Central Control Room (CCR):  In a
       trip report dated December 1, 1993, the Board's staff
       expressed concern over WSRC's plans to provide a water
       sprinkler system in lieu of a Halon system in the CCR. 
       With a water sprinkler system, water intrusion into
       electrical panels could result in electrical shorts,
       spurious operations, and make it difficult to control the
       plant from remote control panels.  WSRC has reevaluated
       its earlier decision and now plans to use a Halon system
       in the CCR.  While this approach is technically
       acceptable, the Board's staff expressed concerns over the
       future availability of Halon, which is no longer being
       produced in the United States. The Department of Energy
       (DOE) and WSRC have completed a study on the future
       availability of Halon at DWPF.  This study will be
       supplied to the Board's staff for its review.

 b. The review also identified two systems at DWPF that are
    significant improvements over similar systems at SRS and
    other DOE nuclear facilities.

    1.    Electrical Characteristics and Diagnostic System:  The
          Board's staff was impressed with the Electrical
          Characteristics and Diagnostic System 1000 data
          acquisition system.  This automated system is an
          informative technology program that covers electrical
          system inspection, trouble shooting, condition
          monitoring, and preventive maintenance.  DWPF has used
          this system to obtain baseline information for almost
          all of the critical electrical systems in the
          facility.  This information, if properly used, will
          allow DWPF to easily locate and diagnose electrical
          failures and to plan for plant life extension.

    2. Lightning Protection System:  The lightning protection
       system at DWPF was designed in accordance with DOE Order
       6430.1A, Section 1630.5 and National Fire Protection
       Association 780, Lightning Protection Code.  In addition
       to this system, DWPF has a lightning dissipation array
       system for equipment and control system protection.  Since
       the system was installed in 1992, there have been no
       direct lightning strikes at DWPF. 
 
5.  Future Staff Actions:  The Board's staff will follow the
resolution of concerns regarding the assignment of nonsafety
loads to safety-class electrical buses.  The staff also plans
to review the new facility electrical calculations and the   
justifications for not qualifying safety-class equipment per
IEEE 323.  The staff will perform another review at DWPF to look
more closely at the distributed control system and alarm
management and to review compliance of battery room ventilation
and loss of ventilation alarms with ANSI C2.