ML052840344
| ML052840344 | |
| Person / Time | |
|---|---|
| Site: | Byron  (NPF-037) |
| Issue date: | 10/06/2005 |
| From: | Chrzanowski D Exelon Corp |
| To: | Dick G Office of Nuclear Reactor Regulation |
| References | |
| Download: ML052840344 (3) | |
Text
I George Dick - PRT ISSUES Pia'ge 1 1 GereDc R SUSPg From:
<david.chrzanowski @exeloncorp.com>
To:
<gfd~nrc.gov>
Date:
10/6/05 6:53PM
Subject:
PRT ISSUES Action Required: FYI Recommendation:
George -
Here is a write-up on the pressurizer relief tank it needs work but I think covers the concerns. Depending on the schedule for completion, Joe may be able to offer some suggestions.
<<prt.doc>>>
David Chrzanowski Licensing Engineer Exelon Nuclear - Cantera phone (630) 657-2816 pager (630) 683-0535 cell phone (630) 826-0604 fax - (630) 657-4327 This e-mail and any of its attachments may contain Exelon Corporation proprietary information, which is privileged, confidential, or subject to copyright belonging to the Exelon Corporation family of Companies.
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<joseph.bauer@ exeloncorp.com>
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PRT ISSUES 10/6/05 6:53PM
<david.chrzanowski @exeloncorp.com>
david.chrzanowski @ exeloncorp.com Recipients nrc.gov owf4_po.OWFNDO GFD (George Dick) exeloncorp.com joseph.bauer CC Post Office owf4_po.OWFNDO Files MESSAGE TEXT.htm prt.doc Mime.822 Options Expiration Date:
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Route nrc.gov exeloncorp.com Size 1294 3563 21504 37083 Date & Time 10/06/05 06:53PM None Standard No None No Standard
George Dick - prt.docP Page 1 The individual is concerned that the ability to bleed and feed the Byron Station, Unit 1 pressurizer relief tank (PRT) may be degraded and as a result, the capability to use the pressurizer power operated relief valves to cooldown and depressurize the RCS during a natural recirculation procedure could be compromised. The individual states that difficulties in filling and draining the Byron Station, Unit 1 PRT were the basis of a previous NRC allegation. However, in a January 30, 2004 response to this allegation, the licensee concluded that the concern that primary water flow to the PRT was below design was not validated.
The PRT is designed to absorb a discharge of steam equivalent to 110% full power pressurizer steam volume without exceeding pressure and temperature design values.
This steam volume is based a loss of load event accompanied by a turbine trip without the resulting direct reactor trip. The total volume of steam vented from the pressurizer to depressurize the plant from a hot standby to a cold shutdown condition is approximately that produced during the loss of load event; however, the rate of release is significantly lower and can be controlled to ensure that the integrity of the PRT is maintained. Since the loose-part scenario involves a non-accident, controlled shutdown, the depressurization operation can be managed to accommodate PRT draining.
While not desirable, and unacceptable per the licensee' operating procedures, if a discharge results in a pressure that exceeds the PRT design, the rupture discs on the tank would pass the discharge through the tank to the containment drains and would not impair the capability for safe plant shutdown.