TRANSMITTED TO DOE/M. WHITAKER 04/19/95

DEFENSE NUCLEAR FACILITIES SAFETY BOARD

                                             April 8, 1994

MEMORANDUM FOR:       G. W. Cunningham, Technical Director

COPIES:               Board Members

FROM:                 Ajit Gwal

SUBJECT:              Report of Trip to Old HB-Line - Rooms 302, 304 &
                      306


1.  Purpose:  This memorandum reports the observations of DNFSB staff member
    Ajit Gwal during a visit to the Savannah River Site on March 17, 1994, to
    review the ventilation and fire protection systems in Rooms 302, 304 and 306
    of the Old HB-Line.

2.  Summary:  The following major issues and observations were identified:

    a.  An air flow reversal event, similar to the airborne contamination event
        that occurred in October 1993, will occur upon loss of normal power and
        the 292-H diesel.

    b.  Room 304 contains a sufficient amount of combustible materials to
        create a severe fire hazard.  The room contains no fire detection
        devices.  Also, if a fire in room 304 is sufficiently intense, there
        is the possibility of its propagating to the adjacent room 302, with
        possible melting of the 16 gauge ventilation duct, and resulting in an
        air flow reversal and airborne contamination.

    c.  Radiological Controlled Area (RCA) signs, stating that airborne
        contamination exists beyond the doors, are posted on the two doors of
        room 304 which open to the west corridor.  Both doors have open holes
        and long cracks.  During loss of ventilation, air flow reversal could
        occur, and airborne contamination could expose the workers.

3.  Background:  Mr. Dan Burnfield of the DNFSB staff had previously reviewed
    radiological work practices in rooms 302, 304, and 306 of the old HB-Line
    and requested the review of the fire protection and ventilation system
    reported herein.

4.  Discussion/Observations:  DNFSB staff observations and findings from this
    review are as follows:

    a.  Ventilation and power outage scenario:  

            Loss of normal power and 254-5H#1 diesel (see Attachment 1). 
            Loss of normal power and 254-5H#2 diesel (see Attachment 2).
            Loss of normal power and 221-H diesel (see Attachment 3).
            Loss of normal power and 292-H diesel (see Attachment 4).
            221-H ventilation system normal operation (see Attachment 5).

        The electrical feed configurations of supply and exhaust fans for these
        scenarios are presented schematically in Attachments 1 through 4. 
        Attachment 5 provides the configuration for the normal operation of the
        ventilation system.  Air reversal will not occur in scenarios 1 through
        3.  However, scenario 4 will lead to air flow reversal in room 306. 
        It is anticipated that the Department of Energy (DOE) will evaluate
        this scenario and provide timely corrective action.

    b.  Fire protection:  There are no fire detection devices in room 304,
        which contains sufficient combustible materials to create a severe fire
        hazard.  Room 304 is not continuously occupied.  The staff believes it
        would be prudent to have a fire detection system with an alarm in the
        control room and to start roving fire watches at suitable intervals of
        time, to detect and suppress any fire.

        A severe fire in room 304 has the possibility of propagating through
        a drywall to the adjacent room 302, which contains the exhaust
        ventilation duct for room 306 (Attachment 6).  Under such conditions
        there is a possibility that the 16-gauge exhaust duct material in room
        306 could melt during a fire and this could result in an air reversal
        and airborne contamination.

    c.  Airborne contamination:  RCA signs are posted on the two doors of room
        304, which opens in the west corridor.  The sign states that airborne
        contamination exists beyond the doors.  It was noted, however, that
        these doors have open holes and long cracks.  During normal operation,
        air flows from room 304 to the west corridor, ordinarily this does not
        pose any safety concerns for the workers present in room 304.  However,
        during loss of ventilation, air flow reversal could occur and airborne
        contamination could expose the workers.

5.  Future Staff Actions:  The DNFSB staff intends to conduct follow-up reviews
    of the technical concerns identified in this memo to determine what actions
    are taken by DOE to:

    a.  Evaluate and implement the corrective action to prevent any air flow
        reversal in room 306 due to loss of normal power and 292-H diesel.

    b.  Evaluate and implement the corrective action to install a fire
        detection system and to start fire watches.

    c.  Evaluate and implement the corrective action to prevent the exposure
        of workers to the airborne contamination due to existing holes and
        cracks in the doors of room 306.