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| DOE-STD-1058-93
Fire in the Cable Spreading Room
The refueling floor is common for all
three reactor units. To maintain the proper
pressure conditions, an airtight partition was
Cable penetrations had been sealed
constructed between operating Units 1 and
after initial installation but additional cables
2, and Unit 3, while Unit 3 was under
were often added. To make an opening for
construction. It was necessary to determine
additional cables, holes were punched
that the standby gas-treatment system could
through the wall penetration sealing
handle the added inleakage from the Unit 3
materials and fire stop with a wooden stick.
reactor building before the partition between
This process resulted in pieces of
Units 2 and 3 could be removed. Leakage
polyurethane and flameastic (fire retardant
tests run on the Units 1 and 2 reactor
material) being knocked onto the cables on
buildings indicated that leakage had to be
both sides of the penetration.
reduced to a maintaining inleakage within
the requirements of the Units 1 and 2
In the early afternoon, an inspector
technical specifications when the partition
and an electrician were checking cable
was removed.
penetrations through the wall between the
cable spreading room and the Unit 1 reactor
The program undertaken to reduce
building. The inspector was using a candle
leakage required that all leaks be identified
flame to detect air leaks. The inspector
and listed, that leaks be sealed, and that
detected a strong air leak in the penetration
work be verified and signed off by an
for the second tray from the bottom on the
engineer. The method for detecting air
west row. The electrician experienced
leaks was left to the discretion of the
difficulty reaching the penetration to seal it
engineer in charge. Several methods had
because it was recessed into the wall farther
been employed including smoke devices,
than he could reach. The inspector
soap solutions, and candles. The movement
volunteered to seal the leak for the
or flickering of a candle flame was an
electrician. The electrician handed him
especially effective method for locating
pieces of resilient polyurethane foam sealing
leaks in dimly lighted areas and became the
material that the inspector inserted into the
method most used. As the number of leaks
hole.
After inserting the resilient
was reduced, the differential pressure across
polyurethane foam into the leak, the
the walls increased and penetrations that
inspector placed the candle about 1 inch
originally did not leak began to permit
from the resilient polyurethane foam to
leakage.
Therefore, the inspectors,
check the success of the repaired seal. The
accompanied by electricians who sealed
airflow through the leak pulled the candle
leaking penetrations as they were
flame into the resilient polyurethane foam,
discovered, were instructed to recheck all
which sizzled and began to burn. The
penetrations in their assigned areas.
inspector and the electrician attempted
unsuccessfully to put out the fire by
B-6
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