Headquarters Daily report SEPTEMBER 29, 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 - HEADQUARTERS SEP. 29, 1994 MR Number: H-94-0089 NRR DAILY REPORT ITEM GENERIC COMMUNICATIONS BRANCH/EVENTS ASSESSMENT BRANCH DIVISION OF OPERATING REACTOR SUPPORT OFFICE OF NUCLEAR REACTOR REGULATION Subject: N/A NRC Information Notice 94-71, "Degradation of Scram Solenoid Pilot Valve Pressure and Exhaust Diaphragms," to be issued October 4, 1994. The NRC is issuing this information notice to alert addressees to the potential failure of scram solenoid pilot valve diaphragms to function properly to the end of their recommended service life. Technical contacts: Kamalakar Naidu, NRR Joseph Petrosino, NRR (301) 504-2980 (301) 504-2979 Harold Ornstein, AEOD David Skeen, NRR (301) 415-7574 (301) 504-1174 NRC Information Notice 94-72, "Increased Control Rod Drop Time from Crud Buildup," to be issued October 5, 1994. The NRC is issuing this information notice to alert addressees to potential problems resulting in increase of control rod drop times caused by the buildup of crud in control rod drive mechanisms designed by the Babcock and Wilcox Company (B&W). Technical contacts: Thomas Koshy, NRR Howard Richings, NRR (301) 504-1176 (301) 504-2888 PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION SEPTEMBER 29, 1994 MR Number: H-94-0090 NRR DAILY REPORT ITEM SIGNIFICANT EVENTS EVENTS ASSESSMENT BRANCH DIVISION OF OPERATING REACTOR SUPPORT Subject: Reactor Trip with Subsequent Safety Injection and Solid Reactor Coolant System The NRR/AEOD Events Assessment Panel on September 20, 1994, classified the reactor trip with complications at Salem, Unit 1 as a Significant Event for the NRC Performance Indicator Program. On April 7, 1994, operators at Salem, Unit 1 were operating the unit at 73 percent power. The plant was at a reduced power level due to a reduction in condenser cooling efficiency resulting from river grass clogging the unit's condenser circulating water intake-structure travelling-screens. Shortly after 10:00 a.m., a severe grass intrusion occurred at the intake structure, and many of the Unit 1 circulating water pumps began to trip. Operators conse- quently began to reduce plant power to take the unit off line. As a result of operator error and equipment complications, a Unit 1 reactor trip occurred (High neutron flux-low setpoint) due to control rods being withdrawn to regain reactor coolant temperature, an automatic safety injection occurred (high steam flow coincident with low primary coolant Tavg due to the pre-existing low primary coolant Tavg and a short duration steam line pressure pulse which was interpreted as high steam flow, and a second automatic safety injection occurred (low reactor coolant pressure) due to a primary system cooldown caused by open secondary code safety valves. The subsequent sequence of events resulted in primary coolant system overfill, loss of normal pressurizer pressure control, and frequent cycling of power-operated relief valves. The licensee declared an Unusual Event and an Alert. An Augmented Inspection Team (AIT) was dispatched to the site to review the event. The AIT noted weaknesses in the licensee's command and control, corrective actions for pre-existing hardware deficiencies, procedures for abnormal plant conditions, and design and material control. The AIT findings are documented in Inspection Report 50-272/94-80 and 50-311/94-80. The Probabilistic Safety Assessment Branch (SPSB) considered the risk implications of the event and the feasibility of conducting a quantitative analysis. Since the risk significant aspects of this event primarily result from human errors of commission (operator error defeating the running high head safety injection system subsequent to a primary power-operated relief valve or safety valve sticking open), SPSB believes that currently available PRA models or techniques would not adequately capture the risk significance in a quantitative analysis. Information Notice 94-36, "Undetected Accumulation of Gas in Reactor Coolant System," has been issued and it discusses a gas bubble that was found in the reactor vessel head after the plant trip. Information Notice 94-55, "Problems with Copes-Vulcan Pressurizer Power-Operated Relief Valves," has been issued and it discusses power-operated relief valve deficiencies. CONTACT: Eric Benner, NRR/DORS/OEAB (301) 504-1171 PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION III SEPTEMBER 29, 1994 Licensee/Facility: Notification: Northern States Power Co. MR Number: 3-94-0173 Monticello 1 Date: 09/28/94 Monticello,Minnesota phone notification to drss Dockets: 50-263 BWR/GE-3 Subject: unplanned intakes of americium-241 Reportable Event Number: N/A Discussion: On September 27, 1994, sixteen outage workers had unplanned, suspected intakes of americium-241 (Am-241), which primarily emits alpha radiation. Currently in a 40 day refueling outage, the licensee was performing replacement of 4 outboard main steam isolation valves (MSIVs). The workers had completed surface preparation of the first three steam lines and were in the process of grinding the inner diameter of the fourth steam line. Based on contamination surveys of the pipe surfaces and an ALARA review, the licensee had determined that no respiratory protection was necessary for the grinding evolution. Two high efficiency particulate air filtration units were used for air purification. Air samples taken throughout the grinding of the first three steam lines did not indicate any airborne hazard. During the grinding of the final steam line, the first breathing zone air sample indicated an Am-241 concentration of 6.12 X 10-10 microcuries/cc (2.27 X 10-5 becquerels/cc) or 204 derived air concentration (DACs). The sum of all other radionuclides (i.e. cobalt-60, manganese-54, and zinc-65) was less than 0.5 DAC. The licensee immediately stopped the evolution and removed the workers from the area. No internal contamination was detected on whole body counts; however, the low energy gamma radiation would be very difficult to detect. The licensee was in the process of obtaining a more sensitive detector to perform additional whole body counting. The licensee had begun collecting urine specimens for in-vitro bioassay measurements (on a voluntary basis). Based on the initial air sample and the one hour duration of the activity, the maximum postulated dose to each worker was 5.1 rem (51 millisieverts) committed dose equivalent (CDE) to the bone surface (limiting organ), compared to a 50 rem (500 millisievert) 10 CFR 20.1201 occupational dose CDE limit, and 0.27 rem (2.7 millisieverts) committed effective dose equivalent (CEDE). No regulatory dose limits appear to have been exceeded. The licensee continues to evaluate the source of the Am-241 in the oxide layer of the main steam line. Regional Action: A regional radiation specialist will follow-up on licensee's dose evaluations and additional corrective actions. Contact: s. orth (708)829-9827 PRIORITY ATTENTION REQUIRED MORNING REPORT - REGION III SEPTEMBER 29, 1994 Licensee/Facility: Notification: Hull And Associates MR Number: 3-94-0174 N/A Date: 09/28/94 Toledo,Ohio phone call from licensee Dockets: 03029977 License No: 34-24957-01 Subject: damaged moisture density gauge Reportable Event Number: N/A Discussion: At approximately 4:00 p.m. on September 28, 1994, a CPN Model MC Series moisture density gauge containing a nominal 10 millicurie (370 MBq) cesium-137 sealed source and a 50 millicurie (1850 MBq) americium-241 sealed source was damaged at the Tremont Landfill in Clark County, Ohio (near Springfield, Ohio). A earthmover ran over the gauge after the vehicle drove over the top of a berm at the landfill. The gauge operator just escaped injury by moving out of the path of the earthmover. The gauge operator stopped the earthmover and isolated a 500 foot area around the damaged gauge. A manufacturer representative responded to the accident and was able to return the source rod to its shielded position. Visual examination of the gauge revealed a smashed housing and a bent source rod, but there was no physical damage to the sealed sources. Radiation surveys of the area and earthmover showed no radiation above background levels. The damaged gauge was packaged in its shipping container and returned to storage at the manufacturer's repair facility in Stoutsville, Ohio. Gross wipe test results showed no contamination from the sealed sources. NMSS and the State of Ohio have been notified of this incident. Regional Action: Region 3 will followup on this incident during a future inspection. Contact: w.p. reichhold (708)829-9839 b.j. holt (708)829-9836