ML102870338
| ML102870338 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 09/20/2010 |
| From: | Chris Miller - No Known Affiliation |
| To: | Office of Information Services |
| References | |
| FOIA/PA-2010-0116 | |
| Download: ML102870338 (1) | |
Text
Data Request #108 - Estimated vacuum achievable with purge fan It was reported by Dave Jones (former CR3 operator) that an event occurred in the late 1980's or early 1990's during which a purge exhaust fan was operating with the inlet purge valve closed. This resulted in a vacuum in the containment building. The exact date of the event could not be determined, so retrieving the RB pressure strip chart to determine the resulting RB pressure is not practical.
An alternate method of determining the resulting RB pressure is to estimate a "worst case" vacuum based on system performance. The CR3 purge fans (AHF-7A/7B) are Joy Manufacturing model 36-26.5-1770 axial vane fans. The fan curve for these units are contained in vendor manual VTMA 231 (curve attached). The design point for the fans is 25000 cfm @ 10" wg with a blade setting of 1. The fans are connected to the containment building through a series of ductwork, filters, and dampers, and exhaust to the atmosphere.
If the fan curve is extrapolated to dead head (no flow) conditions, the maximum total pressure developed by the fan is approximately 12" wg. If the pressure loss in the ventilation system is conservatively neglected, the maximum vacuum would be equal to the atmospheric pressure minus the total pressure imparted by the fan. Since 12" wg is equal to approximately 0.433 psi, the RB vacuum would have been less than 0.5 psi. If the maximum total pressure of the fan is doubled to account for uncertainty of the extrapolation method, the vacuum would have been less than 1 psi.
Craig Miller