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| number = ML082530470 | | number = ML082530470 | ||
| issue date = 07/23/2008 | | issue date = 07/23/2008 | ||
| title = | | title = Vermont Yankee July 2008 Evidentiary Hearing - Applicant Exhibit E4-14-VY, INPO Report OE-18478 (Clinton) | ||
| author name = | | author name = | ||
| author affiliation = Entergy Nuclear Operations, Inc, Entergy Nuclear Vermont Yankee, LLC | | author affiliation = Entergy Nuclear Operations, Inc, Entergy Nuclear Vermont Yankee, LLC | ||
| Line 19: | Line 19: | ||
==Subject:== | ==Subject:== | ||
OE18478 -Update to OE 17412 Pipe Damage Found to, Cause High Condenser Air In-leakage Abstract: | OE18478 - Update to OE 17412 Pipe Damage Found to, Cause High Condenser Air In-leakage Abstract: This is an update to OE17412 Clinton Power Station (CPS) submitted in November 2003. CPS took a down power to 49% reactor power on October 31, 2003 to perform field investigations to locate the source of high main condenser air in-leakage. CPS discovered that the continuous vent lines for both #2 feedwater heaters were leaking. | ||
This is an update to OE17412 Clinton Power Station (CPS)submitted in November 2003. CPS took a down power to 49% reactor power on October 31, 2003 to perform field investigations to locate the source of high main condenser air in-leakage. | During ClR09, CPS removed the leaking piping and installed CrMo material replacement piping. CPS evaluated the damaged piping and determined that the cause of the through-wall holes was impingement. | ||
CPS discovered that the continuous vent lines for both #2 feedwater heaters were leaking.During ClR09, CPS removed the leaking piping and installed CrMo material replacement piping. CPS evaluated the damaged piping and determined that the cause of the through-wall holes was impingement. | Reason for Message: Communicate final evaluation results for the cause of a large condenser air in-leakage. | ||
Reason for Message: Communicate final evaluation results for the cause of a large condenser air in-leakage. | Event Date: ............. 10-31-03 Unit Name: ...............Clinton NSSS/A-E: ................ General Electric / Sargent & Lundy Turbine Manufacturer: ... General Electric Maintenance Rule Applicability: No | ||
Event Date: ............. | |||
10-31-03 Unit Name: ............... | |||
Clinton NSSS/A-E: | |||
................ | |||
General Electric / Sargent & Lundy Turbine Manufacturer: | |||
... General Electric Maintenance Rule Applicability: | |||
No | |||
== Description:== | == | ||
Description:== | |||
The Drains and Vents (DV) system consists of piping that serves as the drainage path for excess heating steam (extraction steam (ES)) and water from the shell side of the FW heaters to either drain tanks or the condenser. Those portions of DV lines that connect to the condenser operate at a vacuum near the condenser. If a DV line experiences a through wall hole near the condenser, air in-leakage to the condenser will occur. | |||
lDV07AA and AB are continuous flow DV lines that connect to the condenser. These lines connect the 2A and 2B FW heaters to the condenser. The piping geometry consists of a straight run of pipe connecting to a 45-degree elbow, then a short run (6-12 inches) of straight pipe connected to a second-45-degree elbow. Finally, a straight run of pipe (1-2 feet) connects the second 45-degree elbow to the condenser nozzle. Each of the welds had a backing ring attached. | |||
Both of these lines had holes located on the extrados of the second 45-degree elbow. These holes allowed air in-leakage to the condenser. | |||
Causes: The degradation mechanism that caused these holes is steam DOCKETED jet impingement. Impingement is a localized mechanical degradation USNRC mechanism and is similar to sandblasting the surface., The small watekgust12,20080(1:Oam) droplets in the steam/moisture mixture impact the surface removing very small amounts of material. Over time, the result is a hole, OFFICE OF SECRETARY RULEMAKINGS AND through the component wall. ADJUDICATIONS STAFF The impingement occurred because of the piping geometry; i.e. the back-to-back 45-degree elbows, and their close proximity to the .. | |||
condenser. The inclusion of the backing rings during construction. ,. | |||
magnified the impingement. | |||
There is also some evidence of flow-accelerated corrosion (FAC),, <-. | |||
however FAC did not cause the holes. FAC is a chemical degradation, | |||
U.S. NUCLEAR REGULATORY COMMISSION Inthe Matter of E 1N4J* | |||
1 MeJye,i "Y4. t LIZ. | |||
Docket No. , Official Exhibit No. | |||
OFFERED by plicant/L4n Intervenor_ | |||
NRtAff Other IDETIMFIED &tlzsios Witness/Panel .W$.. | |||
AoTe: mArjE REJECTED WITHDRAWN RepwW/Clerk 8L*-- | |||
mechanism. Under the right conditions, i'e. temperature, pH, flow velocity, oxygen content, and moisture content for two-phase flow,' the protective corrosion layer on the interior surface dissolves and washes away. The material then reforms the passive corrosion layer, causing wall thinning. This process continually repeats itself until there is significant wall loss. FAC covers larger sections of a component than impingement. | |||
Corrective-Actions: Action 1, identify the component scope for impingement inspection program. The systems of concern are DV, TD, ES, and HD. -Closure of this assignment includes documentation of the results and providing the results to the FAC Program owner. | |||
Action 2, developand implement inspection program'.using scope from Action 1. | |||
NRtAff Other IDETIMFIED | |||
&tlzsios Witness/Panel .W$..AoTe: mArjE REJECTED WITHDRAWN RepwW/Clerk - | |||
mechanism. | |||
Under the right conditions, i'e. temperature, pH, flow velocity, oxygen content, and moisture content for two-phase flow,' the protective corrosion layer on the interior surface dissolves and washes away. The material then reforms the passive corrosion layer, causing wall thinning. | |||
This process continually repeats itself until there is significant wall loss. FAC covers larger sections of a component than impingement. | |||
Corrective-Actions: | |||
Action 1, identify the component scope for impingement inspection program. The systems of concern are DV, TD, ES, and HD. -Closure of this assignment includes documentation of the results and providing the results to the FAC Program owner.Action 2, developand implement inspection program'.using scope from Action 1. | |||
==Subject:== | ==Subject:== | ||
0E18478"- | 0E18478"- Update to OE 17412 Pipe Damage Found to Cause High Condenser Air In-leakage 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. | ||
Update to OE 17412 Pipe Damage Found to Cause High Condenser Air In-leakage 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. | 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. | ||
Confidentiality is important to, ensure the open and frank exchange of information among authorized organizations. | Information | ||
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 FAC Program Owner 217 937-3429 pmanbeck@cps.amergenenergy.com 191ýRý Dý ýN | ==Contact:== | ||
Paul Manbeck FAC Program Owner 217 937-3429 pmanbeck@cps.amergenenergy.com 191ýRý Dý ýN ý *}} | |||
Latest revision as of 05:56, 7 December 2019
| ML082530470 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee, Clinton  |
| Issue date: | 07/23/2008 |
| From: | Entergy Nuclear Operations, Entergy Nuclear Vermont Yankee |
| To: | NRC/SECY/RAS |
| SECY RAS | |
| References | |
| 06-849-03-LR, 50-271-LR, Entergy-Applicant-E4-14-VY, RAS M-329 | |
| Download: ML082530470 (3) | |
Text
Subject:
OE18478 - Update to OE 17412 Pipe Damage Found to, Cause High Condenser Air In-leakage Abstract: This is an update to OE17412 Clinton Power Station (CPS) submitted in November 2003. CPS took a down power to 49% reactor power on October 31, 2003 to perform field investigations to locate the source of high main condenser air in-leakage. CPS discovered that the continuous vent lines for both #2 feedwater heaters were leaking.
During ClR09, CPS removed the leaking piping and installed CrMo material replacement piping. CPS evaluated the damaged piping and determined that the cause of the through-wall holes was impingement.
Reason for Message: Communicate final evaluation results for the cause of a large condenser air in-leakage.
Event Date: ............. 10-31-03 Unit Name: ...............Clinton NSSS/A-E: ................ General Electric / Sargent & Lundy Turbine Manufacturer: ... General Electric Maintenance Rule Applicability: No
==
Description:==
The Drains and Vents (DV) system consists of piping that serves as the drainage path for excess heating steam (extraction steam (ES)) and water from the shell side of the FW heaters to either drain tanks or the condenser. Those portions of DV lines that connect to the condenser operate at a vacuum near the condenser. If a DV line experiences a through wall hole near the condenser, air in-leakage to the condenser will occur.
lDV07AA and AB are continuous flow DV lines that connect to the condenser. These lines connect the 2A and 2B FW heaters to the condenser. The piping geometry consists of a straight run of pipe connecting to a 45-degree elbow, then a short run (6-12 inches) of straight pipe connected to a second-45-degree elbow. Finally, a straight run of pipe (1-2 feet) connects the second 45-degree elbow to the condenser nozzle. Each of the welds had a backing ring attached.
Both of these lines had holes located on the extrados of the second 45-degree elbow. These holes allowed air in-leakage to the condenser.
Causes: The degradation mechanism that caused these holes is steam DOCKETED jet impingement. Impingement is a localized mechanical degradation USNRC mechanism and is similar to sandblasting the surface., The small watekgust12,20080(1:Oam) droplets in the steam/moisture mixture impact the surface removing very small amounts of material. Over time, the result is a hole, OFFICE OF SECRETARY RULEMAKINGS AND through the component wall. ADJUDICATIONS STAFF The impingement occurred because of the piping geometry; i.e. the back-to-back 45-degree elbows, and their close proximity to the ..
condenser. The inclusion of the backing rings during construction. ,.
magnified the impingement.
There is also some evidence of flow-accelerated corrosion (FAC),, <-.
however FAC did not cause the holes. FAC is a chemical degradation,
U.S. NUCLEAR REGULATORY COMMISSION Inthe Matter of E 1N4J*
1 MeJye,i "Y4. t LIZ.
Docket No. , Official Exhibit No.
OFFERED by plicant/L4n Intervenor_
NRtAff Other IDETIMFIED &tlzsios Witness/Panel .W$..
AoTe: mArjE REJECTED WITHDRAWN RepwW/Clerk 8L*--
mechanism. Under the right conditions, i'e. temperature, pH, flow velocity, oxygen content, and moisture content for two-phase flow,' the protective corrosion layer on the interior surface dissolves and washes away. The material then reforms the passive corrosion layer, causing wall thinning. This process continually repeats itself until there is significant wall loss. FAC covers larger sections of a component than impingement.
Corrective-Actions: Action 1, identify the component scope for impingement inspection program. The systems of concern are DV, TD, ES, and HD. -Closure of this assignment includes documentation of the results and providing the results to the FAC Program owner.
Action 2, developand implement inspection program'.using scope from Action 1.
Subject:
0E18478"- Update to OE 17412 Pipe Damage Found to Cause High Condenser Air In-leakage 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 FAC Program Owner 217 937-3429 pmanbeck@cps.amergenenergy.com 191ýRý Dý ýN ý *