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| number = ML081090528 | | number = ML081090528 | ||
| issue date = 01/24/2008 | | issue date = 01/24/2008 | ||
| title = | | title = Pilgrim April 2008 Evidentiary Hearing - Intervenor Exhibit 12, Corrosion: NRC Preliminary Notification of Event or Unusual Occurrence, PNO-III-07-021, Both Units at Byron Shut Down Due to Leak in Pipe, October 23, 2007. | ||
| author name = Lochbaum D | | author name = Lochbaum D | ||
| author affiliation = Union of Concerned Scientists | | author affiliation = Union of Concerned Scientists | ||
| Line 16: | Line 16: | ||
=Text= | =Text= | ||
{{#Wiki_filter: | {{#Wiki_filter:US.UCLEAR FEGULATORY COMMWSWO InfaMasd 'ntegy(irim Nuclear Power Stalfloii} | ||
DockINO .50-293-LR W OfFErEDA Sll .. .. -NRICSWII ofth | DockINO .50-293-LR _.Offct*_tWW.N! W DOCKETED IIJSNRr OfFErEDA Sll .. .. - | ||
Uidon of Concerned Scientists +Citizens and Scientists far Environmental Solutions | NRICSWII ofth April 15, 2008 (10:00am) | ||
& AL I-'l | OFFICE OF SECRETARY | ||
The circulating water pumps. located in the building between the concrete cooling towers, moves water from the cooling tower basins through each unit's condenser and then through the cooling towers.Washington Office: 1707 H Street NW Suite 600 *Washlngton DC 20006-3919 a 202-223-6133 o FAX: 202-223-6162 Cambridge Headquarters; Two Statte Square .Cambridge MA 02238-9105 | #omm q-00dbunw Rill FMAKINGS AND AD'JUDICATIONS STAFF UNITED STATES OF AME ..-- '* | ||
* 617-547-5552 | NUCLEAR REGULATORY COMMISSION Before The Atomic Safety And Licensinz Board In the Matter of Docket # 50-293-LR Entergy Corporation Pilgrim Nuclear Power Station License Renewal Application January 24, 2008 DECLARATION OF DAVID LOCHBAUM I, David Lochbaum, prepared the attached reports: "U.S. Nuclear Plants in the 21st Century: The Risk of a Lifetime," (Union Concerned Scientists, May 2004) and Union of Concerned Scientists Issue Brief, "Help Wanted: Dutch Boy at Byron" (Union of Concerned Scientists, October 25, 2007). | ||
-FAX, 617-864-9405 California Office: 2397 ShattuckkAvenue Suite 203 -Berkeley CA 94704-1567 | I stand by the contents of the reports today. | ||
I declare that under penalty of perjury that the foregoing is true and correct. | |||
David tochbaum TFfY:-ý z5r:aý/, | |||
Uidon of Concerned Scientists -2* + | |||
Citizens and Scientists far Environmental Solutions & - * ,.AL I-'l HELP WVANTED: DUTCH BOY AT BYRON On October 19, 2007, operators at the Byron nuclear plant in Illinois began shutting down both reactors after a leak was found in essential service water (ESW) system piping. In event of an accident, the ESW system supplies cooling water to emergency equipment like the emergency diesel generators, the containirnent fan coolers, the component cooling system heat exchangers, and the lube oil and room coolers for the auxiliary leedwater, safety injection, residual heat removal, and charging pumps. In addition, the ESW system provides a source of water for the auxiliary feedwater system pumps. The heat picked up by the .ESW system water in cooling these components is dissipated to the atmosphere via cooling towers. But the cooling towers are not the tall, concrete chimneys making clouds in the aerial photograph of the Byron plant. The ESW cooling towers are the low, I mechanical draft cooling towers in the foreground of the concrete cooling tower on the right The concrete cooling towers remove the waste heat produced by the reactors in making electricity. The circulating water pumps. located in the building between the concrete cooling towers, moves water from the cooling tower basins through each unit's condenser and then through the cooling towers. | |||
Washington Office: 1707 H Street NW Suite 600 *Washlngton DC 20006-3919 a 202-223-6133 o FAX: 202-223-6162 Cambridge Headquarters; Two Statte Square . Cambridge MA 02238-9105 | |||
* 617-547-5552 - FAX, 617-864-9405 California Office: 2397 ShattuckkAvenue Suite 203 - Berkeley CA 94704-1567 | |||
* 510,-43-1872 | * 510,-43-1872 | ||
* FAX; 510-843-3785 October 25, 2007 Page 2 of 3 The ESW piping runs underground from the mechanical dirft cooling towers to the two reactor units and back. The ESW system piping became heavily corroded. | * FAX; 510-843-3785 | ||
As the metal walls of the piping rusted, the water flowing through the piping eroded away some of the rust flakes. This erosion/corrosion process thinned the pipe walls below the minimum acceptable level (0.375 inches) in some places. Workers measured the thickness of some of the pipe walls using ultrasonic devices as little as 0.047 inches. As workers scraped away the rust flakes from the outside surface of the piping, a leak developed. | |||
Because the erosion/corrosion mechanism commonly affected all of the ESW system piping and the condition of the buried portions was uncertain, Exelon conservatively assumed that piping in the ESW systems for both reactors had degraded below the condition needed for the systems to function properly in event of an accident. | October 25, 2007 Page 2 of 3 The ESW piping runs underground from the mechanical dirft cooling towers to the two reactor units and back. The ESW system piping became heavily corroded. As the metal walls of the piping rusted, the water flowing through the piping eroded away some of the rust flakes. This erosion/corrosion process thinned the pipe walls below the minimum acceptable level (0.375 inches) in some places. Workers measured the thickness of some of the pipe walls using ultrasonic devices as little as 0.047 inches. As workers scraped away the rust flakes from the outside surface of the piping, a leak developed. | ||
Consequently, they declared the ESW systems inoperable and had to shut down both reactors as a result. If the ESW system cannot function during an accident, the ability of the plant to avoid a reactor core meltdown with concurrent loss of containment is severely impaired if not entirely prevented. | Because the erosion/corrosion mechanism commonly affected all of the ESW system piping and the condition of the buried portions was uncertain, Exelon conservatively assumed that piping in the ESW systems for both reactors had degraded below the condition needed for the systems to function properly in event of an accident. Consequently, they declared the ESW systems inoperable and had to shut down both reactors as a result. If the ESW system cannot function during an accident, the ability of the plant to avoid a reactor core meltdown with concurrent loss of containment is severely impaired if not entirely prevented. In other words, the accident is likely to become a catastrophe. | ||
In other words, the accident is likely to become a catastrophe. | - The leak occurred as workers scraped rustfrom the heavily corroded ESW pipe. The pipe, which is specified to have a minimuni wall thickness of 0.375 inches, had a nmasured wall thickness of a 047 inches | ||
-The leak occurred as workers scraped | - before rtn removal took that thickness to zero. | ||
The NRC has dispatched a special inspection team to Byron to investigate what happened and why.Prepared by: David Lochbaum Director, Nuclear Safety Project Union of Concerned Scientists October 25, 2007 Page 3 of 3 Additional Photographs of the Corroded ESW System Piping PRELIMINARY NOTIFICATION-REGION III October 23, 2007 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE | The ESW piping runs iunderground and emerges vertically to connect with the cooling tower. The leak occurred just above the concretefloor where the ESW piping emnergesfrom an underground,run. 0 The time needed to correct the problem can not be estimated until workers examine the condition of the entire run of ESW system piping, including the underground portions. The NRC has dispatched a special inspection team to Byron to investigate what happened and why. | ||
-PNO-111-07-012 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. | Prepared by: David Lochbaum Director, Nuclear Safety Project Union of Concerned Scientists | ||
The information is as initially received without verification or evaluation, and is basically all that is known by the Region Ill staff on this date.Facility Licensee Emergency Classification Byron Station Unit 1 and 2 -_ Notification of Unusual Event Exelon Generation Company, LLC __ Alert Byron, Illinois -Site Area Emergency Docket: 50-454/50-455 | |||
-_ General Emergency License: NPF-37/NPF-66 x Not Applicable | October 25, 2007 Page 3 of 3 Additional Photographs of the Corroded ESW System Piping | ||
PRELIMINARY NOTIFICATION- REGION III October 23, 2007 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE - PNO-111-07-012 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region Ill staff on this date. | |||
Facility Licensee Emergency Classification Byron Station Unit 1 and 2 -_ Notification of Unusual Event Exelon Generation Company, LLC __ Alert Byron, Illinois -Site Area Emergency Docket: 50-454/50-455 -_ General Emergency License: NPF-37/NPF-66 x Not Applicable | |||
==SUBJECT:== | ==SUBJECT:== | ||
BOTH UNITS AT BYRON SHUT DOWN DUE TO A LEAK IN PIPE DESCRIPTION: | BOTH UNITS AT BYRON SHUT DOWN DUE TO A LEAK IN PIPE DESCRIPTION: | ||
On October 19, 2007, at 7:55 PMV, Exelon Nuclear Company notified the NRC that operators at the Byron Station began to shut down both reactors due to a leak in an essential service water pipe.The discovery of the leak led to declaring the essential service water system inoperable. | On October 19, 2007, at 7:55 PMV, Exelon Nuclear Company notified the NRC that operators at the Byron Station began to shut down both reactors due to a leak in an essential service water pipe. | ||
According to the plant's Technical Specifications, both reactors had to be shut down.The essential service water system draws water from the river to the cooling basins. Water from the basins would be used to cool important plant safety components required to safely shut down the reactor in an emergency. | The discovery of the leak led to declaring the essential service water system inoperable. | ||
Plant systems performed their functions as designed. | According to the plant's Technical Specifications, both reactors had to be shut down. | ||
The plant was shut down safely and is in a stable shutdown condition. | The essential service water system draws water from the river to the cooling basins. Water from the basins would be used to cool important plant safety components required to safely shut down the reactor in an emergency. | ||
There is no threat to public health and safety.The leak occurred while plant workers were inspecting essential service water system pipes.The inspections were performed to follow up on indications of external corrosion that had been previously identified on all eight similar essential service water pipes.These pipes go from the basins into the ground. Rust was found on sections of piping located between the basins and the ground.The utility is investigating the cause of the leak and evaluating what repairs need to be completed prior to restarting both units.The NRC resident inspectors and region-based inspectors have been monitoring these issues.associated with the essential service water system degradation prior to and since the shutdown.The duration of the dual unit shutdown is expected to exceed 72 hours. There has been media coverage of the issue. | Plant systems performed their functions as designed. The plant was shut down safely and is in a stable shutdown condition. There is no threat to public health and safety. | ||
The State of Illinois has been notified.The information in this preliminary notification is current as of 4:30 p.m. on October 22, 2007.This information has been reviewed with plant management. | The leak occurred while plant workers were inspecting essential service water system pipes. | ||
CONTACTS: Richard Skokowski 630-829-9620 | The inspections were performed to follow up on indications of external corrosion that had been previously identified on all eight similar essential service water pipes. | ||
-PNO-III-07-012A This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. | These pipes go from the basins into the ground. Rust was found on sections of piping located between the basins and the ground. | ||
The information is as initially received without verification or evaluation, and is basically all that is known by the Region III staff on this date.Facility Byron Station Unit 1 and 2 Exelon Generation Company, LLC Byron, Illinois Docket: 50-454/50-455 License: NPF-37/NPF-66 | The utility is investigating the cause of the leak and evaluating what repairs need to be completed prior to restarting both units. | ||
The NRC resident inspectors and region-based inspectors have been monitoring these issues | |||
.associated with the essential service water system degradation prior to and since the shutdown. | |||
The duration of the dual unit shutdown is expected to exceed 72 hours. There has been media coverage of the issue. | |||
The State of Illinois has been notified. | |||
The information in this preliminary notification is current as of 4:30 p.m. on October 22, 2007. | |||
This information has been reviewed with plant management. | |||
CONTACTS: | |||
Richard Skokowski Bruce Bartlett 630-829-9620 815-234-5451 | |||
PRELIMINARY NOTIFICATION- REGION III October 31, 2007 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE - PNO-III-07-012A This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region III staff on this date. | |||
Facility Licensee Emergency Classification Byron Station Unit 1 and 2 Notification of Unusual Event Exelon Generation Company, LLC Alert Byron, Illinois Site Area Emergency Docket: 50-454/50-455 General Emergency License: NPF-37/NPF-66 x Not Applicable | |||
==SUBJECT:== | ==SUBJECT:== | ||
UPDATE TO DUAL UNIT SHUTDOWN DESCRIPTION: | UPDATE TO DUAL UNIT SHUTDOWN DESCRIPTION: | ||
This preliminary notification supplements information in PNO-111-07-012, which documented the shutdown of the Byron Station Unit 1 and Unit 2 reactors on October 19, 2007, due to a leak in an essential service water pipe.During the shutdown, the utility investigated the cause of the leak and made necessary repairs in the essential service water system to support start-up. | This preliminary notification supplements information in PNO-111-07-012, which documented the shutdown of the Byron Station Unit 1 and Unit 2 reactors on October 19, 2007, due to a leak in an essential service water pipe. | ||
Additional repairs are in progress.Byron Unit 1 and Unit 2 restarted on October 30, 2007. Full power is expected to be achieved on or about November 2, 2007.The NRC had dispatched a Special Inspection team to the plant to review the root causes of the problem, extent of condition, and corrective actions. The team continues the review of the issues associated with the essential service water system. Prior to the reactor restart, the team verified the adequacy of the licensee's repairs to the essential service water system that had necessitated the shutdown.This information is current as of 7:30 a.m. on October 31, 2007.The information in this preliminary notification has been reviewed with licensee management. | During the shutdown, the utility investigated the cause of the leak and made necessary repairs in the essential service water system to support start-up. Additional repairs are in progress. | ||
Richard Skokowski 630-829-9620 | Byron Unit 1 and Unit 2 restarted on October 30, 2007. Full power is expected to be achieved on or about November 2, 2007. | ||
The information is as initially received without verification or evaluation, and is basically all that is known by Region II staff (Atlanta, Georgia) on this date.Facility Licensee Emergency Classification Catawba Nuclear Station Notification of Unusual Event Units 1 & 2 Alert York, SC Site Area Emergency Dockets/License: | The NRC had dispatched a Special Inspection team to the plant to review the root causes of the problem, extent of condition, and corrective actions. The team continues the review of the issues associated with the essential service water system. Prior to the reactor restart, the team verified the adequacy of the licensee's repairs to the essential service water system that had necessitated the shutdown. | ||
50-413, 50-414 General Emergency X Not Applicable | This information is current as of 7:30 a.m. on October 31, 2007. | ||
The information in this preliminary notification has been reviewed with licensee management. | |||
Richard Skokowski Bruce Bartlett 630-829-9620 815-234-5451 | |||
October 11, 2007 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-11-07-012 This preliminary notification constitutes EARLY notice of events of possible safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by Region II staff (Atlanta, Georgia) on this date. | |||
Facility Licensee Emergency Classification Catawba Nuclear Station Notification of Unusual Event Units 1 & 2 Alert York, SC Site Area Emergency Dockets/License: 50-413, 50-414 General Emergency X Not Applicable | |||
==SUBJECT:== | ==SUBJECT:== | ||
ONSITE GROUND WATER TRITIUM CONTAMINATION On October 8, 2007, plant staff at the Catawba Nuclear Station received sample results which indicated the presence of detectable concentrations of tritium (hydrogen-3) in liquids collected from a ground water monitoring well located within the owner controlled area (OCA). The monitoring well is located approximately one half mile inside the property boundary of the facility. | ONSITE GROUND WATER TRITIUM CONTAMINATION On October 8, 2007, plant staff at the Catawba Nuclear Station received sample results which indicated the presence of detectable concentrations of tritium (hydrogen-3) in liquids collected from a ground water monitoring well located within the owner controlled area (OCA). The monitoring well is located approximately one half mile inside the property boundary of the facility. The measured level of activity in the sample obtained from this monitoring well was approximately 42,000 pCi/L from a depth of 50 feet. Additional water samples collected from other monitoring well locations onsite within the OCA also had measurable concentrations of tritium with a maximum level of approximately 4,000 pCi/L. This was the initial sampling of 30 new ground water monitoring wells which were recently installed at Catawba Nuclear Station in support of the Nuclear Energy Institute (NEI) ground water initiative. | ||
The measured level of activity in the sample obtained from this monitoring well was approximately 42,000 pCi/L from a depth of 50 feet. Additional water samples collected from other monitoring well locations onsite within the OCA also had measurable concentrations of tritium with a maximum level of approximately 4,000 pCi/L. This was the initial sampling of 30 new ground water monitoring wells which were recently installed at Catawba Nuclear Station in support of the Nuclear Energy Institute (NEI) ground water initiative. | The licensee has begun implementation of an action plan to monitor and evaluate the extent and potential for movement of detectable tritium in the groundwater based on the tritium detected in the single monitoring well which produced the sample with elevated levels of tritium. | ||
The licensee has begun implementation of an action plan to monitor and evaluate the extent and potential for movement of detectable tritium in the groundwater based on the tritium detected in the single monitoring well which produced the sample with elevated levels of tritium.This includes taking additional samples from the 35 ground water monitoring wells located within the OCA and analyzing them for tritium and other radionuclides. | This includes taking additional samples from the 35 ground water monitoring wells located within the OCA and analyzing them for tritium and other radionuclides. | ||
Once the licensee determined that tritium levels in excess of the NEI voluntary reporting criteria (greater than 20,000 pCi/L for onsite groundwater) were confirmed to be present in one of the ground water monitoring wells installed onsite, a 10 CFR 50.72 (EN 43703) report was submitted on October 9, 2007, at 9:41 a.m., with this information. | Once the licensee determined that tritium levels in excess of the NEI voluntary reporting criteria (greater than 20,000 pCi/L for onsite groundwater) were confirmed to be present in one of the ground water monitoring wells installed onsite, a 10 CFR 50.72 (EN 43703) report was submitted on October 9, 2007, at 9:41 a.m., with this information. | ||
The South Carolina Department of Health and Environmental Control visited the Catawba Nuclear Station site on October 10, 2007, and collected water samples from the only two drinking water wells within the OCA. A split sample from each well was provided to Catawba personnel for confirmatory testing. The site does not use wells to supply potable water for employees at the facility.Region II continues to monitor and assess the licensee's actions in response to this issue.South Carolina Department of Health and Environmental Control (SCDHEC) intends to return to Catawba Nuclear Station on October 12, 2007, to begin sampling public and private drinking water wells in the surrounding area. The licensee will receive split samples from any well that is sampled by SCDHEC.The SCDHEC Division of Media Relations has issued a news release on this issue dated October 10, 2007. News coverage has been provided by both newspaper and television outlets in North Carolina and South Carolina starting on October 10, 2007.Additional information on groundwater contamination from tritium can be found at the NRC public web site at the following address: http/i!wtww.nrc.gov/reactors/operatingiops-experience/grndv.Ar-contamn-tritium.html Region II received initial notification of ground water tritium contamination on October 8, 2007, when licensee management informed the Senior Resident Inspector. | The South Carolina Department of Health and Environmental Control visited the Catawba Nuclear Station site on October 10, 2007, and collected water samples from the only two drinking water wells within the OCA. A split sample from each well was provided to Catawba personnel for confirmatory testing. The site does not use wells to supply potable water for employees at the facility. | ||
The information presented herein has been discussed with the licensee and the State, and is current as of 12:00 p.m., on October 11, 2007.The state of South Carolina Department of Health and Environmental Control has been notified.CONTACTS: | Region II continues to monitor and assess the licensee's actions in response to this issue. | ||
James H. Moorman George B. Kuzo Brian R. Bonser (404) 562-4647 (404) 562-4658 (404) 562-4653}} | South Carolina Department of Health and Environmental Control (SCDHEC) intends to return to Catawba Nuclear Station on October 12, 2007, to begin sampling public and private drinking | ||
water wells in the surrounding area. The licensee will receive split samples from any well that is sampled by SCDHEC. | |||
The SCDHEC Division of Media Relations has issued a news release on this issue dated October 10, 2007. News coverage has been provided by both newspaper and television outlets in North Carolina and South Carolina starting on October 10, 2007. | |||
Additional information on groundwater contamination from tritium can be found at the NRC public web site at the following address: http/i!wtww.nrc.gov/reactors/operatingiops-experience/grndv.Ar-contamn-tritium.html Region II received initial notification of ground water tritium contamination on October 8, 2007, when licensee management informed the Senior Resident Inspector. The information presented herein has been discussed with the licensee and the State, and is current as of 12:00 p.m., on October 11, 2007. | |||
The state of South Carolina Department of Health and Environmental Control has been notified. | |||
CONTACTS: James H. Moorman George B. Kuzo Brian R. Bonser (404) 562-4647 (404) 562-4658 (404) 562-4653}} | |||
Latest revision as of 08:16, 7 December 2019
| ML081090528 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 01/24/2008 |
| From: | Lochbaum D Union of Concerned Scientists |
| To: | Atomic Safety and Licensing Board Panel |
| SECY RAS | |
| References | |
| 50-293-LR, ASLBP 06-848-02-LR, Pilgrim-Intervenor-25, RAS J-55 | |
| Download: ML081090528 (9) | |
Text
US.UCLEAR FEGULATORY COMMWSWO InfaMasd 'ntegy(irim Nuclear Power Stalfloii}
DockINO .50-293-LR _.Offct*_tWW.N! W DOCKETED IIJSNRr OfFErEDA Sll .. .. -
NRICSWII ofth April 15, 2008 (10:00am)
OFFICE OF SECRETARY
- omm q-00dbunw Rill FMAKINGS AND AD'JUDICATIONS STAFF UNITED STATES OF AME ..-- '*
NUCLEAR REGULATORY COMMISSION Before The Atomic Safety And Licensinz Board In the Matter of Docket # 50-293-LR Entergy Corporation Pilgrim Nuclear Power Station License Renewal Application January 24, 2008 DECLARATION OF DAVID LOCHBAUM I, David Lochbaum, prepared the attached reports: "U.S. Nuclear Plants in the 21st Century: The Risk of a Lifetime," (Union Concerned Scientists, May 2004) and Union of Concerned Scientists Issue Brief, "Help Wanted: Dutch Boy at Byron" (Union of Concerned Scientists, October 25, 2007).
I stand by the contents of the reports today.
I declare that under penalty of perjury that the foregoing is true and correct.
David tochbaum TFfY:-ý z5r:aý/,
Uidon of Concerned Scientists -2* +
Citizens and Scientists far Environmental Solutions & - * ,.AL I-'l HELP WVANTED: DUTCH BOY AT BYRON On October 19, 2007, operators at the Byron nuclear plant in Illinois began shutting down both reactors after a leak was found in essential service water (ESW) system piping. In event of an accident, the ESW system supplies cooling water to emergency equipment like the emergency diesel generators, the containirnent fan coolers, the component cooling system heat exchangers, and the lube oil and room coolers for the auxiliary leedwater, safety injection, residual heat removal, and charging pumps. In addition, the ESW system provides a source of water for the auxiliary feedwater system pumps. The heat picked up by the .ESW system water in cooling these components is dissipated to the atmosphere via cooling towers. But the cooling towers are not the tall, concrete chimneys making clouds in the aerial photograph of the Byron plant. The ESW cooling towers are the low, I mechanical draft cooling towers in the foreground of the concrete cooling tower on the right The concrete cooling towers remove the waste heat produced by the reactors in making electricity. The circulating water pumps. located in the building between the concrete cooling towers, moves water from the cooling tower basins through each unit's condenser and then through the cooling towers.
Washington Office: 1707 H Street NW Suite 600 *Washlngton DC 20006-3919 a 202-223-6133 o FAX: 202-223-6162 Cambridge Headquarters; Two Statte Square . Cambridge MA 02238-9105
- 617-547-5552 - FAX, 617-864-9405 California Office: 2397 ShattuckkAvenue Suite 203 - Berkeley CA 94704-1567
- 510,-43-1872
- FAX; 510-843-3785
October 25, 2007 Page 2 of 3 The ESW piping runs underground from the mechanical dirft cooling towers to the two reactor units and back. The ESW system piping became heavily corroded. As the metal walls of the piping rusted, the water flowing through the piping eroded away some of the rust flakes. This erosion/corrosion process thinned the pipe walls below the minimum acceptable level (0.375 inches) in some places. Workers measured the thickness of some of the pipe walls using ultrasonic devices as little as 0.047 inches. As workers scraped away the rust flakes from the outside surface of the piping, a leak developed.
Because the erosion/corrosion mechanism commonly affected all of the ESW system piping and the condition of the buried portions was uncertain, Exelon conservatively assumed that piping in the ESW systems for both reactors had degraded below the condition needed for the systems to function properly in event of an accident. Consequently, they declared the ESW systems inoperable and had to shut down both reactors as a result. If the ESW system cannot function during an accident, the ability of the plant to avoid a reactor core meltdown with concurrent loss of containment is severely impaired if not entirely prevented. In other words, the accident is likely to become a catastrophe.
- The leak occurred as workers scraped rustfrom the heavily corroded ESW pipe. The pipe, which is specified to have a minimuni wall thickness of 0.375 inches, had a nmasured wall thickness of a 047 inches
- before rtn removal took that thickness to zero.
The ESW piping runs iunderground and emerges vertically to connect with the cooling tower. The leak occurred just above the concretefloor where the ESW piping emnergesfrom an underground,run. 0 The time needed to correct the problem can not be estimated until workers examine the condition of the entire run of ESW system piping, including the underground portions. The NRC has dispatched a special inspection team to Byron to investigate what happened and why.
Prepared by: David Lochbaum Director, Nuclear Safety Project Union of Concerned Scientists
October 25, 2007 Page 3 of 3 Additional Photographs of the Corroded ESW System Piping
PRELIMINARY NOTIFICATION- REGION III October 23, 2007 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE - PNO-111-07-012 This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region Ill staff on this date.
Facility Licensee Emergency Classification Byron Station Unit 1 and 2 -_ Notification of Unusual Event Exelon Generation Company, LLC __ Alert Byron, Illinois -Site Area Emergency Docket: 50-454/50-455 -_ General Emergency License: NPF-37/NPF-66 x Not Applicable
SUBJECT:
BOTH UNITS AT BYRON SHUT DOWN DUE TO A LEAK IN PIPE DESCRIPTION:
On October 19, 2007, at 7:55 PMV, Exelon Nuclear Company notified the NRC that operators at the Byron Station began to shut down both reactors due to a leak in an essential service water pipe.
The discovery of the leak led to declaring the essential service water system inoperable.
According to the plant's Technical Specifications, both reactors had to be shut down.
The essential service water system draws water from the river to the cooling basins. Water from the basins would be used to cool important plant safety components required to safely shut down the reactor in an emergency.
Plant systems performed their functions as designed. The plant was shut down safely and is in a stable shutdown condition. There is no threat to public health and safety.
The leak occurred while plant workers were inspecting essential service water system pipes.
The inspections were performed to follow up on indications of external corrosion that had been previously identified on all eight similar essential service water pipes.
These pipes go from the basins into the ground. Rust was found on sections of piping located between the basins and the ground.
The utility is investigating the cause of the leak and evaluating what repairs need to be completed prior to restarting both units.
The NRC resident inspectors and region-based inspectors have been monitoring these issues
.associated with the essential service water system degradation prior to and since the shutdown.
The duration of the dual unit shutdown is expected to exceed 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. There has been media coverage of the issue.
The State of Illinois has been notified.
The information in this preliminary notification is current as of 4:30 p.m. on October 22, 2007.
This information has been reviewed with plant management.
CONTACTS:
Richard Skokowski Bruce Bartlett 630-829-9620 815-234-5451
PRELIMINARY NOTIFICATION- REGION III October 31, 2007 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE - PNO-III-07-012A This preliminary notification constitutes EARLY notice of events of POSSIBLE safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by the Region III staff on this date.
Facility Licensee Emergency Classification Byron Station Unit 1 and 2 Notification of Unusual Event Exelon Generation Company, LLC Alert Byron, Illinois Site Area Emergency Docket: 50-454/50-455 General Emergency License: NPF-37/NPF-66 x Not Applicable
SUBJECT:
UPDATE TO DUAL UNIT SHUTDOWN DESCRIPTION:
This preliminary notification supplements information in PNO-111-07-012, which documented the shutdown of the Byron Station Unit 1 and Unit 2 reactors on October 19, 2007, due to a leak in an essential service water pipe.
During the shutdown, the utility investigated the cause of the leak and made necessary repairs in the essential service water system to support start-up. Additional repairs are in progress.
Byron Unit 1 and Unit 2 restarted on October 30, 2007. Full power is expected to be achieved on or about November 2, 2007.
The NRC had dispatched a Special Inspection team to the plant to review the root causes of the problem, extent of condition, and corrective actions. The team continues the review of the issues associated with the essential service water system. Prior to the reactor restart, the team verified the adequacy of the licensee's repairs to the essential service water system that had necessitated the shutdown.
This information is current as of 7:30 a.m. on October 31, 2007.
The information in this preliminary notification has been reviewed with licensee management.
Richard Skokowski Bruce Bartlett 630-829-9620 815-234-5451
October 11, 2007 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE PNO-11-07-012 This preliminary notification constitutes EARLY notice of events of possible safety or public interest significance. The information is as initially received without verification or evaluation, and is basically all that is known by Region II staff (Atlanta, Georgia) on this date.
Facility Licensee Emergency Classification Catawba Nuclear Station Notification of Unusual Event Units 1 & 2 Alert York, SC Site Area Emergency Dockets/License: 50-413, 50-414 General Emergency X Not Applicable
SUBJECT:
ONSITE GROUND WATER TRITIUM CONTAMINATION On October 8, 2007, plant staff at the Catawba Nuclear Station received sample results which indicated the presence of detectable concentrations of tritium (hydrogen-3) in liquids collected from a ground water monitoring well located within the owner controlled area (OCA). The monitoring well is located approximately one half mile inside the property boundary of the facility. The measured level of activity in the sample obtained from this monitoring well was approximately 42,000 pCi/L from a depth of 50 feet. Additional water samples collected from other monitoring well locations onsite within the OCA also had measurable concentrations of tritium with a maximum level of approximately 4,000 pCi/L. This was the initial sampling of 30 new ground water monitoring wells which were recently installed at Catawba Nuclear Station in support of the Nuclear Energy Institute (NEI) ground water initiative.
The licensee has begun implementation of an action plan to monitor and evaluate the extent and potential for movement of detectable tritium in the groundwater based on the tritium detected in the single monitoring well which produced the sample with elevated levels of tritium.
This includes taking additional samples from the 35 ground water monitoring wells located within the OCA and analyzing them for tritium and other radionuclides.
Once the licensee determined that tritium levels in excess of the NEI voluntary reporting criteria (greater than 20,000 pCi/L for onsite groundwater) were confirmed to be present in one of the ground water monitoring wells installed onsite, a 10 CFR 50.72 (EN 43703) report was submitted on October 9, 2007, at 9:41 a.m., with this information.
The South Carolina Department of Health and Environmental Control visited the Catawba Nuclear Station site on October 10, 2007, and collected water samples from the only two drinking water wells within the OCA. A split sample from each well was provided to Catawba personnel for confirmatory testing. The site does not use wells to supply potable water for employees at the facility.
Region II continues to monitor and assess the licensee's actions in response to this issue.
South Carolina Department of Health and Environmental Control (SCDHEC) intends to return to Catawba Nuclear Station on October 12, 2007, to begin sampling public and private drinking
water wells in the surrounding area. The licensee will receive split samples from any well that is sampled by SCDHEC.
The SCDHEC Division of Media Relations has issued a news release on this issue dated October 10, 2007. News coverage has been provided by both newspaper and television outlets in North Carolina and South Carolina starting on October 10, 2007.
Additional information on groundwater contamination from tritium can be found at the NRC public web site at the following address: http/i!wtww.nrc.gov/reactors/operatingiops-experience/grndv.Ar-contamn-tritium.html Region II received initial notification of ground water tritium contamination on October 8, 2007, when licensee management informed the Senior Resident Inspector. The information presented herein has been discussed with the licensee and the State, and is current as of 12:00 p.m., on October 11, 2007.
The state of South Carolina Department of Health and Environmental Control has been notified.
CONTACTS: James H. Moorman George B. Kuzo Brian R. Bonser (404) 562-4647 (404) 562-4658 (404) 562-4653