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UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF NUCLEAR REACTOR REGULATION WASHINGTON, D.C. 20555 November 4, 1991 NRC INFORMATION NOTICE 91-70: IMPROPER INSTALLATION OF INSTRUMENTATION MODULES Addressees All holders of operating licenses or construction permits for nuclear power reactors. Purpose The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice to alert addressees regarding the possible improper installation of instrumentation modules that could result in inadequate seismic qualification of instrument cabinets. 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 are not NRC requirements; therefore, no specific action or written response is required. Description of Circumstances By letter of August 29, 1991, Entergy Operations, Inc., the licensee for the Arkansas Nuclear One facility, notified the NRC that it had identified that certain instrument modules located in the safety-related Foxboro instrument cabinets did not have vibration-dampening material installed. The licensee also noted that the instrument module guide rails were not installed for some of the modules and that some of the power supply brackets were missing. Through an engineering evaluation and contact with the vendor, the licensee determined that the cabinets and the instrumentation modules were not seismically qualified in the condition in which they were found. This finding prompted the licensee to declare the affected cabinets inoperable. The licensee took immediate action to place the plant in a Hot Shutdown condition in accordance with the technical specification requirements. Discussion The licensee reviewed the events leading up to the discovery of the improper installation of the instrumentation modules and found that it had purchased the Foxboro Specification 200 instrument nests and modules in 1984 as separate parts and arranged for their assembly at the site by the licensee's general contractor. In addition, another contractor assembled similar equipment offsite and then shipped it to the site for installation. It was noted that the vendor had shipped the subject vibration-dampening material, guide rails, and power supply brackets with the equipment. However, the shipping package did not include a parts list or any specific installation instructions for 9110300195 . IN 91-70 November 4, 1991 Page 2 of 2 these components. While the licensee did procure the applicable vendor manuals, the manuals applied to the general line of Specification 200 equipment and did not address the special instructions for Class IE equipment since at that time Foxboro had not as yet developed the pertinent instructions. Also, the vendor's documentation did not include detailed installation drawings. A paragraph in the Class IE qualification test results indicated that the standard modules would need to be modified to meet seismic qualifications. However, the test report did not provide specific instructions for such a modification, and the licensee's review was not adequate to identify the need. In addition, the contractor personnel did not inquire regarding the purpose of the additional parts included in the shipping package. This information notice requires no specific action or written response. If you have any questions about the information in this notice, please contact the technical contact listed below or the appropriate Office of Nuclear Reactor Regulation (NRR) project manager. Charles E. Rossi, Director Division of Operational Events Assessment Office of Nuclear Reactor Regulation Technical contact: Walter P. Haass, NRR (301) 492-3219 Attachment: List of Recently Issued NRC Information Notices .
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