Headquarters Daily Report OCTOBER 28, 1997 *************************************************************************** REPORT NEGATIVE NO INPUT ATTACHED INPUT RECEIVED RECEIVED HEADQUARTERS û REGION I û REGION II û REGION III û REGION IV û PRIORITY ATTENTION REQUIRED MORNING REPORT - HEADQUARTERS OCTOBER 28, 1997 MR Number: H-97-0137 NRR DAILY REPORT ITEM GENERIC COMMUNICATIONS NRC Information Notice 97-76, "Degraded Throttle Valves in Emergency Core Cooling System Resulting from Cavitation-Induced Erosion During a Loss-of- Coolant Accident," dated October 30, 1997. The NRC is issuing this information notice to alert addressees to potential problems caused by degradation of emergency core cooling system (ECCS) throttle valves in the intermediate-head safety injection pump hot-leg and cold-leg flow paths and in the charging pump (high-head safety injection) cold-leg flow paths during certain loss-of-coolant-accident scenarios. Technical contacts: Chu-Yu Liang, NRR 301-415-2878 William F. Burton, NRR 301-415-2853 _ REGION II MORNING REPORT PAGE 2 OCTOBER 28, 1997 Licensee/Facility: Notification: Florida Power & Light Co. MR Number: 2-97-0079 Saint Lucie 1 Date: 10/28/97 Florida Dockets: 50-335 PWR/CE Subject: ST LUCIE UNIT 1 STUCK CONTROL ELEMENT ASSEMBLY DURING MOVEMENT OF UPPER GUIDE STRUCTURE Discussion: On October 27, 1997, while lifting the upper guide structure (UGS) from the Unit 1 reactor pressure vessel (RPV), the licensee noted a Control Element Assembly (CEA) lodged in the UGS and fully withdrawn from the core. At approximately 5:45 p.m., the UGS was being lifted in preparation for defueling the reactor. Once lifted, the licensee performed an underwater inspection of the bottom side of the UGS to determine if there were any interferences with other reactor internal components. During the inspection, the licensee identified a single CEA protruding from the lower end of the UGS. The CEA had apparently lodged in the UGS and had been lifted from the reactor core. The licensee immediately halted further UGS movement. At the time of the event, the containment equipment and personnel hatches were open to facilitate personnel and equipment access in preparation for the upcoming steam generator replacement. The licensee subsequently secured those penetrations and by 6:00 p.m. had reestablished containment. The licensee revised the normal reactor disassembly procedure to account for the additional height the UGS would have to be lifted for the CEA to clear the RPV wall. Additional measures were proceduralized to shield the essential personnel involved in the evolution. Shielding was provided for the polar crane operator and additional electronic dosimeters were placed throughout the haul route and continuously monitored. In addition, members of management, engineering, health physics, and operations, monitored the move from the technical support center via remote cameras and an underwater (submarine) camera. At approximately 3:20 a.m., October 28, as the UGS was lifted, a containment isolation occurred as expected. The UGS, with the CEA, was successfully moved to the UGS storage area. An attempt was made to dislodge the CEA by dragging the CEA against an underwater obstacle. (All this was observed via the submarine camera.) The CEA did not dislodge. While maneuvering the submarine camera, the power umbilical became tangled between two of the CEA rodlets. The licensee drove the submarine to the surface of the water, disconnected the power umbilical and secured a rope to end of the umbilical. The umbilical was then pulled back through the rodlets, with the rope. Once completed the rope was then used to agitate the CEA, at which time it became dislodged and fell. At the time it fell, the CEA was approximately one foot above the floor of the UGS storage area. The UGS was then moved and set on its storage pedestal to allow access to the CEA. The highest dose rate observed in the vicinity of the polar crane operator was approximately 400 mr/hour. The crane operator received 20/mr and a total dose of 50mr exposure for the evolution. The resident inspector responded to the site and witnessed the planning REGION II MORNING REPORT PAGE 3 OCTOBER 28, 1997 MR Number: 2-97-0079 (cont.) of the evolution, the approval of the procedure used, and the movement of the UGS/CEA. The licensee intends to secure the CEA and determine the root cause of the event. Regional Action: The resident inspectors responded onsite to the event and will continue to follow the licensee root cause determination. Contact: S. Rudisail (404)562-4512 _