BYRON 2003-0114, Sixty-Day Response to NRC Bulleting 2003-02, Leakage from Reactor Pressure Vessel Lower Head Penetrations and Reactor Coolant Pressure Boundary Integrity.
| ML033510558 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 12/12/2003 |
| From: | Kuczynski S Exelon Generation Co, Exelon Nuclear |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 1.10.0101, BL-03-002, BYRON 2003-0114 | |
| Download: ML033510558 (5) | |
Text
Exelkn.
Exelon Generation Company, LLC www.exeloncorp.com Nuclear Byron Station 4450 North German Church Road Byron, IL 61010-9794 December 12, 2003 LTR: BYRON 2003-0114 File: 1.10.0101 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852 Byron Station Unit 1 Facility Operating License No. NPF-37 NRC Docket No. STN 50-454
Subject:
Byron Station Unit 1 Sixty-Day Response to NRC Bulletin 2003-02, "Leakage from Reactor Pressure Vessel Lower Head Penetrations and Reactor Coolant Pressure Boundary Integrity" On August 21, 2003, the NRC issued NRC Bulletin 2003-02, "Leakage from Reactor Pressure Vessel Lower Head Penetrations and Reactor Coolant Pressure Boundary Integrity." This bulletin requires the following information be submitted to the NRC within 60 days after plant restart following the next inspection of the reactor pressure vessel lower head penetrations:
"a summary of the inspections performed, the extent of the inspections, the methods used, a description of the as-found condition of the lower head, any findings of relevant indications of through-wall leakage, and a summary of the disposition of any findings of boric acid deposits and any corrective actions taken as a result of indications found."
Pursuant to 10 CFR 50.54, "Conditions of licenses," paragraph (f), Attachment I to this letter provides the Byron Station, Unit 1 60-day response. This response is due to the NRC by December 15, 2003.
.\0 09
December 12, 2003 U.S. Nuclear Regulatory Commission Page 2 Should you have any questions or desire additional information regarding this letter, please contact William Grundmann, Regulatory Assurance Manager, at (815) 406-2800.
I declare under penalty of perjury that the foregoing is true and correct.
Respectfully, Executed on ______ / °__3___
Stephen E. Kuczynski Site Vice President Byron Nuclear Generating Station
Enclosures:
Attachment 1, Byron Station Unit 1 Sixty-Day Response to NRC Bulletin 2003-02 cc: Regional Administrator - NRC Region III NRC Senior Resident Inspector - Byron Station
ATTACHMENT I Byron Station Unit I Sixty-Day Response to NRC Bulletin 2003-02 "Leakage from Reactor Pressure Vessel Lower Head Penetrations and Reactor Coolant Pressure Boundary Integrity"
Attachment I Byron Station Unit I Sixty-Day Response to NRC Bulletin 2003-02 On August 21, 2003, the NRC issued NRC Bulletin 2003-02, "Leakage from Reactor Pressure Vessel Lower Head Penetrations and Reactor Coolant Pressure Boundary Integrity." This bulletin requires the following information be submitted to the NRC within 60 days of plant restart following the next inspection of the reactor pressure vessel (RPV) lower head penetrations:
Within 60 days of plant restartfollowing the next inspection of the RPV lower head penetrations, the subject PWR addresseesshould submit to the NRC a summary of the inspectionsperformed, the extent of the inspections, the methods used, a description of the as-found condition of the lower head, any findings of relevant indications of through-wallleakage, and a summary of the disposition of any findings of boric acid deposits and any corrective actions taken as a result of indicationsfound.
Response
Summary of the Inspections Performed, Extent of the Inspections, and Methods Used A remote visual inspection of the Unit 1 RPV bottom mounted instrumentation (BMI) nozzles (58 total) and RPV lower head was performed in Mode 5 descending during Byron Unit 1 refueling outage 12 (B1 R1 2) in Fall 2003. The inspection, performed by VT-2 qualified personnel, examined the full circumference around each BMI nozzle on the RPV lower head using multiple passes (i.e., four total) to ensure full coverage with overlap. The inspection was performed in accordance with procedure ER-AP-335-1012, 'Visual Examination of PWR Reactor Vessel Head Penetrations." The inspection used remote equipment capable of resolving the appropriate detail (i.e., VT-1/1C character height in accordance with 1992 ASME Boiler and Pressure Vessel Code Section Xl, Table IWA-2210-1) at two feet. The actual distances viewed were less than two feet which gave extremely close views of the BMI nozzle to RPV lower head interface region, thereby ensuring any boric acid leakage would be easily identified.
Description of the As-Found Condition, Findings of Relevant Indications, and Summary of the Disposition of any Findings The RPV lower head visual inspection identified no evidence of any boric acid deposits in the BMI nozzle to RPV lower head interface region. However, it was apparent the reactor cavity boot seals had leaked borated water down the side of the RPV during previous refueling outages. This was documented in the corrective action program. The RPV lower head also had a minor layer of surface corrosion with no discernable thickness that in many locations had become flaky and was easily removed with little effort. These findings were found to be acceptable as no RPV boric acid leakage was identified and no wastage was observed.
Page 1 of 2
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Attachment I Corrective Actions Taken There were no corrective actions taken as a result of indications found as no evidence of RPV boric acid leakage was identified. The RPV lower head and the BMI nozzle to RPV lower head interface regions were cleaned using a low-pressure (approximately 1200 psi) plain water power wash. The low-pressure wash removed the lightly adhered, flaky rust material and boron residue from the cavity boot seal leak and left the normal surface oxidation layer intact. This was done to ensure a crisp demarcation between the BMI nozzle and the RPV lower head for future inspections.
Page 2 of 2
Text
Exelkn.
Exelon Generation Company, LLC www.exeloncorp.com Nuclear Byron Station 4450 North German Church Road Byron, IL 61010-9794 December 12, 2003 LTR: BYRON 2003-0114 File: 1.10.0101 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 11555 Rockville Pike Rockville, MD 20852 Byron Station Unit 1 Facility Operating License No. NPF-37 NRC Docket No. STN 50-454
Subject:
Byron Station Unit 1 Sixty-Day Response to NRC Bulletin 2003-02, "Leakage from Reactor Pressure Vessel Lower Head Penetrations and Reactor Coolant Pressure Boundary Integrity" On August 21, 2003, the NRC issued NRC Bulletin 2003-02, "Leakage from Reactor Pressure Vessel Lower Head Penetrations and Reactor Coolant Pressure Boundary Integrity." This bulletin requires the following information be submitted to the NRC within 60 days after plant restart following the next inspection of the reactor pressure vessel lower head penetrations:
"a summary of the inspections performed, the extent of the inspections, the methods used, a description of the as-found condition of the lower head, any findings of relevant indications of through-wall leakage, and a summary of the disposition of any findings of boric acid deposits and any corrective actions taken as a result of indications found."
Pursuant to 10 CFR 50.54, "Conditions of licenses," paragraph (f), Attachment I to this letter provides the Byron Station, Unit 1 60-day response. This response is due to the NRC by December 15, 2003.
.\0 09
December 12, 2003 U.S. Nuclear Regulatory Commission Page 2 Should you have any questions or desire additional information regarding this letter, please contact William Grundmann, Regulatory Assurance Manager, at (815) 406-2800.
I declare under penalty of perjury that the foregoing is true and correct.
Respectfully, Executed on ______ / °__3___
Stephen E. Kuczynski Site Vice President Byron Nuclear Generating Station
Enclosures:
Attachment 1, Byron Station Unit 1 Sixty-Day Response to NRC Bulletin 2003-02 cc: Regional Administrator - NRC Region III NRC Senior Resident Inspector - Byron Station
ATTACHMENT I Byron Station Unit I Sixty-Day Response to NRC Bulletin 2003-02 "Leakage from Reactor Pressure Vessel Lower Head Penetrations and Reactor Coolant Pressure Boundary Integrity"
Attachment I Byron Station Unit I Sixty-Day Response to NRC Bulletin 2003-02 On August 21, 2003, the NRC issued NRC Bulletin 2003-02, "Leakage from Reactor Pressure Vessel Lower Head Penetrations and Reactor Coolant Pressure Boundary Integrity." This bulletin requires the following information be submitted to the NRC within 60 days of plant restart following the next inspection of the reactor pressure vessel (RPV) lower head penetrations:
Within 60 days of plant restartfollowing the next inspection of the RPV lower head penetrations, the subject PWR addresseesshould submit to the NRC a summary of the inspectionsperformed, the extent of the inspections, the methods used, a description of the as-found condition of the lower head, any findings of relevant indications of through-wallleakage, and a summary of the disposition of any findings of boric acid deposits and any corrective actions taken as a result of indicationsfound.
Response
Summary of the Inspections Performed, Extent of the Inspections, and Methods Used A remote visual inspection of the Unit 1 RPV bottom mounted instrumentation (BMI) nozzles (58 total) and RPV lower head was performed in Mode 5 descending during Byron Unit 1 refueling outage 12 (B1 R1 2) in Fall 2003. The inspection, performed by VT-2 qualified personnel, examined the full circumference around each BMI nozzle on the RPV lower head using multiple passes (i.e., four total) to ensure full coverage with overlap. The inspection was performed in accordance with procedure ER-AP-335-1012, 'Visual Examination of PWR Reactor Vessel Head Penetrations." The inspection used remote equipment capable of resolving the appropriate detail (i.e., VT-1/1C character height in accordance with 1992 ASME Boiler and Pressure Vessel Code Section Xl, Table IWA-2210-1) at two feet. The actual distances viewed were less than two feet which gave extremely close views of the BMI nozzle to RPV lower head interface region, thereby ensuring any boric acid leakage would be easily identified.
Description of the As-Found Condition, Findings of Relevant Indications, and Summary of the Disposition of any Findings The RPV lower head visual inspection identified no evidence of any boric acid deposits in the BMI nozzle to RPV lower head interface region. However, it was apparent the reactor cavity boot seals had leaked borated water down the side of the RPV during previous refueling outages. This was documented in the corrective action program. The RPV lower head also had a minor layer of surface corrosion with no discernable thickness that in many locations had become flaky and was easily removed with little effort. These findings were found to be acceptable as no RPV boric acid leakage was identified and no wastage was observed.
Page 1 of 2
~~~~~~~~
C C~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Attachment I Corrective Actions Taken There were no corrective actions taken as a result of indications found as no evidence of RPV boric acid leakage was identified. The RPV lower head and the BMI nozzle to RPV lower head interface regions were cleaned using a low-pressure (approximately 1200 psi) plain water power wash. The low-pressure wash removed the lightly adhered, flaky rust material and boron residue from the cavity boot seal leak and left the normal surface oxidation layer intact. This was done to ensure a crisp demarcation between the BMI nozzle and the RPV lower head for future inspections.
Page 2 of 2