05000254/FIN-2011009-04
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Finding | |
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| Title | Tornado Missile Protection of the Emergency Diesel Generator Air Intake and Exhaust |
| Description | During a walkdown of the 1/2 EDG, the inspectors observed that the diesel exhaust silencer and air intake vent are mounted on the roof of the building and are not protected from tornado missiles by concrete structures. The safety evaluation report for the construction permit of the Quad Cities Station states: Since the proposed site is in an area of relatively high tornado frequency, components which are required for safe shutdown of the plant will be located either under the protection of reinforced concrete or located underground. The Quad Cities Station UFSAR Section 3.1.1.2 also states: Section 3.1.1.2 Criterion 2 - Performance Standards Those systems and components of reactor facilities which are essential to the prevention of accidents which could affect the public health and safety or to mitigation of their consequences shall be designed, fabricated, and erected to performance standards that will enable the facility to withstand, without loss of the capability to protect the public, the additional forces that might be imposed by natural phenomena such as earthquakes, tornadoes, flooding conditions, winds, ice, and other local site effects. The design bases so established shall reflect: (a) appropriate consideration of the most severe of these natural phenomena that have been recorded for the site and the surrounding area, and (b) an appropriate margin for withstanding forces greater than those recorded to reflect uncertainties about the historical data and their suitability as a basis for design. -Response- The plant equipment which is important to safety is designed to permit safe plant operation and to accommodate all design basis accidents for all appropriate environmental phenomena at the site without loss of their capability, taking into consideration historical data and suitable margins for uncertainties. This information prompted the inspectors to question whether the diesel generator systems were installed in accordance with the Quad Cities licensing basis. The licensee responded that the design had been previously approved and reviewed for the Dresden Station (the representative plant for Quad Cities) during the NRC Systematic Evaluation Program (SEP) as documented in NUREG-0823, Integrated Plant Safety Assessment, Systematic Evaluation Program, Dresden Nuclear Power Station Unit 2. In this document the NRC determined that Dresden must protect the diesel air intakes and exhaust, however, NUREG-0823 Supplement 1, documents NRC acceptance of a probability analysis for Dresden in lieu of protection. The licensee further stated that the issue of tornado missile protection was resolved through issuance of Generic Letter 95-04, Final Disposition of the Systematic Evaluation Program Lessons-Learned Issues. The inspectors were unable to determine during the inspection if the Quad Cities licensing basis required the EDG intake and exhaust to be protected from tornado missiles. Therefore, this concern will be considered an unresolved item |
| Site: | Quad Cities  |
|---|---|
| Report | IR 05000254/2011009 Section 1R21 |
| Date counted | Dec 31, 2011 (2011Q4) |
| Type: | URI: |
| cornerstone | Mitigating Systems |
| Identified by: | NRC identified |
| Inspection Procedure: | IP 71111.21 |
| Inspectors (proximate) | Z Falevits S Sheldon W Sherbin D Melendez-Colon C Brown N Feliz-Adomo A Stone J Chiloyen |
| INPO aspect | |
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Finding - Quad Cities - IR 05000254/2011009 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Finding List (Quad Cities) @ 2011Q4
Self-Identified List (Quad Cities)
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