Morning Report for February 24, 1999
Headquarters Daily Report
FEBRUARY 24, 1999
REPORT NEGATIVE NO INPUT
ATTACHED INPUT RECEIVED RECEIVED
REGION I X
REGION II X
REGION III X
REGION IV X
PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION III FEB. 24, 1999
Commonwealth Edison Co. MR Number: 3-99-0011
Quad Cities 2 Date: 02/24/99
Subject: INADVERTENT DRAINDOWN OF ABOUT 6000 GAL. REACTOR WATER TO TORUS
Unit 2 was in cold shutdown with reactor water temperature at about 144
degrees Fahrenheit and reactor water level in a band of 90 to 94 inches
indicated level (normal level during operations is 30 inches indicated.)
Core cooling was being maintained in a band of 120 to 170 degrees
Fahrenheit by the "A" loop of shutdown cooing, after being switched from
the "B" loop at about 00:32 a.m. (CST). At about 01:02 a.m., operators
noted a decreasing reactor water level, and secured the "2A" residual
heat removal pump which stopped shutdown cooling operations.
Water level continued to decrease, but at a much slower rate once the
pump was secured. Operators then found that the minimum flow valve for
the "2A" residual heat removal pump was not closed, as required by
procedure; but was instead fully open with the breaker for the valve
de-energized. This had allowed a drain path from the reactor, through
shutdown cooling piping, into the suppression pool. The licensee
estimated that about 6000 gallons of reactor vessel water were drained to
the suppression pool.
At 01:55 a.m. operators restored the "2A" loop of shutdown cooling to the
proper lineup and started the "2A" residual heat removal pump. Water
level had decreased to about 50 inches indicated. Forced circulation
using a reactor recirculation pump remained in effect throughout the
The licensee began a prompt investigation, and removed the operators from
shift who were responsible for the event. Operators are being sent to the
simulator to review the event and discuss better means of control for
evolutions in the control room. ComEd management is planning to send a
corporate led team to the site to assist in the root cause investigation
of the event.
The resident inspectors responded to the control room, ensured plant
conditions were stable and began a review of the causes for the event and
the licensee's corrective actions.
Contact: M. Ring (630)829-9703
REGION IV MORNING REPORT PAGE 2 FEBRUARY 24, 1999
Entergy Operations, Inc. MR Number: 4-99-0006
Arkansas Nuclear 2 Date: 02/24/99
Russelville,Arkansas Licensee Requested NOED
Subject: NOTIFICATION OF ENFORCEMENT DISCRETION TO PERMIT STARTUP
On February 23, 1999, at 9:02 p.m. EST, NRR granted a Notification of
Enforcement Discretion to permit restart of Arkansas Nuclear One, Unit 2,
from their 13th refueling outage. Specifically, discretion was granted
from a Technical Specification 188.8.131.52, Action 2, requirement that the
Channel D neutron detection instrumentation be returned to operable
status prior to startup. Additionally, discretion was granted from the
requirements of Technical Specification 3.0.4 that prevented changing
modes while relying on Action Statement 2. The discretion will remain in
effect until the licensee's request for an exigent Technical
Specification amendment is reviewed, authorized, and implemented.
During the last operating cycle, the reactor protective system Channel D
wide-range neutron detector string upper detector had failed. Operators
had placed the affected reactor protective system trips in bypass and
continued operation as permitted by Technical Specifications. Channel D
is one of four redundant protective system channels. The Unit 2 plant
protective system logic is designed for operation as a 2-out-of-3 logic,
although it is normally operated in a 2-out-of-4 mode. Technical
Specifications required the licensee to return the failed channel to an
operable status prior to startup following the next cold shutdown.
During the current refueling outage, instrumentation and controls
technicians had installed a spare detector string and performed
appropriate postmaintenance testing. However, during the plant heatup,
the middle detector failed to respond properly to the change in neutron
leakage. The licensee determined that either the detector or associated
cabling had failed and that no replacement detector string was available.
Therefore, the licensee requested discretion in accordance with
NUREG 1600, Part 9900, "Technical Guidance," paragraph 2.3.a, because the
three required channels were operable.
Relying on the discretion, licensed operators made the reactor critical
at 6:35 a.m. this morning.
Routine resident inspection.
Contact: David Loveless (817)860-8161
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