Morning Report for February 24, 1999
Headquarters Daily Report FEBRUARY 24, 1999 *************************************************************************** REPORT NEGATIVE NO INPUT ATTACHED INPUT RECEIVED RECEIVED HEADQUARTERS X REGION I X REGION II X REGION III X REGION IV X PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION III FEB. 24, 1999 Licensee/Facility: Notification: Commonwealth Edison Co. MR Number: 3-99-0011 Quad Cities 2 Date: 02/24/99 Cordova,Illinois E-Mail Dockets: 50-265 BWR/GE-3 Subject: INADVERTENT DRAINDOWN OF ABOUT 6000 GAL. REACTOR WATER TO TORUS Discussion: 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 event. 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. Regional Action: 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 Licensee/Facility: Notification: Entergy Operations, Inc. MR Number: 4-99-0006 Arkansas Nuclear 2 Date: 02/24/99 Russelville,Arkansas Licensee Requested NOED Dockets: 50-368 PWR/CE Subject: NOTIFICATION OF ENFORCEMENT DISCRETION TO PERMIT STARTUP Discussion: 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 3.3.1.1, 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. Regional Action: Routine resident inspection. Contact: David Loveless (817)860-8161 _
Page Last Reviewed/Updated Wednesday, March 24, 2021
Page Last Reviewed/Updated Wednesday, March 24, 2021