Headquarters Daily report JULY 12, 1994 *************************************************************************** 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 II JULY 12, 1994 Licensee/Facility: Notification: Tennessee Valley Authority MR Number: 2-94-0056 Sequoyah 1 2 Date: 07/12/94 Soddy-Daisy,Tennessee Dockets: 50-327,50-328 PWR/W-4-LP,PWR/W-4-LP Subject: HEAVY RAINS CAUSED FLOODING OF A PORTION OF THE TURBINE BUILDING Reportable Event Number: N/A Discussion: On the morning of July 11, 1994, heavy rains over a short period of time caused flooding of a portion of the turbine building (TB) railroad bay, causing the 480v TB MOV Board 1A and 250VDC TB Distribution Panel to become wetted. Estimated rainfall was 4-6 inches of rain over a 2-3 hour period. The boards are on a level located beneath the railroad bay, and supply power to various balance of plant loads, e.g., feedwater heater control, MFWP control oil pump power supply. No actual plant loads were affected. In response to the potential affect on balance of plant equipment, Unit 1 load was reduced to approximately 80% as a precautionary measure. The purpose of the load reduction was such that the unit would be more likely to withstand a secondary side transient. The cabinet doors were subsequently opened and fans placed in the general area to assist in drying out the water. Additional corrective actions are being evaluated regarding the prevention of drain water in the area and checkout of the boards. Licensee management will determine today when Unit 1 will resume full power operations. Regional Action: Resident Inspector followup on corrective action. Contact: Mark S. Lesser (404)331-0342 PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION III JULY 12, 1994 Licensee/Facility: Notification: Cleveland Electric Illuminating Co. MR Number: 3-94-0125 Perry 1 Date: 07/12/94 Perry,Ohio SRI VIA PC Dockets: 50-440 BWR/GE-6 Subject: LOSS OF SHUTDOWN COOLING Reportable Event Number: 27521 Discussion: On July 11, 1994, at about 9:54 p.m., the residual heat removal (RHR) shutdown cooling suction valve (common to both normal shutdown cooling loops) unexpectedly closed during a post-maintenance pressure test (1200 psig) of a replacement isolation valve for a pressure transmitter. There did not appear to be any warning in the work order and referenced instructions that pressurizing the replaced valve would cause the suction valve to close (isolation setpoint is 135 psig). The operators observed an "RHR Suction Pressure Low" annunciator, decreasing RHR pump flow, and intermediate position indication for the common suction valve and manually tripped the pump when it did not trip due to suction valve closure. The licensee restored normal shutdown cooling in 53 minutes (after filling and venting the system). Indicated reactor coolant temperature increased from 100.3 degrees F. to 102 degrees F. and recirculation pump B remained in service in slow speed throughout the event. When the suction valves were reopened as part of the filling and venting evolution, reactor pressure vessel level indication dropped about 11 inches. The causes for the RHR pump not tripping and for the level drop are being investigated and the licensee is evaluating the possibility that a water hammer occurred when the RHR suction piping was refilled; however, they do not currently believe that a water hammer occurred. Regional Action: The senior resident inspector responded to the control room and the inspectors are continuing to evaluate the licensee's root cause evaluation and corrective actions. Contact: ROGER LANKSBURY (708)829-9631