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UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REACTOR REGULATION WASHINGTON, D.C. 20555 April 21, 1989 Information Notice No. 89-42: FAILURE OF ROSEMOUNT MODELS 1153 AND 1154 TRANSMITTERS Addressees: All holders of operating licenses or construction permits for nuclear power reactors. Purpose: This information notice is being provided to alert addressees about recent failures of Rosemount models 1153 and 1154 pressure and differential pressure transmitters. It is expected that recipients will review the information for applicability to their facilities and consider actions, as appropriate, to avoid similar problems. However, suggestions contained in this information notice do not constitute NRC requirements; therefore, no specific action or written response is required. Description of Circumstances: During 1986 and 1987, five Rosemount model 1153 HD5PC differential pressure transmitters malfunctioned at Northeast Utilities' (NU) Millstone Nuclear Power Station, Unit 3. During power operation, the Millstone operators noted that the signals from the Rosemount 1153 transmitters were deviating from redundant channel signals and that the transmitters were indicating reduced levels of process noise. The transmitters were declared out of service by NU personnel, and the affected channels were placed in the tripped condition. After attempts to calibrate the transmitters failed, NU returned the trans- mitters to Rosemount and informed them that the malfunctions had occurred with transmitters of the same model and related serial numbers. Destructive testing performed by Rosemount determined that the failures were caused by the loss of oil from the transmitter's sealed sensing module. However, Rosemount indicated that the failures appeared to be random and not related to any generic problem with Rosemount 1153 pressure transmitters. NU submitted a 10 CFR Part 21 notification to the NRC on this issue on March 25, 1988, and provided additional information on the failures via a letter dated April 13, 1989. Discussion: After additional evaluations by NU and Rosemount, Rosemount issued a letter to its customers on December 12, 1988, regarding the potential malfunction of models 1153 and 1154 pressure and differential pressure transmitters. The 8904180193 .. IN 89-42 April 21, 1989 Page 2 of 3 Rosemount letter was supplemented with a letter dated February 7, 1989, to customers who had purchased transmitters from specific lots that were identi- fied by Rosemount as being potentially defective. Rosemount issued a separate letter dated February 16, 1989, to customers who had purchased model 1153 and 1154 transmitters from lots that were not considered suspect. Rosemount indi- cated that transmitters from the suspect lots were susceptible to a loss of silicone oil from the transmitter sealed sensing module and to possible fail- ure. According to Rosemount, as the oil leaks out of the sensing module the transmitter's performance gradually deteriorates and may eventually lead to a detectable failure. Some of the symptoms that have been observed during operation and before failure include slow drift in either direction of about 1/4 percent or more per month, lack of response over the transmitter's full range, increase in the transmitter's time response, deviation from the normal signal fluctuations, decrease in the detectable noise level, deviation of signals from one channel compared with redundant channels, "one sided" signal noise, and slow response to a transient or inability to follow a transient. Some of the symptoms observed by NU personnel during calibration include the inability to respond over the transmitter's entire range, slow response to either increasing or decreasing hydraulic test pressure, and drift of greater than 1% from the previous calibration. Although some of the defective transmitters have shown certain symptoms before their failure, it has been reported that in some cases the failure of a trans- mitter may not be detectable during operation. In addition, Rosemount now indicates that the potential for malfunction may not be limited to the speci- fied manufacturing lots previously identified in the February 1989 letter. It is important for addressees to determine whether any Rosemount models 1153 and 1154 pressure and differential pressure transmitters, regardless of their manufacturing date, are installed in their facilities and to take whatever actions are deemed necessary to ensure that any potential failures of these transmitters are identified. Although it may not be possible to detect the onset of failure in all instances, some transmitters have exhibited some of the aforementioned symptoms before failure. It is important for potential failure modes to be identified and that operators be prepared for handling potential malfunctions. In addition, careful examination of plant data, calibration records, and operating experience may yield clues that identify potentially defective transmitters. Addressees may wish to contact Rosemount for assistance in determining appropriate corrective actions whenever any of the aforementioned symptoms are observed or if failures are identified. On April 13, 1989, the NRC staff met and discussed this matter with Rosemount and several industry groups. Rosemount has launched a program to identify the root cause of the loss of oil from the sensing module and to determine recom- mendations for its customers to address potentially defective transmitters. .. IN 89-42 April 21, 1989 Page 3 of 3 No specific action or written response is required by this information notice. If you have any questions regarding this matter, please contact one of the technical contacts listed below or the Regional Administrator of the appro- priate regional office. Charles E. Rossi, Director Division of Operational Events Assessment Office of Nuclear Reactor Regulation Technical Contacts: Kamal Naidu, NRR (301) 492-0980 Jaime Guillen, NRR (301) 492-1170 Attachment: List of Recently Issued NRC Information Notices .. Attachment IN 89-42 April 21, 1989 Page 1 of 1 LIST OF RECENTLY ISSUED NRC INFORMATION NOTICES _____________________________________________________________________________ Information Date of Notice No._____Subject_______________________Issuance_______Issued to________ 89-41 Operator Response to 4/20/89 All holders of OLs Pressurization of Low- or CPs for nuclear Pressure Interfacing power reactors. Systems 88-75, Disabling of Diesel 4/17/89 All holders of OLs Supplement 1 Generator Output Circuit or CPs for nuclear Breakers by Anti-Pump power reactors. Circuitry 89-40 Unsatisfactory Operator Test 4/14/89 All holders of OLs Results and Their Effect on or CPs for nuclear the Requalification Program power reactors. 89-39 List of Parties Excluded 4/5/89 All holders of OLs from Federal Procurement or CPs for nuclear or Non-Procurement Programs power reactors. 89-38 Atmospheric Dump Valve 4/5/89 All holders of OLs Failures at Palo Verde or CPs for nuclear Units 1, 2, and 3 power reactors. 89-37 Proposed Amendments to 4/4/89 All U.S. NRC 40 CFR Part 61, Air licensees. Emission Standards for Radionuclides 89-36 Excessive Temperatures 4/4/89 All holders of OLs in Emergency Core Cooling or CPs for nuclear System Piping Located power reactors. Outside Containment 88-86, Operating with Multiple 3/31/89 All holders of OLs Supp. 1 Grounds in Direct Current or CPs for nuclear Distribution Systems power reactors. 89-35 Loss and Theft of Un- 3/30/89 All U.S. NRC secured Licensed Material byproduct, source and special nuclear material licensees. _____________________________________________________________________________ OL = Operating License CP = Construction Permit ..
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