ML082530309

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Vermont Yankee July 2008 Evidentiary Hearing - Applicant Exhibit E4-16-VY, INPO Report OE-17654 (Clinton)
ML082530309
Person / Time
Site: Vermont Yankee, Clinton  File:NorthStar Vermont Yankee icon.png
Issue date: 08/12/2008
From:
AmerGen Energy Co, Entergy Nuclear Operations, Entergy Nuclear Vermont Yankee
To:
NRC/SECY/RAS
SECY RAS
References
50-271-LR, Entergy-Applicant-E4-16-VY, RAS M-331
Download: ML082530309 (3)


Text

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Subject:

OE17654- Potential Trend for Adverse Equipment Conditions Downstream of Orifices Abstract: Clinton Power Station (CPS) identified a potential trend of issues related to piping orifices that includes component degradation and through-wall leakage.

Reason for Message: The message provides the following results from the Common Cause Analysis:

1. The overall common cause is a lack of knowledge concerning cavitation caused by orifices, the effects cavitation can have on components, and the necessary actions to effectively mitigate cavitation damage.
2. Additionally, the various individual issues fell into two general categories.

a) The first category is physical damage to piping downstream of an orifice that is the result of unaddressed cavitation.

b) The second general category is engineering issues. The first example is original orifices not properly designed. The second example is improperly designed modifications to existing orifices.

The third example is not completely evaluating the impact of increased fluid flow for Extended Power Uprate (EPU) conditions.

Event Date: ............. January 16, 2004 (Various)

Unit Name: .............. Clinton NSSS/A7E: ............... General Electric / Sargent & Lundy Turbine Manufacturer: ... General Electric Maintenance Rule Applicability: No

Description:

Because of the condenser in-leakage identified in piping downstream of an orifice-condenser nozzle, Nuclear Oversight performed a Corrective Action Program review to locate additional piping / orifice related issues at the station. The review identified four (4) additional piping leaks (two (2) in similar locations on the rod drive system).

Additionally, the review identified several other issues where orifice configuration appears to be causing system flw cavitation and/or piping vibration that could contribute to piping degradation.

Causes: The overall common cause is a lack of knowledge concerning cavitation caused by orifices, the effects cavitation can have on components, and the.necessary actions to effectively mitigate cavitation damage.

Corrective Actions:

1. Training will be provided to the engineering population covering orifice design, cavitation resulting in potential component degradation, and mitigation of cavitation concerns,
2. An effectiveness review of the training will be performed to ensure the engineering population understands cavitation and its associated issues. The review will also include a review of recent modifications
  • r U.S. NUCLEAR REGULATORY COMMISSION In the Matter o

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  • V 4. LIc Docket No. *.. *'j2J."Official Exhibit No. JE -- /

OFFERED bJX( DOI iL Intervenor NRC Staft Other IDENTIFIED on"1-3 Witness/Panel i2 ij.

Action Taken: IF~ REJE.CTD WITH MAM

4, that include an orifice design to validate that the design processes includes the Nuclear Engineering Standard (NES-MS-01.2) for Orifice Sizing.

Subject:

OE17654 - Potential Trend for Adverse Equipment Conditions Downstream of Orifices Please note that access to Nuclear Network is restricted to organizations authorized by INPO. The information exchanged via this network is confidential and for the sole use of the authorized organization. Confidentiality is important to ensure the open and frank exchange of information among authorized organizations.

Messages and other information on this web site should not be published,. disclosed, abstracted, or otherwise transferred in any form to any third party, and their contents should not be made public without the prior written consent of INPO.

Information

Contact:

Paul Manbeck Engineer (217) 937-3429 pmanbeck@cps.amergenenergy.com DOCKETED USNRC August 12, 2008 (11:00am)

OFFICE OF SECRETARY RULEMAKINGS AND ADJUDICATIONS STAFF