9/10/14 Power Reactor Event Number: 49879 Facility: DIABLO CANYON Region: 4 State: CA Unit: [1] [2] UNANALYZED CONDITION REGARDING POTENTIAL TORNADO MISSILE DAMAGE TO EMERGENCY DIESEL EXHAUST PLENUM The condition described below is being reported as an unanalyzed condition per 10 CFR 50.72(b)(3)(ii)(B) and per the guidance of NUREG-1022, Rev. 3. On 03/06/2014 at 0906 PST, Diablo Canyon Power Plant (DCPP) identified a nonconforming condition involving the Emergency Diesel Generator (EDG) ventilation exhaust plenums installed in Unit 1 and Unit 2. Specifically, the radiator exhaust plenums and exhaust piping need to be re-evaluated to ensure adequate protection against flying debris that could be generated by a tornado. The occurrence of such an event is highly unlikely and there is no imminent concern regarding severe weather involving tornados. The EDGs are located inside the power plant structure and are capable of performing their safety function. Compensatory measures are being developed to address the associated nonconformance. This event does not adversely affect the health and safety of the public. The licensee informed the NRC Resident Inspector. * * * UPDATE PROVIDED BY RUSS CRUZEN TO JEFF ROTTON AT 2245 EDT ON 09/09/2014 * * * This condition does not adversely affect the health and safety of the public. Based on an extent of condition review being performed for this event, the issue identified in the original event notification 49879 has also been determined to similarly affect the ventilation systems associated with the Unit 1 and 2 Vital 480 volt AC switchgear and battery/inverter equipment. The condition described in this update is being reported as an unanalyzed condition per 10 CFR 50.72(b)(3)(ii)(B) and as an event or condition that could have prevented the fulfillment of a safety function per 10 CFR 50.72(b)(3)(v)(A). Compensatory measures are being developed to address the associated condition. The licensee informed the NRC Resident Inspector. Notified R4DO (Azua) Part 21 Event Number: 50439 Rep Org: CAMERON MEASUREMENT SYSTEMS Licensee: CAMERON MEASUREMENT SYSTEMS Region: 4 City: CITY OF INDUSTRY State: CA PART 21 REPORT - DEFECTIVE BARTON DIFFERENTIAL PRESSURE SWITCHES The following is a synopsis of information received via facsimile: Cameron Measurement Systems has issued a product advisory concerning nuclear qualified versions of Barton Model 288A, 289A, 580A and 581A differential pressure indicating switches and blind switches and spare switch assemblies shipped from the Cameron factory. The defect being reported is an out of specification thread on the screws that depress the switch operating plunger which can cause a change in the switch setpoint. The maximum change in screw position observed during testing equates to a switch set point change of approximately 8.4 percent of the instruments factory calibrated span. The screws of concern did not enter the Cameron stock before February of 2014 for the ones used in the Model 580A and 581A instruments and not before June of 2014 for the ones used in Model 288A and 289A instruments. Cameron recommends that new switch actuator arm assemblies be replaced on any unit that is evaluated to be a concern by their customers. Notification to NRC provided by ISAAC RAMSINI, Manager Quality and Safety, (562) 321-9158. And other reportable events... nrc.gov/reading-rm/doc-collections/event-status/event/en.html
Posted on: Wed, 10 Sep 2014 11:47:41 +0000
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