ML12088A042
| ML12088A042 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 03/14/2012 |
| From: | Gerald Bichof Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 12-088 | |
| Download: ML12088A042 (6) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 March 14, 2012 Attention: Document Control Desk Serial No.: 12-088 U. S. Nuclear Regulatory Commission NAPS: MPW Washington, DC 20555-0001 Docket Nos.: 50-338 50-339 License Nos.: NPF-4 NPF-7 VIRGINIA ELECTRIC AND POWER COMPANY NORTH ANNA POWER STATION UNITS 1 AND 2 INDUSTRY GROUND WATER PROTECTION INITIATIVE VOLUNTARY REPORT This voluntary report is submitted in accordance with NEI 07-07, Industry Ground Water Protection Initiative - Final Guidance Document.
On February 17, 2012, a sample from a ground water sample point was confirmed, by a vendor lab, to contain tritium above the NEI 07-07 voluntary reporting threshold of 20,000 picoCuries per liter (pCi/L). The water sample was obtained as part of ongoing activities to determine the source of tritium previously identified in ground water piezometers. The enclosure describes the event and provides the reporting information specified by NEI 07-07.
Should you have any questions concerning this submittal, please contact Mr. R. B. Evans, Manager Radiological Protection, at (540) 894-2107.
Sincerely, Gerald T. Bischof Site Vice President North Anna Power Station Enclosure Commitments contained in this letter: None 4%O!
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cc: United States Nuclear Regulatory Commission Region II Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, Georgia 30303-1257 NRC Senior Resident Inspector North Anna Power Station Dr. V. Sreenivas NRC Project Manager U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 08 G-9A Rockville, MD 20852-2738 Ms. K. R. Cotton NRC Project Manager U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Mail Stop 08 G-9A Rockville, MD 20852-2738 Mr. Steven Harrison Acting Director, Division Radiological Health Virginia Department of Health 109 Governor Street Room 733 Richmond, VA 23219 Mr. Thomas A. Faha Regional Director Virginia Department of Environmental Quality 13901 Crown Court Woodbridge, VA 22193
Mr. Art Warren Virginia Department of Emergency Management 10501 Trade Court Richmond, VA 23236 Mr. Robert Dube Louisa County Administrator P.O. Box 160 Louisa, VA 23093 Mr. Michael Schlemer Louisa County Emergency Services P.O. Box 160 Louisa, VA 23093 Mr. Edward Everrett Account Engineer American Nuclear Insurers 95 Glastonbury Blvd, Suite 300 Glastonbury, CT 06033-4453
Enclosure Voluntary GPI Report Serial No.12-088 Page 1 of 3
Background
On October 29, 2010, voluntary verbal notifications were made to local and state government agencies including the NRC regarding an increase in tritium levels in one (1) onsite ground water monitoring sample point (PZ-3). This increase in tritium levels, 16,500 picoCuries per liter (pCi/L), did not exceed any NRC regulatory dose limits nor did it exceed the voluntary reporting limits of 20,000 pCi/L specified in NEI 07-07 Industry Ground Water Protection - Final Guidance Document. At that time two (2) adjacent onsite ground water monitoring sample points did not show a similar increase.
None of the eight (8) ground water monitoring sample points surrounding the station outside of the protected area have shown any detectable levels of tritium. All indications show that the tritium in PZ-3 sample point did not migrate to the lake or any drinking water sources. While a verbal notification was made to government agencies, a written report was not made because the voluntary reporting limits specified in NEI 07-07 Industry Ground Water Protection - Final Guidance Document were not exceeded.
An evaluation determined that a possible source could be the Circulating Water Tunnel.
A hydrologist was consulted and recommended the installation of additional sample points to determine the actual source. Subsequently, seven additional ground water sample points were installed in March 2011. Monthly sampling between March 2011 and August 21, 2011 showed no increase in levels above previously reported values. A sample taken August 27, 2011, following the seismic event, did not detect any increase in levels above previously reported values. While Units 1 & 2 were shutdown following the seismic event, inspections were made to the Unit 2 Circulating Water Tunnel and repairs were made. On September 8, 2011, elevated tritium levels were noted in ground water sample point GWP#6 at 20,190 pCi/L, slightly above the reporting threshold. Since the increased levels were suspected to be from the same plume that was previously reported from PZ-3 no additional notifications or reports were made.
Description of the Event On February 17, 2012, North Anna Power Station (NAPS) was notified by its vendor laboratory that a water sample, taken from an onsite ground water sample point (GWP#6), was confirmed to contain tritium above the voluntary reporting threshold of 20,000 picocuries per liter (pCi/L). The water sample, measuring 53,300 pCi/L, was obtained as part of ongoing activities to determine the source of tritium previously reported to the state and NRC on October 29, 2010 (Event Notification - EN46377).
Current hydrological studies have determined the ground water in the area migrates to the station power block which is in the opposite direction from the lake. The ground
Enclosure Voluntary GPI Report Serial No.12-088 Page 2 of 3 Description of the Event (continued) water at the power block is collected in building subsurface drains and transported to a clarifier for processing. Clarifier discharge is accounted for as a monitored liquid effluent release pathway under the radiological effluent control program in accordance with the station's Offsite Dose Calculation Manual. As such, there is no increase to the projected annual dose to a member of the public. There are also no sources of drinking water in this area. Sampling of eight (8) ground water sample points outside the station protected area show no detectable levels of tritium confirming there is no migration offsite.
An event notification was made to the NRC (EN47682) on February 21, 2012 in accordance with 10CFR50.72(b)(2)(xi) for voluntary notification to local and state government agencies. The NRC Resident Inspector was also notified.
Corrective action(s) taken Sampling of eight (8) ground water sample points outside of the station protected area continue to show no detectable levels of tritium. Continued sampling of PZ-3, adjacent to GWP#6, show no detectable levels of tritium. This would indicate successful repairs to the Unit 2 circulating water tunnel thereby eliminating the tunnel as the source of tritium. The Unit 1 Circulating Water Tunnel will be inspected during the 2012 refueling outage with repairs being made as required.
Inspections on above ground piping connected to the Unit 1 Refueling Water Storage Tank (RWST) indentified two leaks which have been contained. The RWST is located adjacent-to ground water sample point GWP#6. A partial portion of underground piping from the RWST was excavated and inspected during the Unit 1 shutdown in the fall of 2011. Visual inspections and ultrasonic testing of this piping were satisfactory.
Additional excavation and inspections of underground piping from the RWST are scheduled during the 2012 Unit 1 refueling outage. In addition, excavations and inspections are planned for underground piping from tanks containing contaminated fluids.
Ground water sample frequency has been increased to ensure tritium levels are not increasing and the ground water continues to migrate to the station power block.
Enclosure Voluntary GPI Report Serial No.12-088 Page 3 of 3 An estimate of the potential or bounding annual dose to a member of the public Current hydrological studies have determined the ground water in the area of PZ-3 and GWP#6 migrates to the station power block which is in the opposite direction from the lake. There are also no sources of drinking water in this area. The ground water at the power block is collected in building subsurface drains and transported to a clarifier for sampling, analysis and discharge. Discharge from the clarifier is accounted for in accordance with the station's Offsite Dose Calculation Manual. As such, there is no increase to the projected annual dose to a member of the public.
Since the projected annual dose to a member of the public is less than the limits in 10 CFR 50 Appendix I corrective actions with respect to projected annual dose are not required.
Additional Information Upon further review the elevated tritium levels that occurred at ground water sample point GWP# 6, on September 8, 2011 should have been reported via a 30 day written report to the NRC. While the elevated levels were from the same plume that was previously reported, only a verbal notification was made the first time on October 29, 2010 since the increase in tritium levels was less that the reporting threshold. As such, a written 30 day report was not required at that time.