Headquarters Daily Report AUGUST 01, 1996 *************************************************************************** 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 AUGUST 1, 1996 MR Number: H-96-0058 NRR DAILY REPORT ITEM SIGNIFICANT EVENTS Subject: REACTOR TRIP WITH COMPLICATIONS AT ARKANSAS NUCLEAR ONE, UNIT 1 The NRR/AEOD/RES Events Assessment Panel, on July 23, 1996, classified the reactor trip with steam generator dryout at Arkansas Nuclear One, Unit 1, as a Significant Event. The classification was based upon a reactor scram with complications. On May 19, 1996, a malfunction in the feedwater control circuitry caused a prompt reduction in the speed and corresponding output of Main Feed Pump A, resulting in a reactor trip on high reactor pressure. Six of the eight main steam safety valves on Steam Header B opened as designed, but one of the six failed to close after steam pressure dropped. The pressure in Once-Through Steam Generator A did not reach the main steam safety valves lift setpoint because of the reduced inventory in the steam generator as a result of Main Feed Pump A speed reduction. This resulted in lower-than-normal once-through steam generator initial pressure after the reactor trip. This also allowed more time for the turbine bypass valves to open and reduce the peak pressure. In accordance with plant procedures, the operators isolated Once-Through Steam Generator B, allowing it to boil dry through the open safety valve. Following reactor trip, normal feedwater flow was lost because of further feedwater control deficiencies. Emergency feedwater actuated as designed and provided a decay heat removal path through Once-Through Steam Generator A and the condenser. Shortly after, the condenser became unavailable due to an absence of gland-sealing steam (which comes only from Steam Header B which had been isolated), and decay heat removal proceeded through the atmospheric dump valves. After the stuck-open safety valve was identified, it was reseated and gagged shut. Once-Through Steam Generator B was then filled using emergency feedwater approximately 5 1/2 hours after it was allowed to boil dry. From this point, recovery of the plant proceeded without complications. Analysis of the effects of the temperature transient on the reactor vessel and on the Once Through Steam Generator B shell and tubes indicated that this equipment had not been adversely affected and the plant could be returned to operation. The steam safety valve that failed did so because maintenance on it had been improperly performed. A castellated nut at the top of the valve stem was to be held in place by a cotter pin through the nut and stem. The cotter pin had not been properly engaged with the nut and, as the valve discharged, the valve vibration permitted the nut to rotate down the threaded stem and come to rest on the top of the valve lifting lever. When the valve was closing, the nut against the lever prevented the stem from dropping, holding the valve open. An Augmented Inspection Team was dispatched to the site and the results of its inspection were published June 12, 1996 in NRC Inspection Report HEADQUARTERS MORNING REPORT PAGE 2 AUGUST 1, 1996 MR Number: H-96-0058 (cont.) 50-313/96-19. The event was briefed on June 12, 1996, in Operating Reactors Events Briefing 96-06, "Reactor Trip With Steam Generator Dry-Out (AIT)." Contact: T. Reis, Region IV/DRP (817) 860-8185 R. Benedict, NRR/DRPM/PECB (301) 415-1157 _ HEADQUARTERS MORNING REPORT PAGE 2 AUGUST 1, 1996 MR Number: H-96-0059 NRR DAILY REPORT ITEM GENERIC COMMUNICATIONS NRC Information Notice 96-43, "Failures of General Electric Magne-Blast Circuit Breakers," dated August 2, 1996. The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice to alert addressees to recent failures of General Electric 4.16 kV Magne-Blast circuit breakers at the Dresden Nuclear Power Station, Unit 3 caused by hardened grease and failures of Magne-Blast breakers to latch closed at the Salem Nuclear Generating Station and the Maine Yankee Atomic Power Plant. Technical contacts: D. Skeen, NRR K. Naidu, NRR (301) 415-1174 (301) 415-2980 A. Pal, NRR J. Shannon, Region I (301) 415-2760 (610) 337-5132 _ REGION III MORNING REPORT PAGE 3 AUGUST 1, 1996 Licensee/Facility: Notification: Commonwealth Edison Co. MR Number: 3-96-0081 Dresden 2 3 Date: 08/01/96 Morris,Illinois RESIDENT INSPECTOR Dockets: 50-237,50-249 BWR/GE-3,BWR/GE-3 Subject: OUT OF SERVICE (OOS)ERROR ON 4KV SWITCHGEAR Discussion: Control room operators identified an OOS tag that should have been hung on a control switch on a Unit 2 panel, but was instead hung on an identical control switch on a Unit 3 panel. The control switch was for a Unit 2 to Unit 3 cross tie breaker. There is a tie-breaker located on both the Unit 2 and Unit 3 4KV buses. The two tie breakers' control switch nameplates have identical descriptions on the control room panels "BUS 24-1 & BUS 34-1 TIE ACB." The OOS instructions were clear as to the specific location, i.e. "PNL 902-8, CONTROL ROOM [Unit 2 panel]"; however, the operator hung the tag on the 903-8 control room panel. No independent verification was performed nor was it required by station procedures. Since the control switch tag was considered an "information only" tag, independent verification was "N/A'D" in the OOS. The associated tie breaker was racked out and properly tagged. The control switch OOS tag was incorrectly hung on July 30 by a licensed operator and found about 23 hours later. All work on electrical switchgear was stopped until the tag was properly hung and verified. In addition, a complete reverification of the OOS on the 4KV switchgear was performed. At the time of event discovery, the station had just restarted work after a 4 day "stand-down" for work control problems including an electrical safety concern. Regional Action: The resident inspectors and the Dresden Branch Chief reviewed the licensee's short term corrective actions and verified, through discussions with craft personnel, that station electrical safety practices were being followed for work on the 4KV switchgear. Contact: P.L. HILAND (603)829-9603 _ REGION IV MORNING REPORT PAGE 4 AUGUST 1, 1996 Licensee/Facility: Notification: Entergy Operations, Inc. MR Number: 4-96-0085 Arkansas Nuclear 1 2 Date: 08/01/96 Russelville,Arkansas Telephone Call from Licensee Dockets: 50-313,50-368 PWR/B&W-L-LP,PWR/CE Entergy Operations, Inc. Waterford 3 Killona,Louisiana Dockets: 50-382 PWR/CE Subject: MEMORANDUM OF UNDERSTANDING BETWEEN ENTERGY OPERATIONS, INC. AND NEW YORK POWER AUTORITY Discussion: On July 31, 1996, it was announced that the New York Power Authority (NYPA) and the Entergy Corporation of New Orleans had entered a Memorandum of Understanding (MOU) regarding the intent for Entergy to provide management services to two of NYPA's plants, Indian Point 3 and Fitzpatrick. The MOU was created to establish a three step process for the eventual issuance of a service contract between Entergy and NYPA. The three steps include: (1) visits to the sites by Entergy personnel to perform onsite due diligence reviews, (2) assessment of the data obtained during the site visits by NYPA and Entergy, and (3) commencement of a 5-year management services contract. It is anticipated that the onsite assessments will begin about August 19, 1996. Regional Action: For information only. Contact: P. H. Harrell (817)860-8250 _