IR 05000003/2007010
| ML12335A624 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 05/13/2008 |
| From: | Gamberoni M NRC/NRR/DIRS/IRIB |
| To: | Joseph E Pollock Entergy Nuclear Operations |
| SECY RAS | |
| References | |
| RAS 21644, 50-247-LR, 50-286-LR, ASLBP 07-858-03-LR-BD01, EA-08-088 IR-07-010 | |
| Download: ML12335A624 (56) | |
Text
United States Nuclear Regulatory Commission Official Hearing Exhibit RIV000067 Entergy Nuclear Operations, Inc. Submitted: December 22, 2011 In the Matter of:
(Indian Point Nuclear Generating Units 2 and 3)
ASLBP #: 07-858-03-LR-BD01 Docket #: 05000247 l 05000286 Exhibit #: RIV000067-00-BD01 Identified: 10/15/2012 Admitted: 10/15/2012 Withdrawn:
Rejected: Stricken:
Other:
May 13, 2008 EA-08-088 Mr. Joseph Pollock Site Vice President Entergy Nuclear Operations, Inc.
Indian Point Energy Center 450 Broadway, GSB P.O. Box 249 Buchanan, NY 10511-0249 SUBJECT: INDIAN POINT NUCLEAR GENERATING UNITS 1 & 2 - NRC INSPECTION REPORT NOS. 05000003/2007010 and 05000247/2007010
Dear Mr. Pollock:
On May 7, 2008, the U.S. Nuclear Regulatory Commission (NRC) completed an inspection at Indian Point Nuclear Generating Units 1 & 2. The purpose of this inspection, initiated on November 7, 2007, was to assess your site groundwater characterization conclusions and the associated radiological significance relative to Entergy=s discovery of a small amount of contaminated water leaking from the Unit 2 spent fuel pool, and the subsequent discovery of additional subsurface groundwater contamination emanating from the Unit 1 spent fuel pool system. This inspection focused on assessing Entergy=s groundwater investigation to evaluate the extent of contamination, and the effectiveness of actions, taken or planned, to effect appropriate mitigation and remediation of the condition.
The inspection involved an examination of activities conducted under Entergys license as they relate to safety and compliance with the Commission=s rules and regulations, and with the conditions of the license. Within these areas, the inspection consisted of a selected examination of procedures and representative records, observations of activities, interviews with personnel, and independent analytical and assessment activities. This inspection effort reviewed Entergys long-term monitoring plan intended for continuing verification and validation of the effectiveness of the licensees efforts to assess, mitigate and remediate on-site groundwater conditions relative to public health and safety and protection of the environment. Details associated with the long term monitoring program will continue to be the subject of ongoing NRC inspection. The NRC will also continue split sampling for analytical comparison of selected groundwater monitoring wells through 2008. During the course of this inspection, we coordinated activities with representatives of the New York State Department of Environmental Conservation, who observed our inspection and contributed valuable expertise and independent assessment relative to its own focus on public health and safety, and environmental protection.
The enclosed inspection report documents the inspection findings, which were discussed on May 7, 2008, with Mr. Don Mayer and other members of your staff. The team found Entergy=s response to identified conditions to be reasonable and technically sound. The existence of on-site groundwater contamination, as well as the circumstances surrounding the causes of leakage and previous opportunities for identification and intervention, have been reviewed in detail. Our inspection determined that public health and safety has not been, nor is likely to be, adversely affected, and the dose consequence to the public that can be attributed to current on-site conditions associated with groundwater contamination is negligible. No significant findings were identified. However, one minor violation with respect to quality control of groundwater sampling is discussed in this report. This violation is not subject to enforcement action in accordance with Section IV of the NRC Enforcement Policy. The NRC plans no further action with regard to this matter; and no response to this letter is required.
Based on a telephone discussion between Messrs. John McCann, Director of Licensing, and Samuel Collins, NRC Region I Regional Administrator, on April 21, 2008, we understand that Entergy has committed to remove and transfer all spent fuel from the Unit 1 Spent Fuel Pool to Indian Points Independent Spent Fuel Storage Installation, and drain the spent fuel pool by December 31, 2008, thereby essentially terminating the source of groundwater contamination from that location. Notwithstanding, it is expected that some water will remain on the bottom of the pool to reduce the potential for airborne contamination, provide shielding, and facilitate the removal of the sediment in early 2009. We understand that Entergy will promptly inform the NRC of any condition that could potentially impact or delay this commitment. Additionally, we understand that Entergy will incorporate the implementation requirements of its Long Term Monitoring Program (LTMP) as regulatory specifications in the Indian Point Energy Centers (IPEC) Off-site Dose Calculation Manual, thereby assuring that the LTMP will be regarded as an extension of the Radiological Effluents Technical Specifications and Radiological Environmental Monitoring Program, which are subject to NRC inspection. During the Exit Meeting on May 7, Entergy agreed to document these commitments to the NRC by May 20, 2008. Please inform us if our understanding is not correct.
In accordance with 10 CFR 2.390 of the NRC's "Rules of Practice," a copy of this letter and its enclosure will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records (PARS) component of the NRC=s document system (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/reading-rm/adams.html (the Public Electronic Reading Room). Further, in light of ongoing public interest in these matters, the NRC has scheduled a public meeting in Cortland, New York on May 20, 2008, as announced by our Meeting Notice dated May 10, 2008, also available at the NRC web site at http://www.nrc.gov/reactors.plant-specific-items/Indian-point-issues.html, to discuss NRCs assessment of Entergys performance and actions to address the groundwater conditions at Indian Point, and the associated impact on public health and safety of the environment.
Sincerely,
/RA/
Marsha K. Gamberoni, Director Division of Reactor Safety Docket Nos: 50-003, 50-247 License Nos: DPR-5, DPR-26 Enclosure: Inspection Report Nos. 05000003/2007010, 05000247/2007010 w/Attachment: Supplemental Information
SUMMARY OF FINDINGS
IR 05000247/2007010 & IR 05000003/2007010; 11/08/2007 - 05/07/2008; Indian Point Nuclear
Generating Station Units 1 & 2; Other Activities - associated with ROP deviation memorandum.
The report covers an inspection of a September 1, 2005, licensee-identified Unit 2 spent fuel pool leak investigation final report and long term monitoring plan; and review of historical leakage involving the Unit 1 spent fuel pool by three regional inspectors, one headquarters hydrology specialist, and a U.S. Geological Survey hydrology specialist. The NRC=s program for overseeing the safe operation of commercial nuclear power reactors is described in NUREG-1649, AReactor Oversight Process, Revision 4, dated December 2006.
NRC - Identified and Self-Revealing Findings
No findings of significance were identified.
Licensee - Identified Violations
None iii
EXECUTIVE SUMMARY Background:
On September 1, 2005, the NRC was informed by Entergy that cracks in a Unit 2 spent fuel pool wall had been discovered during excavation work, and that low levels of radioactive contamination were found in water leaking from the cracks having radionuclides similar to Unit 2 spent fuel pool water. Entergy initiated a prompt investigation to determine the extent of the condition and potential impact on health and safety. Initially, Entergy determined that on-site groundwater in the vicinity of the Unit 2 facility was contaminated with tritium as high as 200,000 picocuries per liter of water (about ten times the EPA drinking water standard). Subsequently,
Entergy initiated actions to perform a comprehensive groundwater site characterization to investigate the extent of on-site groundwater contamination, identify the sources, and mitigate and remediate the condition. This effort required the establishment of several on-site groundwater monitoring wells to characterize groundwater behavior, flow, direction, and migration pathways.
On September 20, 2005, Region I initiated a special inspection of this matter to examine the licensees performance and determine if the contaminated groundwater effected, or could effect, public health and safety. On October 31, 2005, NRCs Executive Director of Operations (EDO)authorized continuing NRC inspection to assess licensee performance of on-site groundwater investigation activities, and independently evaluate and analyze data and samples to assure the effectiveness and adequacy of the licensees efforts. Throughout this effort, the NRC coordinated its inspection activities with the New York State Department of Environmental Conservation (DEC), which initiated its own independent assessment of the groundwater conditions, including observation of NRCs inspection activities.
The NRC issued a special inspection report on March 16, 2006 (ADAMS Accession No.
ML060750842). The report assessed Entergys performance, achievements, and plans relative to radiological and hydrological site characterization; and reported that the on-site groundwater contamination did not, nor was likely to, adversely affect public health and safety. In the report and in subsequent public meetings, NRC indicated that it would continue to inspect licensee performance in this area, including independent evaluation and analysis of data, to assure that Entergy continued to conform to regulatory requirements, and that public health and safety was maintained.
On March 21, 2006, NRCs independent on-site groundwater sample analysis effort first determined that strontium-90 was also a contaminant in the groundwater, a fact that was subsequently confirmed by Entergy and the DEC. This determination resulted in a significant expansion of the on-site groundwater characterization effort since the source of the strontium-90 contaminant was traced to leakage from the Unit 1 Spent Fuel Pool. A full site-wide hydrogeologic investigation was subsequently scoped to include Unit 1 and Unit 3. The NRC inspection charter objectives were similarly revised to provide the necessary oversight. Off-site groundwater samples have also been obtained since the fall of 2005, and have never detected any off-site groundwater contamination.
iv
Since that time, the NRC has continued to inspect and monitor Entergys activities beyond the limits of normal baseline inspection, as authorized by NRCs Executive Director of Operations (EDO). During this period, NRC inspectors closely monitored Entergys groundwater characterization efforts, and performed independent inspection of radiological and hydrological conditions affecting on-site groundwater. Additionally, from early 2006 through January 2008, the NRC kept interested Federal, State, and Local government stakeholders informed of current conditions through routine bi-weekly teleconferences.
Status of Current Activities, Plans, and Inspection Results:
On January 11, 2008, Entergy submitted the results of its comprehensive ground water investigation, and included its plan for remediation and long-term monitoring of the on-site groundwater conditions. In its report, Entergy described the sources of the groundwater contamination to be the Unit 1 and Unit 2 spent fuel pools. While both pools contributed to the tritium contamination of groundwater, leakage from the Unit 1 spent fuel pool was determined to be the source of other contaminants such as strontium-90, cesium-137, and nickel-63. Entergy identified its plan to remove all fuel from the Unit 1 spent fuel pool to an on-site storage location and drain the spent fuel pool system by the end of 2008, thereby essentially eliminating the source of the groundwater contamination from that facility. Some water is expected to remain in the bottom of the pool to reduce the potential for airborne contamination and provide shielding until the residual sludge is removed in early 2009. In the January 11, 2008 report, Entergy described its actions to repair or mitigate all identified potential leak locations in the Unit 2 spent fuel pool system that may have contributed to the on-site tritium-contaminated groundwater in the vicinity of that facility.
Notwithstanding, residual radioactivity is expected to continue to impact on-site groundwater for the duration of licensed activities. On-site groundwater is expected to continue to be monitored and reported as an abnormal liquid release in accordance with NRC regulatory requirements.
No off-site groundwater has been impacted, since the on-site groundwater flow is to the discharge canal and the Hudson River. Accordingly, the licensee has established a long-term monitoring strategy for the purpose of evaluating the effect and progress of the natural attenuation of residual contamination, informing and confirming groundwater behavior as currently indicated by the existing site conceptual model, and determining changes in conditions that may be indicative of new or additional leakage.
Entergys performance and effectiveness relative to successfully draining water from the Unit 1 spent fuel pool system by the end of 2008, and the quality and effectiveness of its long-term monitoring program, will be the immediate focus of NRCs continuing inspection of Entergys performance and conformance with regulatory requirements relative to the existing groundwater conditions. Additionally, NRC will continue to inspect the efficacy of the licensees long-term monitoring program as part of the Reactor Oversight Process pertaining to radiological environmental and effluents inspection activities.
Notwithstanding, radiological significance from the groundwater conditions at Indian Point is currently, and is expected to remain negligible with respect to impact on public health and safety and the environment. NRC has confirmed with the New York State Department of Health, that drinking water is not derived from groundwater or the Hudson River in the areas surrounding or v
influenced by effluent release from Indian Point. Accordingly, the only human exposure pathway of merit is from the possible consumption of aquatic foods from the Hudson River, such as fish and invertebrates. Dose assessment of the potential for exposure from this pathway, continues to indicate that the hypothetical maximally exposed individual would be subject to no more than a very small fraction of the NRC regulatory limit for liquid radiological effluent release.
Status of Current Inspection Results:
1. Upon the initial identification of conditions that provided evidence of an abnormal radiological effluent release affecting ground water, the licensee implemented actions that conformed to the radiological survey requirements of 10 CFR 20.1501 to ensure compliance with dose limits for individual members of the public as specified in 10 CFR 20.1302, including: (1) promptly investigating and evaluating the radiological conditions and potential hazards affecting groundwater conditions, on- and off-site; (2) annually reporting the condition, and determining that the calculated hypothetical dose to the maximally exposed member of the public was well below established NRC regulatory requirements for liquid radiological release; (3) confirming, through off-site environmental sampling and analyses, that plant-related radioactivity was not distinguishable from background; (4) initiating appropriate actions to mitigate and remediate the conditions to assure that NRC regulatory dose limits to members of the public and the environment were not exceeded; and (5) developing the bases for a long-term monitoring program to ensure continuing assessment of groundwater effluent release and reporting of the residual radioactivity affecting the groundwater. Additional refinement of the long term monitoring program is expected to occur as data is collected and evaluated to verify and validate the effectiveness of expected natural attenuation of the existing groundwater plumes, and to ensure the timely detection of new or additional leakage affecting ground water.
2. The determination of contaminated on-site groundwater conditions at Indian Point was the result of the licensees investigation of potential leakage from the Unit 2 Spent Fuel Pool initiated in September 2005, and subsequent development and application of a series of ground water monitoring wells to determine the extent of that condition. No evidence was found that indicated that the events at Indian Point, that resulted in the on-site groundwater contamination (identified to the NRC on September 1, 2005), were the result of the licensees failure to meet a regulatory requirement or standard, where the cause of the condition was reasonably within the licensees ability to foresee and correct, and should have been prevented. This determination is based on: interviews with licensee personnel; comprehensive review of pertinent documentation, including previous condition reports, survey records, radiological liquid effluent and environmental monitoring reports, records of historical spills and leaks documented in accordance with 10 CFR 50.75, Reporting and Recordkeeping for Decommissioning Planning; and extensive on-site NRC inspection to confirm licensee conformance with required regulatory requirements.
3. The current contaminated groundwater conditions at Indian Point Energy Center are the result of leakage associated with the Unit 1 and Unit 2 spent fuel pool (SFP) systems.
No other systems, structures, or components were identified as contributors to the continuing on-site contamination of ground water.
vi
4. Entergys hydrogeologic site characterization studies provided sufficiently detailed field observations, monitoring, and test data which supported the development and confirmation of a reasonable conceptual site model of groundwater flow and transport behavior. An independent analysis of groundwater transport through fractured bedrock utilizing geophysical well logging data was conducted by the U.S. Geological Survey (USGS). The USGS assessment corroborated the groundwater transport characteristics that were determined by Entergys contractor.
5. Entergys hydrogeologic site characterization and developed conceptual site model provide a reasonable basis to support the determination that the liquid effluent releases from the affected spent fuel pool systems migrate in the subsurface to the west, and partially discharge to the sites discharge canal, with the remainder moving to the Hudson River. Current data and information indicates that contaminated groundwater from the site does not migrate off-site except to the Hudson River. This conceptual site model of groundwater behavior and flow characteristics is supported by the results of independent groundwater sampling and analyses conducted by NRC, which have not detected any radioactivity distinguishable from background in the established on-site boundary monitoring well locations, or in various off-site environmental monitoring locations.
6. Currently, there is no drinking water exposure pathway to humans that is affected by the contaminated groundwater conditions at Indian Point Energy Center. Potable water sources in the area of concern are not presently derived from groundwater sources or the Hudson River, a fact confirmed by the New York State Department of Health. The principal exposure pathway to humans is from the assumed consumption of aquatic foods (i.e., fish or invertebrates) taken from the Hudson River in the vicinity of Indian Point that has the potential to be affected by radiological effluent releases.
Notwithstanding, no radioactivity distinguishable from background was detected during the most recent sampling and analysis of fish and crabs taken from the affected portion of the Hudson River and designated control locations.
7. The annual calculated exposure to the maximum exposed hypothetical individual, based on application of Regulatory Guide 1.109, Calculation of Annual Doses to Man from Routine Release of Reactor Effluents for the Purpose of Evaluation Compliance with 10 CFR Part 50, Appendix I, relative to the liquid effluent aquatic food exposure pathway is currently, and expected to remain, less than 0.1 % of the NRCs As Low As is Reasonably Achievable (ALARA) guidelines of Appendix I of Part 50 (3 mrem/yr total body and 10 mrem/yr maximum organ), which is considered to be negligible with respect to public health and safety, and the environment.
8. All identified liner flaws in the Unit 2 spent fuel pool, and the initially identified crack affecting the Unit 2 spent fuel pool system have been repaired or mitigated. However, not all Unit 2 fuel pool surfaces are accessible for examination. No measurable leakage is discernable from evaporative losses based on Unit 2 fuel pool water makeup inventory data. Unit 1 spent fuel pool water is being processed continuously to reduce the radioactive concentration at the source prior to leakage into the groundwater, and actions have been initiated to effect the complete removal of spent fuel and essentially all the water from the Unit 1 Spent Fuel Pool system by the end of 2008, thereby terminating the source of 99.9% of the dose significant strontium-90 and nickel-63 contaminants (the remaining 0.1% is represented by the Unit 2 and Unit 1 hydrogen-3 (tritium)contaminants). Entergys selected remediation approach for the contaminated groundwater conditions appears reasonable and commensurate with the present radiological risk.
vii
9. The historical duration of leakage from the Unit 1 and Unit 2 spent fuel pool systems that resulted in groundwater contamination is indeterminate. The evidence indicates that the volume of leakage was small compared to the available water inventory, and was much less than the normally expected evaporative losses from spent fuel pools. This conclusion is based on NRC staff review and assessment of spent fuel pool makeup inventory records and applicable leakage collection data, the results of the continuously implemented Radiological Environmental Monitoring Program affecting the Indian Point site, and evaluation of the developed hydrogeologic groundwater transport model.
Accordingly, there is no evidence of any significant leak or loss of radioactive water inventory from the site that was discernable in the off-site environment.
10. No releases were observed or detected from Unit 3.
11. The conditions surrounding the leaking Unit 1 spent fuel pool are based on a leakage rate of 10 drops per second (about 25 gallons per day) that was identified in 1992. At that time, the licensee performed a hypothetical bounding dose impact that concluded that there was negligible dose impact to the public caused by this condition. This licensee assessment was inspected and evaluated, at that time, by NRC inspectors.
This early bounding hypothetical calculation agrees with the dose impact now confirmed by the recently completed hydrogeologic site investigation, and NRCs independent assessment. Based on extensive review of the circumstances and inspection records from that period, it appears that the licensee was in conformance with the standards, policy, and regulatory requirements that prevailed at that time.
viii
REPORT DETAILS
OTHER ACTIVITIES (OA)
4OA5 Other Activities
.1 Overview of the Groundwater Contamination Investigation
In September 2005, a crack was discovered leaking on the outside of the Unit 2 spent fuel pool south wall (approximately 30 feet below the top) during excavation of the spent fuel building loading bay. The NRC initiated a special inspection on September 21, 2005, to investigate the implications of the observed Unit 2 spent fuel pool leakage. Based on analysis of the radionuclide concentrations in the Unit 2 spent fuel pool and maximum bounding pool makeup losses, a bounding dose calculation based on direct release to the Hudson River indicated a tiny fraction of 1 mrem (0.00002 mrem/yr) as the estimated dose to the maximally exposed hypothetical individual. Though the radiological significance of the circumstance was negligible, the condition was unexpected. Accordingly, NRC Region I was authorized by the Executive Director of Operations (EDO) to conduct additional oversight inspection of licensee performance and the circumstances surrounding this contamination issue to better understand the condition and examine possible generic implications, since similar conditions had been identified at other facilities.
Due to the complicated nature of the groundwater characterization effort at Indian Point (i.e., a relatively small site containing two operating units and one unit in SAFSTOR, built on a complex fractured bedrock foundation that required sophisticated analysis and modeling to fully understand groundwater behavior), the EDO renewed the increased inspection authorization each year to permit active and frequent inspection oversight. As a result, inspection of the Indian Point contaminated groundwater conditions evolved to include not only radiological environmental and effluent expertise from Region I, but also hydrological assessment expertise from NRCs Office of Research, and later, from the US Geological Survey (USGS). The application of such resources permitted the NRC to conduct several independent reviews and assessments of data, information, and analysis on which the licensee based its conclusions and determinations.
In addition, the NRC and USGS specialists, worked closely with the New York State Department of Environmental Conservations (NYS DEC) by sharing data and assessment information, coordinating independent split sampling of various sample media, and providing a combined oversight of licensee performance.
On November 7, 2005, the licensee began installing a series of monitoring wells on-site, based on an initial understanding of on-site groundwater flow patterns and associated contaminant transport. Thirty-six monitoring wells were installed over the next 2 years, with the final well installed and operational by the end of August 2007. The groundwater monitoring network ultimately developed by Entergy includes these plus a number of previously existing monitoring locations. Various geophysical evaluations and analyses, including groundwater table mapping, ground permeability measurements and groundwater gradient calculations, were performed and two site-wide hydrology tests were conducted to observe groundwater response in a network of monitoring wells. These tests included a 3-day duration groundwater pump-down test from the Unit 2 spent fuel pool (SFP) leak location, and injection of a tracer dye at the base of the Unit 2 SFP to trace its path across the site.
This body of information was utilized by Entergy to determine the sources of the groundwater contamination, evaluate the potential for leak mitigation through pumping, and confirm the site groundwater transport model through a final tracer test. Throughout the investigation frequent iterations were made to refine the extent of groundwater contamination, the total amount of contaminant released to the environment, and the resulting public dose assessment to ensure that public health and safety were maintained.
As additional wells were drilled and sampled, gradually the full extent of on-site ground water contamination was revealed. A short synopsis providing the significant highlights of the licensees investigation follows, with a more detailed timeline provided in Attachment 1, Timeline Synopsis.
On February 27, 2006, hydrogen-3 (tritium) contamination was detected in a monitoring well beyond the discharge canal, providing the first evidence of potentially contaminated groundwater being directly released into the Hudson River. On February 28, 2006, the licensee developed a new groundwater release bounding calculation methodology based on an overall site rainfall recharge into several discrete site drainage areas to the Hudson River. On March 21, 2006, radionuclides other than tritium (strontium-90 and nickel-63)were first discovered in a monitoring well, which was later determined to be associated with the Unit 1 spent fuel pool system.
On April 24, 2006, utilizing a rainfall recharge water mass balance approach to calculate groundwater flow and more recent monitoring well data utilizing the maximum concentrations of hydrogen-3 (tritium), strontium-90, and nickel-63, a new revised public dose estimate (from the hypothetical consumption of fish) indicated a maximum hypothetical public dose of 0.0025 mrem/yr to the total body and a maximum of 0.011 mrem/yr to the highest organ (adult bone). These values represent about 0.1% of the regulatory specification for liquid effluent releases contained in the Offsite Dose Calculation Manual. This specification is derived from 10CFR50, Appendix I, As Low As is Reasonably Achievable (ALARA) design objectives for liquid effluent releases.
The basis for calculating public doses is site specific, and at Indian Point, is based on the hypothetical, assumed consumption of fresh water fish and salt water invertebrates. Due to a higher dose significance of strontium-90 detected in groundwater releases, Entergy revised its Off-site Dose Calculation Manual (ODCM) to include the analysis of strontium-90 in environmental media, such as fish and invertebrates collected from the Hudson River. Consumption of fish was assumed notwithstanding the fact that the New York State Department of Health publishes health advisories for sport and game fish and recommends very limited or no consumption of fish be taken from the lower reaches of the Hudson River due to mercury and Poly-Chlorinated Biphenyls (PCB) contaminants.
Subsequently, during the summer of 2006, Entergy collected and analyzed fish from the Hudson River, and strontium-90 was identified in one fish collected near the plant as well as in several fish caught in a control location 20 miles upstream of the plant at similar concentrations. In order to resolve whether the strontium-90 was plant-related or the result of existing background levels (Sr-90 exists in environment due to weapons-related fallout),an expanded fish sampling program was devised by the New York State DEC. The program included an additional 90 mile upstream sample location, the collection of specific fish species identified by the States biologist as having limited migratory behavior, and a three-way split of the edible fish portions of the prepared samples between NRC, Entergy, and the NYS DEC. The effort was conducted in June 2007. In the expanded samples, all three independent analytical laboratories reported results that indicated that no plant-related radioactivity was detected or distinguishable from background. To date, no offsite environmental samples (other than water samples from the discharge canal and the tidally influenced intake structure) have indicated any detectable plant-related radionuclides, The USGS performed an independent fracture flow analysis to determine on-site groundwater flow utilizing different data and methods than Entergy to compare groundwater flow results with the licensee. This provided a comparison of fracture flow dominated groundwater flow with the licensees groundwater flow results based on an assumption of general porous media flow through dense fracture sets in the ground. No significant differences were observed from these comparisons, which essentially confirmed that either model of groundwater transport flow provided valid results.
On January 11, 2008, Entergy submitted a hydrogeologic site investigation final report to the NRC documenting closure of the groundwater investigation, adoption of selected remediation actions, and a plan for the continued long-term monitoring of the existing contaminant plumes (ADAMS Accession No. ML080320600). On January 25, 2008, Entergy submitted a synopsis of the long term monitoring plan basis to describe a groundwater monitoring network and a sampling schedule to continue monitoring the existing plumes, detect any future Unit 2 spent fuel pool leaks, and detect any future leaks from any other plant systems structures or components at the site (ADAMS Accession No.
This inspection report provides NRC review of the above mentioned licensee activities.
Continued NRC inspection will continue through 2008 of the removal of spent fuel and draining of the leaking Unit 1 spent fuel pool, split sampling to verify the basis of licensees off-site dose assessment, and review of further development and refinements to the licensees long term monitoring plan. Inspection findings will be documented in future reports.
.2 Final Groundwater Contamination Characterization
By the end of 2007, based on over 900 monitoring well samples, the extent of the on-site subsurface contamination had been mapped and the sources have been determined. Two on-site plumes were discovered emanating from the Unit 2 and Unit 1 spent fuel pool regions, respectively. Due to the influence of the Unit 1 building foundation drain system, some of the Unit 2 plume was drawn into the Unit 1 area, with both plumes intermingling and following a converging path westward towards the Hudson River. Both plumes were relatively shallow (less than 200 feet below ground surface) following a common groundwater trough between Units 1 and 2, and a groundwater transport velocity of between 4 and 9 feet per day, covering a total distance of about 400 feet to the Hudson River (see Figure 1). Approximately one-half of the combined plumes are being intercepted by the plant discharge canal which allows for substantial dilution of this fraction and is a monitored discharge path. The other portion of the combined plumes flows below the discharge canal and discharges directly into the bottom of the Hudson River.
Due to limited groundwater sampling of the new river front monitoring wells across normal seasonal groundwater flow variations, no trend in plume concentrations is yet discernable.
Current contaminant concentrations detected from monitoring wells closest to the Hudson River indicate 9,000 pCi/L of hydrogen-3 (tritium) and 27 pCi/L of strontium-90. A map of monitoring well locations and a table of radionuclide concentration values at each monitoring well are provided in Attachment 2.
These concentrations are slightly below the minimum required effluent release detection sensitivities for these radionuclides (i.e., 10,000 pCi/L for hydrogen-3 (tritium) and 50 pCi/L for strontium-90), and well below the maximum allowable liquid effluent release ALARA guidelines of ten times the effluent concentrations in 10 CFR 20, Appendix B, Table 2, Column 2 (10,000,000 pCi/L for hydrogen-3 (tritium) and 5,000 pCi/L for strontium-90).
NRC required calculation of the maximum dose to a hypothetical person consuming fish and invertebrates at the site boundary, indicates less than 0.1% of design objectives for liquid effluents (3 mrem total body and 10 mrem maximum organ). Since the groundwater contamination is considered an abnormal release, the condition is required to be quantified, evaluated and reported in the annual radiological effluent release reports.
.3 Groundwater Sampling
a. Inspection Scope
During the licensees groundwater investigation, over 900 groundwater samples were collected and analyzed from the established on-site monitoring well network by the end of 2007. The analytical results provide the basis for assessing the extent of the groundwater plume and for performing calculations of offsite doses to members of the public. In order to assess Entergys performance in this area, the NRC implemented an independent split sample collection program with the licensee beginning in September 2005. The monitoring wells selected for independent verification included the southern boundary wells and those bordering the Hudson River that were utilized in effluent release and dose assessment calculations. Sample identity was assured by chain-of-custody procedures that included sample collection observation by the NRC or a representative of the NYS DEC. The NRC samples were analyzed by an independent government laboratory. The NRC samples were sent to the NRC contract laboratory, the Oak Ridge Institute for Science and Education (ORISE), Environmental Site Survey and Assessment Program (ESSAP) radioanalytical laboratory.
By the end of 2007, over 250 split groundwater samples were obtained to provide an independent check of Entergys analytical results and to independently verify if there was any detectable migration of groundwater contaminants offsite. These split samples represent over 1,000 analyses, primarily for hydrogen-3 (tritium), strontium-90, nickel-63, and gamma-emitting radionuclides that characterized the effluent releases. Analyses for other radionuclides were performed, but none were detected.
Various in-plant contamination sources (the Unit 1 and 2 spent fuel pools and others) were also sampled and analyzed by the NRC for a complete range of radionuclides to evaluate the known and potential leaking sources of radioactivity, and to ensure an adequate scope of radionuclide analysis was conducted by the licensee in their groundwater sampling campaign. In addition, the NRC analyzed miscellaneous environmental samples of interest including offsite water supply sources, Hudson River aquatic vegetation, and fish samples. The New York State DEC also provided confirmation of the licensees sample analysis results through a parallel split sample program. This provided for a three-way laboratory comparison of many of the offsite release and environment-critical sample results. This three-way data comparison provided for timely identification of any discrepant sample results potentially affecting offsite releases.
b. Findings
and Assessment No findings of significance were identified.
In general, Entergy=s groundwater measurements of radioactivity were of good quality and of sufficient sensitivity to assess radiological impact. The quality of Entergy=s measurements were confirmed by various split samples analyzed by NRC and the State of New York, (i.e., the Department of Environmental Conservation and the Department of Health). Of the over 1000 results that were reviewed, there were some sample disagreements based on the statistical comparison criteria specified in NRC Inspection Procedure 84750, Radioactive Waste Treatment, and Effluent and Environmental Monitoring. A discussion of the sample disagreements is provided below.
- Between March and September 18, 2006, Entergy reported some strontium-90 results associated with the Unit 1 plume that were low when compared to NRC results. Entergys results indicated that the Unit 1 spent fuel pool cleanup system had shown a reduction in the associated groundwater plume concentrations over a relatively short period of time. There was no other consequence due to this disparity. Entergy initiated an investigation into this issue with their offsite contract laboratory. The investigation did not identify a definitive cause. As a result, Entergy terminated its contract with the lab and procured the services of another offsite laboratory. Entergys reanalysis of the samples confirmed that the original results were low. The reanalysis results were subsequently in agreement with the NRC laboratory results.
- Entergy reported no detectable nickel-63 contamination in four samples from Monitoring Well-42 taken on November 16-17, 2006. Since Monitoring Well-42 is closest to the Unit 1 SFP, and other radionuclides analyzed at the same location remained at expected levels, this indication was not considered reasonable and was also not in agreement with the New York State or NRC laboratory results.
This resulted in an investigation into this issue by the licensees new off-site contract laboratory. Improper procedure protocol was identified and additional controls were implemented to correct this issue. Reanalysis of the nickel-63 results were in agreement with the NRC laboratory results. No other significant sample anomalies were identified by the NRC through the end of 2007.
The above NRC-identified discrepancies highlighted the need for quality control in the licensees sample acquisition and laboratory processing and measurement processes.
Oversight of offsite laboratory analysis of samples was not originally specified by the licensee for on-site groundwater sampling. NRC radiological environmental monitoring program laboratory quality control requirements, specify radionuclide detection sensitivities, and require blind blank samples and blind radionuclide-spiked samples to be provided by the licensee as a check on the off-site laboratorys analytical performance. These requirements apply to the offsite radiological environmental monitoring program, but no requirements are specified for on-site groundwater sample quality controls.
NRC radiological effluent sampling analyses also require laboratory quality controls as specified above. On February 27, 2006, based on detecting hydrogen-3 (tritium) in a monitoring well near the Hudson River, Entergy revised their bounding dose calculation and began calculating actual effluent releases via the groundwater pathway. At this point in the groundwater investigation, the quality assurance of groundwater sample analyses used in effluent reporting became a requirement. However, the offsite laboratory analyses of groundwater samples were not independently evaluated by Entergy until more than one year later. Technical Specifications Section 5.4.1(a)specifies written procedures shall be established, implemented, and maintained covering Appendix A of Regulatory Guide 1.33, Revision 2, which specifies quality assurance requirements for procedures associated with the control of radioactive effluents released to the environment. The inadequate procedure (O-CY-1420, Rev. 1), constitutes a violation of minor significance that is not subject to enforcement action in accordance with Section IV of the NRC Enforcement Policy. There was no actual or potential consequence of this procedure deficiency, because in function, the NRC and NYS DEC split sampling program provided a very effective verification of Entergys laboratory sample analysis program during the groundwater investigation by assuring the accuracy of analytical results.
To address this concern, in May 2007, Entergy initiated an on-site groundwater sampling quality control program incorporating a blind blank sample and blind radionuclide-spiked sample program to verify its own offsite laboratory analytical results. In addition, Entergys corrective action program is still addressing the quality control program requirements relative to groundwater sample analysis, with corrective action responsibilities transferred to the corporate group for resolution (CR-HQN-2007-00894).
NRC split sample analysis comparison of the licensees groundwater sample results are expected to continue until such time as Entergy has addressed all of the concerns associated with laboratory quality assurance issue.
Due to the presence of strontium-90 in groundwater monitoring wells close to the Hudson River, Entergy modified their environmental monitoring analysis of fish samples to include strontium-90 analysis and in September 2006, strontium-90 was detected in one of six fish caught near the plant. Three out of six samples caught 20 miles upstream at the control location also contained similar detectable levels of strontium-90. Entergy concluded that no strontium-90 was detected above background based on similar results obtained from the control location. Strontium-90 is not uniquely generated by nuclear power plants, but was also generated from above ground nuclear testing in the early 1950s and 1960s and now exists ubiquitously in the environment. From a review of applicable scientific literature, comparable levels of strontium-90 that were detected in the September 2006 fish samples were also indicated in background fish testing results in other parts of New York State.
To further clarify the origin of the strontium-90 and confirm the efficacy of utilizing Entergys control location in monitoring background strontium-90 concentrations in fish, an expanded fish sampling program was conducted in June 2007 led by NYS DEC, in consultation with its fish biologists, to ensure that the control location is sufficiently removed from Indian Point to preclude fish migration and to accurately represent background levels of strontium-90. This expanded fish sampling program collected fish samples from three Hudson River locations: an area influenced by liquid releases from Indian Point, a control location 20 miles upstream, and a special control location 90 miles upstream in the Catskills. Three-way split fish samples were supplied to Entergy, NYS DEC and NRC for inter-laboratory comparison of these results. Neither strontium-90 nor any plant-related radionuclides were detected in any edible fish samples by any of the three participating laboratories at any of the three Hudson River locations. This is considered significant, since public doses from liquid discharges from Indian Point are calculated based on assumed fish and invertebrate consumption. This confirms the results expected from the groundwater effluent and normal plant liquid effluent release calculations, indicating small fractions of one millirem per year to the maximally exposed hypothetical member of the public that consumes fish and invertebrates.
.4 Dose Assessment
a. Inspection Scope
Groundwater effluent discharges and associated hypothetical dose calculations to the public involve a two-step process. First, a groundwater transport model is developed to estimate the amount of radioactive material being discharged and its dilution into the environment. The hydrogeologic site investigation of Indian Point has provided the results for determining this aspect of the dose calculation.
Second, based on methods defined in the Indian Point Energy Center Offsite Dose Calculation Manual (ODCM), calculations are performed to determine the maximally exposed individual (infant, child, teen or adult) and maximum organ (bone, kidney, gastro-intestinal tract, liver, thyroid, lung and total body). NRC has confirmed with the NYS Department of Health that groundwater and Hudson River water is not used for drinking or irrigation purposes in the area surrounding Indian Point Energy Center.
Therefore, at Indian Point Energy Center, the liquid effluent dose pathway is through the ingestion of fish and invertebrates (crab). Both the groundwater effluent discharge and the pathway-to-man methodologies and calculation methods were reviewed throughout the licensees investigation in order to ensure that the significance of the liquid effluent releases were bounded and the associated dose impact was evaluated to provide an accurate dose assessment of public health and safety.
b. Findings
and Assessment No findings of significance were identified.
The licensee performed an initial conservative bounding dose calculation, dated October 21, 2005, that assumed a worst case condition, i.e., Unit 2 spent fuel pool water being discharged directly into the Hudson River with minimal Hudson River dilution flow (approximately 100,000 gallons per minute). This dose assessment assumed a conservative Unit 2 SFP leak rate of 2.6 gallons per day1 incorporating all the radionuclides detected. The resultant calculated dose was about 0.0001 millirem/year, well below the ALARA design objectives for liquid effluent releases (3 millirem/year per reactor) and a very small percentage of the public dose limits (100 millirem per year).
The inspectors concluded that the licensee=s preliminary offsite dose calculation utilized conservative assumptions regarding the Unit 2 SFP leak rate and groundwater dilution, appropriately applied the methodology of the licensee=s Offsite Dose Calculation Manual, provided a timely dose evaluation response to the identified condition.
As more data became available, the licensee performed a revision to the conservative bounding calculation, dated December 13, 2005, using Hudson River dilution based on a six hour half-tidal surge. This resulted in a dilution volume of 1.45E10 gallons. This revised bounding dose calculation was based on the actual radioactivity concentration of the Unit-2 SFP and the resultant annual dose to the hypothetical maximally exposed member of the public was calculated to be about 0.0001millirem/year. This revision was based on conservative and reasonable assumptions and agreed with the result from the original bounding calculation.
As on-site groundwater monitoring wells were installed, groundwater sample results were collected, water table contours were identified, and groundwater transport parameters were determined. Entergy developed a site area drainage model based on annual rainfall groundwater recharge water balance and applied maximum monitoring well groundwater concentrations, which was used in a February 28, 2006 effluent release and off-site dose calculation with a result of 0.000015 mrem/yr to the maximally exposed hypothetical member of the public. This was no longer a bounding calculation, but represented an actual groundwater effluent release determination based on groundwater measurements and groundwater drainage calculations. Radiological and hydrogeologic inspection of this method determined that the basis was reasonable and the calculations were accurate.
The basis for the assumed value of 2.6 gallons per day is discussed in Section 5 of this report.
Later in the investigation on March 21, 2006, NRC sample results of Monitoring Well-37 (a river front monitoring well) indicated strontium-90 concentration of 26 pCi/L. This was the first indication that strontium-90 was likely being released directly to the Hudson River through the groundwater. Licensee results confirmed both strontium-90 and nickel-63, in addition to hydrogen-3 (tritium), were likely migrating to the Hudson River. The dose significance for these additional radionuclides is over one hundred times that of hydrogen-3 (tritium). On April 24, 2006, Entergy updated their dose assessment in recognition of this new monitoring well data, and applied the maximum concentrations of hydrogen-3 (tritium), strontium-90 and nickel-63. The resulting groundwater effluent discharge and off-site dose assessment indicated a maximum hypothetical public dose of 0.0025 mrem total body and 0.011 mrem maximum organ dose (adult bone) per year.
The increase from the previous dose estimates is a direct result of the strontium-90 and nickel-63 radionuclides.
As additional groundwater sample data became available, the licensees dose assessment model was further refined to rank the monitoring well sample data in each site drainage area from low to high, and apply a 75th percentile of radionuclide concentration to the dose assessment calculations. This approach was determined to be more realistic and yet still conservative. Utilizing this methodology, abnormal groundwater effluent releases were calculated and the following doses for groundwater releases in 2005 and 2006 were officially reported to the NRC in the annual radiological effluent release reports as follows:
2005: 0.00212 mrem total body and 0.0097 mrem maximum organ (adult bone)2006: 0.00178 mrem total body and 0.0072 mrem maximum organ (adult bone)
Based on discussions with the NRC and USGS hydrologists, Entergy agreed to further evaluate the groundwater flow rate model to utilize groundwater flux calculations based on Darcys Law, a hydrogeological algorithm that considers actual groundwater gradient and soil permeability rather than inferring groundwater flow based on a rainfall infiltration model. Accordingly, Entergy initiated actions to develop a refined method to calculate local drainage area groundwater flux calculations based on Darcys Law while retaining an overall rainfall infiltration as input to the local drainage calculations. Entergy intends to use this approach to calculate and report the 2007 groundwater effluent discharges and dose assessments.
.5 A Unit 2 SFP Leakage
a. Inspection Scope
The Unit 2 SFP does not have a leak detection system, therefore, the licensee used alternative means of assessing the amount of leakage from the spent fuel pool.
Detectable fuel pool inventory loss could not be determined based on fuel pool water makeup records, given the variability in water evaporation loss due to atmospheric temperature, pressure, and humidity variations. A more sensitive indicator of spent fuel pool water loss utilized the trending of spent fuel pool boric acid concentration over time, since boric acid is not affected by evaporative losses and any reduction in boric acid concentration would likely be due to leakage.
The NRC followed Entergys progress in examination of the Unit 2 SFP liner and transfer canal for leaks and subsequent repair of a through-wall leak in the transfer canal.
As was reported in the March 16, 2006 special inspection report, NRC investigation into the capture efficiency of the Unit 1 building foundation drain system indicated approximately seven times more hydrogen-3 (tritium) radioactivity was captured by the drain system than was accounted for by Unit 1 SFP leak calculations. Evidence from the hydrogeologic site investigation confirms the source of this additional tritium radioactivity is from the Unit 2 SFP. Based on this understanding, additional NRC analysis used historical Unit 1 building foundation drain system hydrogen-3 (tritium) sample results to attempt to assess the age and variation of the Unit 2 SFP leak since 1999.
b. Findings
and Assessment No findings of significance were identified.
A review of daily boron concentration measurements in the Unit 2 spent fuel pool since the last refueling outage indicated a decrease of 7 parts per million (ppm) (normally 2,300 ppm) over a one year time period. This measurement provided a bounding water loss value of 2.6 gallons per day (gpd), with a large uncertainty of +/- 7.2 gpd. This uncertainty indicates that no definitive loss of spent fuel pool inventory could actually be determined with any certainty.
The licensee has pursued consistent efforts to inspect the Unit 2 spent fuel pool stainless steel liner for evidence of leaks. Approximately 40% of the liner was inspected by underwater video camera. No leakage was determined on the surfaces examined. The remainder of the pool liner surfaces is inaccessible to optical examination due to limitations imposed by the proximity of the fuel racks and other obstructions. Beginning in July 2007, Entergy lowered the water level in the Unit 2 fuel transfer canal, which is immediately adjacent to the spent fuel pool, in order to examine those surfaces for possible leaks. One pinhole leak was discovered and was subsequently repaired on December 15, 2007. An expert review of the material condition of the leak determined that it was due to an original welding construction flaw, and that there were no indications of any active corrosion on the transfer canal surfaces.
Notwithstanding that all identified potential leak locations have been repaired, most of the spent fuel pool surfaces remain unexamined, with the potential for unidentified leaks remaining. Since the Unit 2 spent fuel pool was constructed without a leak collection system, groundwater monitoring remains the only means for assessing leakage from the Unit 2 spent fuel pool.
.5 B Unit 1 SFP Leakage
a. Inspection Scope
A review of available licensee records was conducted to search for any possible indications of the beginning or duration of the Unit 1 SFP leak. Records were also reviewed to evaluate the licensees response to the initial discovery of Unit 1 SFP leakage, and the adequacy of corrective actions to repair or mitigate the effects of the identified leakage based on regulatory requirements and information known at the time.
b. Findings
and Assessment No findings of significance were identified.
A search for historical Unit 1 control room logs and for Unit 1 spent fuel pool inventory makeup records was initiated, but no pre-1994 records were found. Without those records, which are no longer required to be maintained, no data was available to indicate past water inventory makeup trends. The water makeup records and control room log entries represented the only potential data records to evaluate the onset of Unit 1 SFP leakage, which remains indeterminate.
The initial licensees corrective action program identification and investigation of the leaking Unit 1 SFP (SAO-132 Report 94-06), identified a net fuel pool leak rate (subtracting evaporative losses) of 25 gallons per day, or 10 drops per second, attributed to age-related degradation of the fuel pool epoxy coating, which resulted in pool water penetrating through the fuel pool concrete walls and floors. The corrective actions associated with Report 94-06, included a large scope of investigative activities aimed at identifying potential leakage paths within the Unit 1 plant structures, including groundwater collected in the external Unit 1 building foundation drain system (Figure 2).
Bounding dose calculations performed by the licensee in 1994, which assumed four times the identified leak rate released to the Hudson River, indicated that the resulting dose from such a liquid release would be <0.1% of the liquid effluent regulatory specification and ALARA guidelines.
The NRC conducted three separate team inspections in 1994 (specified in Attachment 1)to assess the licensees identification and resolution of the leaking Unit 1 spent fuel pool condition and based on a comprehensive review concluded that the licensees investigation was responsive to this concern and the potential impact on the public health and environment. Further, that the licensees investigation incorporated all reasonable probable pathways of release and had demonstrated no off-site dose impacts would be attributable to pool leakage based on enhanced environmental surveillance.
Entergys investigative activities did not result in correcting the degraded condition of the Unit 1 spent fuel pools or otherwise eliminate the identified leakage. Unit 1 licensing and procedural requirements were reviewed and no corrective action program violations were identified. NRC requires safety-related functions of plant components to be repaired or corrected in accordance with 10 CFR 50, Appendix B, Criterion XVI. However, the leak rate from the pool did not affect the safety-related function of the Unit 1 spent fuel pool (associated with spent fuel cooling), and the off-site dose consequence of the leakage was evaluated and determined to have no significant dose impact. Therefore, there was no condition adverse to quality and no violation of NRC requirements identified.
This 1992 investigation was the earliest documentation confirming leakage of the Unit 1 SFP. Since 1992, the leakage rate remained constant until the Fall of 2005, when the Unit 1 West SFP was flooded up to allow fuel inspection as part of the future dry cask storage relocation of the spent fuel. After lowering the water level back down and draining the surrounding pools in November 2005, the Unit 1 West SFP leak rate increased to 70 gallons per day due to a higher water pressure forcing more water to drain through the preexisting cracks to the surrounding now drained Unit 1 spent fuel pools. Based on the tritium concentration measured in the Unit 1 West SFP and the current leakage rate, a comparison of tritium leaking from the Unit 1 West SFP and the total tritium collected by the Unit 1 building foundation drain systems could be compared.
Latest calculations indicates that there is approximately three times more tritium collected than can be accounted for from Unit 1 West SFP leakage.2 Based on the hydrogeologic site investigation, it is now known that the source of the additional tritium activity is due to migration of tritium contaminated water from the Unit 2 SFP, in the unsaturated zone southward towards Unit 1 and being drawn into the groundwater cone of depression created by the Unit 1 building foundation drain system.
Recognizing that the Unit 1 West SFP leak condition was stable at about 25 gpd prior to the Fall of 2005 with a stable radioactive source term, historical review of licensee data was used to evaluate the change in the Unit 2 SFP leakage over time since approximately 75% of the tritium collected in the Unit 1 foundation drainage system was due to the Unit 2 SFP leak.
This evaluation was considered necessary to help investigate the results of a sample taken in the Spring of 2000 from Monitoring Well-111 when Entergy was exploring the possibility of purchasing Unit 2. No tritium was detected in the sample. The monitoring well is located in the current Unit 2 SFP tritium plume. The sensitivity of the sample method should have detected any tritium above 270 pCi/L. This fact would indicate that the Unit 2 SFP tritium plume did not exist in the Spring of 2000, and that the SFP leak may have begun more recently. Entergys site characterization report indicates the sample was not a reliable groundwater sample as it was taken from the surface of the well without any purging and was, therefore, not considered representative of the groundwater at this location. In order to determine the efficacy of the Spring 2000 Monitoring Well-111 sample and the possibility of a more recent SFP leak, the Unit 1 building foundation drain collection data was accessed to provide an indication of excess tritium infiltration (attributable to Unit 2 SFP leakage) around the time of the Spring 2000 Monitoring Well-111 sample compared to the present time.
If there was no tritium plume emanating from the Unit 2 SFP at that time, then there should be a significant reduction (approximately 75%) in the tritium input to the Unit 1 building foundation drain system. Otherwise, Entergys site characterization model, The March 16, 2006 Special Inspection Report indicated a higher unaccounted for tritium balance due to a calibration issue with a flow rate monitor, a condition that has been corrected.
which suggests a long-term tritium leak, would be reasonable. The following table summarizes data extracted by the NRC from licensee data. The two Unit 1 building foundation groundwater drain systems consist of the north curtain drain (NCD) and the sphere foundation drain (SFD). The combination of both of these two french drain type systems represents the total tritium collected annually based on weekly sample collections.
Unit 1 Drain Tritium Collection Year SFD SFD flowrate NCD NCD flowrate Total Total flowrate Corrected3 uCi gpm uCi gpm uCi gpm uCi 1999 8.82E4 18 6.0E5 3 6.9E5 21 4.6E4 2005 2.67E4 24 5.8E4 3.6 8.5E4 28 5.6E4 2006 5.2E4 17 4.7E4 4 9.9E4 22 6.6E4 2007 2.6E4 11 2.7E4 2.8 5.3E4 14 5.3E4 As can be seen, in the final corrected column in the table above, there has been a consistent amount of tritium collection in the Unit 1 drain system that predates the due diligence sampling of Monitoring Well-111 in the Spring of 2000. This would indicate that the Unit 2 SFP tritium plume was being captured by the Unit 1 drain system in 1999 as currently characterized, and that the Spring 2000 Monitoring Well-111 sample may not be a valid sample. This confirms the designation as an invalid sample as stated in Entergys hydrogeological final report.
Considering factors including the radiological and non-radiological contamination condition at Unit 1, Entergy determined that any immediate remediation (such as groundwater pump down) of the existing contaminated groundwater in the vicinity of the Unit 2 spent fuel pool would be inappropriate at this time. Such remedial action could adversely affect the current groundwater contamination condition, in particular, it would create a situation in which contaminated water that is currently collected, monitored and discharged from the Unit 1 drain systems in accordance with NRC regulatory requirements, to spread elsewhere unnecessarily. Accordingly, the NRC agrees that, in the absence of any over-riding public health and safety concern, pump and treat remediation of the Unit 2 SFP could adversely affect the spread of the Unit 1 groundwater contamination plume and is not advisable.
.6 Hydrogeologic Investigations
a. Inspection Scope
NRC Region I Inspectors, and scientists from the U.S. Geological Survey (USGS) and NRCs Office of Research made numerous visits to the IPEC site to observe site features, test hole drilling and sampling, rock cores recovered from the test wells, groundwater quality sampling, tracer and pump test procedures, and other site In 2006, the SFD flowrate monitor was found to be significantly overestimating the flow rate by 50%; therefore assuming relatively constant annual groundwater flow, the total tritium results for the prior years was reduced by 50% to provide a normalized comparison.
characterization and monitoring activities. During these site visits, the inspection team interviewed Entergy staff and contractors, i.e., GZA GeoEnvironmental, Inc. (GZA)geotechnical engineers, geologists, and hydrogeologists, and examined their methods, analytical results and bases for conclusions regarding groundwater contamination transport at Indian Point Energy Center.
b. Findings
and Assessment No findings of significance were identified.
The purpose of the hydrogeological investigation was to identify the on-site, and potential off-site, pathways for the abnormal releases, and to define the conceptual site hydrologic model controlling the subsurface transport of the released radionuclides.
Initially there were significant uncertainties in defining the tritium pathway (the first detected abnormal release radionuclide). In discussions with GZA, it was apparent that the tritium source(s) and pathway(s) were not fully defined. Questions were raised as to the groundwater flow direction, which the IPEC FSAR Section 2.5 references indicated was to the south. Based upon water-level data taken by GZA from a series of installed test wells, the groundwater gradient was initially determined to be west to the Hudson River in the vicinity of the Screen Wall Structure building (near Monitoring Well-67).
Upon close examination of the water-level data for the full complement of test wells, the groundwater flow direction was confirmed to be the west and, therefore, the tritium plume was determined to follow the gradient to the Hudson River. Tritium moves at the same rate as the groundwater since it is part of the molecular water composition. Analysis of monitored water levels, temperature and water quality demonstrated tidal effects from the river affecting groundwater flow conditions along the river bank and upgradient to the Discharge Canal.
The question of preferential flow pathways was raised due to the nature of the bedrock underlying the IPEC site, the Inwood Marble, being a metamorphosed carbonate with numerous fractures. These fractures, which can be observed on-site and in the Verplanck Quarry as shown in Figure 3, were inspected for the possibility of solutioning and connectivity. The rock cores collected during the drilling of the test wells were examined for fractures, solutioning and fracture filling. In order to confirm the Entergy/GZA determinations a range of possible conceptual site models were examined to determine the influence of fracturing, solutioning and fracture filling on contaminant transport. In order to fully investigate and independently analyze alternative conceptual site models involving preferential groundwater flow pathways, NRC developed an Interagency Agreement with the USGS - New York Water Science Center located in Troy, New York.
The USGS conducted a detailed flow-log analysis for hydraulic characterization of selected test wells. This analysis examined fracture geometries and hydraulic properties in the bedrock using flow logs, as well as downhole caliper, optical- and acoustic-televiewer, and fluid resistivity and temperature logs, collected in the test wells by Geophysical Applications, Inc. under the direction of GZA. The USGS analysis determined the distribution and character of fracture-flow zones. Hydraulically active fractures were identified in these zones. Transmissivity and hydraulic heads in these flow zones were estimated using the flow-log analysis method. As reported in USGS Open File Report 2008-1123 "Flow-Log Analysis of Hydraulic Characterization of Selected Test Wells at the Indian Point Energy Center (IPEC), Buchanan, New York" (ADAMS Accession No. ML081120119), the flow-log analysis was corroborated with pump test and tracer test results from GZAs site characterization and analyses.
Figure 4 shows the presence of intersecting (conjugate) fracture sets which provide higher permeability zones and create directional flow properties (anisotropy). These analyses were confirmed by pump test results, and later, tracer test results and observations showing distinct fracture zones and variable permeability in the Inwood Marble between the Unit 1 and 2 SFPs extending west to the Discharge Canal. No solution features affecting radionuclide transport were observed or detected by the field testing and USGS independent analysis. However, fracture connectivity was observed and is a contributor to preferential flow and transport, particularly in partially-saturated bedrock (i.e., above the water table) as demonstrated by the GZA tracer test results.
Certain site areas subject to extensive rock backfills, such as the excavated-blast depressions in the transformer yard and along the river, which are porous-flow dominated rather than fracture-flow dominated as indicated in the bedrock.
Early in the investigations, the Discharge Canal was thought to capture the tritium plume.
NRC staff questioned this assumption and encouraged its testing. GZA installed Monitoring Well-37 west of the Canal and down gradient of the plume to test the assumption. Sampling in Monitoring Well-37 confirmed that the tritium plume did continue west under the canal toward the Hudson River; however, a significant amount (perhaps up to 50%) of tritium was captured by the canal. Sampling in Monitoring Well-37 also identified strontium-90 which extended the scope of the investigation.
As the conceptual site model (CSM) was developed using observed tritium and strontium-90 monitored data from the numerous monitoring wells, the role of backfill material around buildings and in excavated depressions (e.g., transformer yard and along the river) was investigated by GZA. The role of storm drains, sump pumps and curtain drains on the local hydrology was also investigated and analyzed. The conceptual site model, as reported in the licensees Hydrogeological Site Investigation Final Report (GZA report), recognized the affect of these features relative to the observed tracer test results and contaminant plume behavior. The conceptual site model incorporated both natural features (e.g., water-levels and flow directions) and human-made features (e.g. building foundations, backfills, curtain drains, storm runoff drains and manholes). The conceptual site model considered percolation to the unsaturated zone, where the Unit 2 tritium source emanates, and flows to the water table. The strontium source was determined to enter the water-table via the north curtain drain surrounding the Unit 1 SFP, and also from the spray foundation sump. Both the tritium and strontium plumes migrate through the connected fractured zones to the Hudson River. Cross-sectional diagrams from the GZA report, shown in Figure 5, depict the flow and transport pathways to the river, including the location of monitoring wells down gradient of the radionuclide sources. Tracer test and radionuclide sampling data from these monitoring wells support the conceptual site model assumptions.
A pump test using Recovery Well-1, with observations in the surrounding monitoring wells, was performed to test the feasibility of a pump, monitor and discharge remediation approach for the tritium plume, and to create a depressed water table (drawdown cone)beneath Unit 2 SFP to capture and provide early detection of abnormal releases. The operation of the Recovery Well-1 caused cesium-137, which had not been previously detected in monitoring wells, to migrate to Monitoring Well-31 and Monitoring Well-32 (west of the Unit 1 and 2 SFPs). This test confirmed the presence of cesium-137 in the fractured rock, and the connectivity of the fractures in the aforementioned fracture zones between the Unit 2 and 1 SFPs. The migration of cesium-137 from Unit 1 to Unit 2 during the test confirmed that the pump test should be conducted at very low pumping rates in the event that other radionuclides were present in the fractured rock and could become mobilized. The fracture filling in the bedrock appears to adsorb the cesium during ambient groundwater flow conditions.
Using insights from this pump test, GZA planned and conducted a tracer test adjacent to Unit 2 SFP at the base of the construction pit where the original abnormal releases of radionuclides were observed. A fluorescein dye tracer was introduced in a shallow borehole above the water table. At the suggestion of NRC staff, the tracer sampling continued for a significantly longer period of time than would be normal to fully detect and analyze the transport pathways. The tracer results confirmed the aforementioned conceptual site model pathways, and identified the role of the fractures in creating preferential transport in the unsaturated zone, and the role of human-made features relative to the observed tritium concentrations in the monitoring wells and Manhole 5 adjacent to Unit 2 SFP. The tracer sampling identified the contaminant pathway direction, transport rate and attenuation for both the tritium and strontium plumes. Since strontium-90 is adsorbed by the fracture filling materials (e.g., clays), the tracer moved at a faster rate than the strontium plume. The residual cesium-137 appears to be relatively immobile due to adsorption and the relatively slow groundwater velocity in the fracture zones until increased by local flow perturbations such as groundwater pumping.
The extensive IPEC site characterization data as reported in the GZA report includes:
water levels; tidal effects; upward and downward flow components determined by flow meters and by using the Waterloo packers (i.e. inflatable bladders to vertically isolate fracture zones in a well); tritium and strontium concentrations; and pump and tracer test results. This database provides valuable site-specific information to confirm the conceptual site model (CSM) and dose calculations. This information also provides a valuable two-year baseline for future long-term monitoring and re-evaluation of the conceptual site model since seasonal groundwater flow dynamics, episodic recharge and potential future releases may alter the assumptions in the CSM. This information is also critical in determining the adequacy of the Entergys chosen remediation approach of monitored natural attenuation for the tritium and strontium-90 plumes.
Monitored natural attenuation refers to the natural groundwater removal of residual contaminants after the source of contamination has been secured, and the radioactive decay acts to diminish the remaining residual radioactivity. Monitored natural attenuation requires the elimination of the contaminant sources, detailed monitoring of the plumes behavior through a confirmatory groundwater monitoring program and confirmation of the conceptual site model, over time.
The licensee indicated that its long-term groundwater monitoring program will incorporate monitored natural attenuation and have a detection capability for potential future abnormal releases. Future NRC inspection will review the program details to focus on achieving the goals of monitored natural attenuation and detecting future leaks. Specific areas of review include determining which monitoring wells and what monitoring frequencies are needed to demonstrate monitored natural attenuation, early radionuclide leak detection and if the assumptions in the conceptual site model are valid. The long-term groundwater monitoring program will be reviewed in a future NRC inspection to ensure there is sufficient detection sensitivity and monitoring frequency to detect changes in Unit 2 SFP leakage and the capability to detect leaks from other plant components in the presence of existing groundwater contamination.
.7 Prior Indications of On-site Groundwater Tritium Contamination
a. Inspection Scope
The inspectors reviewed NRC required documentation affecting the identification of potential and actual leaks of radioactivity outside of plant systems. The records were reviewed to identify any historical survey data that the licensee possessed that would indicate prior knowledge of any groundwater contamination issue that was not evaluated as required. Title 10 CFR 50.75(g) requires records to be retained of past on-site contamination spills. These records for the Indian Point site were reviewed for relevance to the current site condition.
NRC IE Bulletin No. 80-10, AContamination of Nonradioactive System and Resulting Potential for Unmonitored, Uncontrolled Release of Radioactivity to Environment@,
requires licensees to review their facility design and operations to identify nonradioactive systems, that could become radioactive through interfaces with radioactive systems, to include leaks and valve misalignments. The Bulletin required routine sampling and analysis for the identified nonradioactive plant systems be established in order to identify any contaminating events that could lead to unmonitored, uncontrolled releases to the environment. In response to the Bulletin, the licensee developed lists of affected plant systems and sampling periods. The inspectors also reviewed the licensees program for the sampling of on-site storm drain systems for radioactive liquids and sediments. Also, the inspectors reviewed the results of the due diligence sampling that was conducted in early 2000 to identify outside plant areas with residual contamination. These results were also screened for potential evidence of the preexisting groundwater contamination condition.
b. Findings
and Assessment No findings of significance were identified.
The 10 CFR 50.75(g) decommissioning file included records of the prior Unit 2 SFP leak from October 1, 1990 - June 9, 1992 as documented in corrective action report (SAO-132, 92-08). These records indicate an effective cause determination and repair of the condition. In addition all affected soil was excavated to a depth of eight feet and the affected 35 cubic yards of soil was shipped off-site as radioactive waste, with no residual soil contamination remaining. No evidence of groundwater contamination was determined.
The Unit 1 SFP leak assessment corrective action report (SAO 132 94-06) and hydrology report (Whitman 1994) were included in the decommissioning file, identifying that most of the 25 gpd leak identified in 1992 would be intercepted by the Unit 1 building foundation drain system. Any portion not intercepted by the drain system would likely follow a shallow ground water flow pathway into a small stream discharging into the Hudson River some 1700 feet southwest of Unit 1. Based on this information, the licensee added environmental sampling stations to include the small stream south of Indian Point as well as the Trap Rock Quarry (0.7 miles south of the plant) and an unused groundwater well located off of Fifth Street in the town of Verplanck (1.3 miles south of Indian Point). Environmental records of those sampling activities did not identify any radioactivity in these samples that was plant-related.
Decommissioning file records of the Unit 2 SFP leak that was discovered in September 2005, includes records indicating a 2.6 gpd bounding leak rate was determined in a November 21, 2005, boron-loss mass balance calculation. The current hydrogeologic site investigation report completes the groundwater contamination records in the 10 CFR 50.75(g) decommissioning file.
Other miscellaneous documents were reviewed including some legacy records of low level Cs-137 contamination found in, and associated with, Unit 1 storm drain lines (1-50 picocuries per gram) that predated commercial operation of Units 2 and 3. One area, 10 feet X 70 feet X 3 feet deep, identified in July 1990 on the north side of the Unit 3 fuel storage building, was originally excavated storm drain material with residual levels of Cs-137 (30 pCi/g) from Unit 1 operations; it was later paved over. This action included a dose evaluation which indicated the area would result in much less than 1mrem/yr, which would not require immediate cleanup in accordance with NRC site cleanup screening level of 5 mrem/yr (NUREG/CR-5849).
Review of the due diligence site assessment conducted by Canberra Services on February 14 - 22, 2000, identified various areas inside the restricted area with detectable radioactivity. Several monitoring wells were installed and sampled. None of the groundwater samples indicated any detectable plant-related radioactivity.
The IE Bulletin 80-10 program specific to on-site storm drain monitoring was fairly extensive and provided detailed records since 1981. Review of the site wide storm drain system data did not indicate a history of the current extent of elevated tritium contamination. No historical marker was indicated in the storm drain sample data as to when the tritium leaks may have been initiated.
Entergys IE Bulletin 80-10 program (IPEC Storm Drain Sampling Procedure, O-CY-151-, Rev. 3) has been recently revised, consolidating two previously separate Unit-specific programs with an updated map of the Unit 1, 2 and 3 storm drain systems, and incorporating a consolidated sampling schedule, with appropriate frequencies, that includes monthly sampling for sensitive storm drain outfalls. The improved program now includes specific sample detection criteria requiring management involvement.
.8 Remediation and Long Term Monitoring Plans
a. Inspection Scope
In addition to providing the hydrogeologic site investigation final report to the NRC on January 14, 2008, a subsequent Memorandum dated January 25, 2008 (ADAMS Accession No. ML, 080290204) provided a synopsis of the Long Term Monitoring Plan Bases. These documents were reviewed along with a number of Entergy and GZA implementing procedures that provide a framework for addressing the current and future groundwater contamination issue. Several meetings were also held between the NRC, USGS and NYS DEC in January and February 2008 to discuss the adequacy of Entergys plans and procedures.
b. Findings
and Assessment No findings of significance were identified.
Based on the installation of on-site monitoring wells, 36 out of 39 monitoring wells were selected by Entergy for continued sampling at established frequencies. In addition, three storm drain manholes were included in the sampling plan to monitor drainage from the Unit 2 containment footer drain and the Unit 3 foundation and containment footer drains.
This initial sampling program consists of 378 annual samples to provide trending information on the current contaminant plumes and provide for early detection of leakage from other potential on-site sources to comply with the requirements of NEI 07-07, Industry Ground Water Protection Initiative, for early detection and reporting of on-site spills or inadvertent contamination of groundwater.
In addition, the on-site storm drain system for Units 1, 2 and 3 was visually inspected using remote camera technology and large volumes of material (over 100 tons) were removed to complete the inspection and make requisite repairs. During NRC inspection of prior sampling evidence of groundwater contamination, in the March 16, 2006, special inspection report, the storm drain sampling program was assessed as a segregated program (between the operating Units) without proper program administration or data trending review. Since those observations, Entergy has renovated the storm drain systems, validated their connections and flow directions, and consolidated the program into one site-wide program with individual sample detection criteria that initiates management review. The current storm drain sampling program requires over 140 samples per year to detect potentially leaking plant systems as part of the IE Bulletin 80-10 requirement.
Currently, there is no periodic trending review of storm drain sampling data or use of this program with the groundwater monitoring program. Since one of the main functions of storm drains is to remove surface runoff water, many of the storm drains included in the sampling program may not provide any indication of below ground leaking plant systems or components. Since the site groundwater investigation has established the water table and groundwater gradients, the licensee has initiated actions to evaluate the storm drain systems for additional input to the long-term monitoring program.
The long term monitoring plan implementing procedures incorporate periodic sampling from a groundwater monitoring network composed of 36 monitoring wells and numerous other sampling locations. The current groundwater plumes are mapped spatially among this network of monitoring wells to allow future monitoring of the plumes footprint. At the conclusion of this inspection, the licensee was still in the process of defining and establishing the parameters of its long-term monitoring program.
Early in the Unit 2 spent fuel pool leak investigation, Entergy reviewed detailed fuel pool boron sampling data in an effort to determine net leakage losses from the fuel pool, since boron loss would not be affected by pool evaporative losses and any reduction in boron concentration would be due to pool leakage. Transfers of spent fuel and reactor water during refueling outages set a new boron solution level and trends of boron concentration losses after each refueling outage. This trending of boron data provided an initial Unit 2 SFP loss rate of approximately 2.6 gallons per day (approximately 1 drop per second)calculated by Entergy in September 2005. Although there are some complicating factors (e.g., variance in boron data measurement and any unidentified fuel pool cooling system leaks), this approach does provide an early indication of net change in spent fuel pool leakage.
Entergy plans on removing the spent fuel and draining the Unit 1 spent fuel pools by the end of 2008. Some water may remain in the bottom of the pool to reduce the possibility of airborne contamination and provide shielding of remaining sludge. Sludge removal is expected to be completed in early 2009. After completion of these activities, the source of the Unit 1 plume will be eliminated allowing residual radioactivity removal through continued purging from the Unit 1 building foundation drain system and through natural attenuation processes. Relative to Unit 2, the licensee has taken action to repair all identified liner leak imperfections, and has identified a program for monitored natural attenuation on the presumption that leakage has been terminated, based on its current assessment of groundwater tritium concentrations. However, neither the licensee nor the NRC is conclusive at this time, since only 40% of the liner surface was accessible for inspection; and it is too early to detect any significant decline in tritium concentrations (with respect to the natural variability in groundwater flow). Notwithstanding, it is expected that the licensees implementation of its long-term monitoring program will establish sufficient data to permit a conclusive determination in the near term.
The current dose significance of the Unit 2 SFP tritium leak rate is 1000 times lower than the current Unit 1 plume (approximately 0.000002 mrem/yr versus 0.002 mrem/year), and therefore, additional actions beyond long-term groundwater monitoring of both groundwater plumes by Entergy are not warranted and the current approach is acceptable to the NRC.
Further definition of the long term monitoring plan and licensee commitment to this groundwater surveillance program will be pursued through continuing inspection activities in 2008. These future inspection activities will verify completion of Entergys planned remediation activities, and to review plume attenuation results to confirm Entergys site groundwater characterization conclusions.
.9 Regulatory Requirements
a. Inspection Scope
The following regulations were reviewed to identify any areas of noncompliance.
The NRC regulates the radioactive effluent releases from nuclear power plants through guidelines based on instantaneous maximum concentration values specific for each radionuclide as well as regulatory limits on potential doses to the public. The release limits are based on 100 mrem total effective dose equivalent per year. In addition, licensees are required to meet the ALARA design objective guidelines of 3 mrem to the total body per reactor and 10 mrem to the maximum organ dose receptor per reactor (10CFR50, Appendix I). There are also total site annual exposure limits to actual members of the public from all pathways of 25 mrem to the whole body, 75 mrem to the thyroid and 25 mrem to any other organ (40CFR190.10(a)).
Effluent releases are reported by each nuclear power plant licensee to the NRC on an annual basis with calculated maximum doses to the public and comparison to the above indicated NRC limits. In addition, to provide a verification of these calculated releases, a radiological environmental monitoring program is conducted by the licensee providing off-site environmental sample measurement results for biologically sensitive pathways of exposure to man especially in locations directly downstream or downwind of the nuclear power plant. Spills or leaks on the site property are required to be recorded to support future decommissioning activities (10CFR50.75(g)).
Unless drinking water is provided from on-site groundwater wells, the environmental monitoring program does not require on-site groundwater monitoring. This area of the regulations is currently under review. The industry has adopted a Groundwater Protection Initiative (Nuclear Energy Institute; NEI 07-07, August 2007) to initiate on-site groundwater monitoring at all nuclear power plants, and the NRC is proposing additional rulemaking and guidance (10 CFR 20.1406 and Regulatory Guide 4.21) to address the potential for leaks into the groundwater and the need to monitor this potential effluent pathway.
b. Findings
and Assessment No findings of significance were identified.
Instantaneous release rates are limited by procedures that establish gaseous and liquid release radiation monitor system setpoints and automatic discharge valve closures.
Based on review of monitoring well sample results from October 2005 through December 2007, groundwater effluent instantaneous release concentrations were always a small fraction of the regulatory limits.
The annual and quarterly liquid effluent public doses were calculated annually for 2005 and quarterly and annually for 2006 based on a rain precipitation water infiltration drainage model developed by Entergys hydrogeologists to derive groundwater flux values to drive the contamination concentrations obtained from monitoring well sample results. In 2005, when few samples were available, the maximum monitoring well sample results were used in the calculations. For the quarterly 2006 groundwater effluent calculations, when multiple sample results were available, the monitoring well sample results were ranked (low to high) and the 75th percentile values were used to derive a best estimate of the groundwater releases to the Hudson River. A half-tidal surge of the Hudson River was used as a final dilution of these releases and dose calculations were performed based on the Indian Point Energy Center Off-site Dose Calculation Manual (ODCM) methodology. The ODCM incorporates exposure pathway dose calculations based on Regulatory Guide 1.109. Doses were calculated based on Hudson River specific bioaccumulation of contaminants in fish flesh and based on infant, child, teen and adult fish consumption rates. Various organs concentrate various radionuclides at differing rates, so doses are calculated for bone, liver, total body, thyroid, kidney, lungs, and gastrointestinal tract, based on applicable dose factors for each critical organ. The maximum age group and organ is reported.
For 2005 and 2006, the following doses were reported for both normal and groundwater liquid effluents.
2005 Liquid Units 1 & 2 Unit 3 Limit Max % of Effluents (mrem) (mrem) (mrem) Limit Routine max 2.93E-4 TB4 3.29E-4 1.5 0.02 quarter 4.68E-4 O5 TB 5 0.009 3.85E-4 O
Routine 8.11E-4 TB 4.45E-4 3 0.098 TB6 annual 1.31E-3 O TB 10 0.11 O6 5.4E-4 O
Groundwater 2.12E-3 TB 3 0.07 annual 9.72E-3 O 10 0.1 2006 Liquid Effluents Routine max 7.04E-4 TB 6.8E-5 1.5 0.05 quarter 1.03E-3 O TB 5 0.02 7.6E-5 O Routine 8.8E-4 TB 1.27E-4 3 0.09 TB6 annual 1.26E-3 O TB 10 0.085 O6 1.6E-4 O
Groundwater 1.78E-3 TB 3 0.06 annual 7.21E-3 O 10 0.07 These maximum hypothetical doses represent approximately 0.1% of the ALARA design objectives for liquid effluents (3 mrem and 10 mrem per year per reactor) for Units 1 and 2, combined with the groundwater releases attributed to Units 1 and 2.
In conclusion, based on a review of applicable NRC radiation protection regulations, all effluent and environmental survey and reporting requirements have been met, indicating that the existing groundwater contamination conditions represent a small fraction of regulatory limits and no violation of these requirements have been identified.
TB - Total Body exposure O - Maximum Organ exposure Represents total dose from Units 1&2 and groundwater
4OA6 Meetings, including Exit
.1 Exit Meeting Summary
The inspectors presented the Inspection results to Mr. D. Mayer and other licensee and New York State representatives on May 7, 2008. The licensee acknowledged the findings presented. Based upon discussions with the licensee, none of the information presented at the exit meeting and included in this report was considered proprietary.
Figure 1 Long Term Monitoring Plan Figure 2 Unit 1 Building Foundation Drain System Figure 3 Observed bedding and conjugate fractures in Verplanck Quarry (from USGS)
Figure 4 Downhole Flow Meter and Geophysical Survey Example from Monitoring Well Monitoring Well-58 Figure 5 Unit 2 Spent Fuel Pool Tritium Plume Cross Section ATTACHMENT 1 Indian Point Contaminated Groundwater Investigation Time Line Date Event Unit 1 Spent Fuel Pool Timeline Unit 1 ceased commercial operations on October 31, 1974
1. April 1990: A nuclear plant operator observed higher than usual frequency of fuel pool
makeup than usual, initiated an investigation by Con Edison.
2. 1991: Con Edison began sampling the north curtain drain (NCD) and sphere foundation
drain sump (SFDS) for tritium and established separate liquid discharge paths.
3. May 1992: Completed calculations of unaccounted water loss - 25 gpd leakage.
4. May 1994: A task force organization was created with a Unit 1 SFP Project Manager position
reporting to the Plant General Manager. Individuals from Chemistry, Operations Maintenance, Health Physics and Engineering were represented.
5. May-June 1994: NRC inspection (Drs. Bores and Jang) to investigate Unit 1 SFP leakage
(50-03/94-01) Boron concentration mass balance indicated 91 gpd leak rate to the SFDS and 1.5 gpd to the north curtain drain. Tritium concentration mass balance indicated 73 gpd to the SFDS and 1.2 gpd to the NCD. Hydrogeologist study indicated that the groundwater movement was about 10 ft/day and would flow towards the quarry, not the Hudson River. No violations were identified.
6. July 1994: Whitman hydrogeology report investigation of Unit 1 SFP leak migration
concluded that most of the leakage would be captured by the Unit 1 building foundation drain system and the rest would migrate to the South in the shallow zone and could be detected in the creek bordering south of the plant and in the Trap Rock Quarry. These sample locations were added to the REMP program.
7. August 1994: NRC inspection (Bores/Jang) to review licensees leak investigation (50-03/94-
02). Hydrogeologist completed study indicated that groundwater at the site flowed upward and either west or south into the Hudson River. No violations were identified.
8. December 1994: NRC inspection (Bores, Jang, Erikson, Noggle) inspect compliance with
Bulletin 94-01 (fuel pool potential siphoning), leak investigation, and SAFSTOR approval (50-3/94-80). Confirmation of tritium in the sphere foundation drain sump that drains groundwater from the bottom of the Chemical Systems Building of Unit 1 in May 1994, provided evidence that the Unit 1 SFP system was leaking beyond the plant structure and resulted in initiating a corrective action SAO-132 report (94-06). 10CFR50.59 evaluations between March 9, 1992 and December 1994 were reviewed and found to be complete and met requirements. In October 1994, boron concentration was increased in the SFP and fluoresce in dye tracer was added to the water storage pool to detect these sources in the NCD and SFDS. As of mid-December, no increased boron or indications of tracer were detected in either of these Unit 1 drains. Tracer did indicate that the SFDS had been discharging through a Unit 3 storm drain to the discharge canal. Con Edison subsequently rerouted this discharge by hard pipe through the Unit 1 River water system into the discharge canal. NCD was diverted to the Unit 1 sphere sump where this discharge was pumped to the liquid radwaste processing system. The on-site stream was added to REMP monitoring for tritium on a quarterly basis. No violations were identified.
9. January 2, 1996: SECY-96-01, Decommissioning Plan for SAFSTOR and amendment of
license for Unit 1 was approved.
10. June-August 1996: NRC inspection (Jang) to review followup actions: modification to north curtain drain for recapture, new RMS detector installed in SFDS (50-3/96-04).
11. February-March 1998: NRC inspection (Jang) to review followup actions: effluent controls and trending of SFP inventory (50-3/98-02).
12. May-June 1998: NRC inspection (Ragland) reviewed schedule for draining and cleanout of pools (50-03/98-04). Con Edison removed all irradiated hardware from both the East and West Unit 1 SFPs.
13. November-December 1998: NRC inspection (Ragland) verified that irradiated hardware had been removed from the East pool and shipped off-site during May-August 1998, with the East pool ready for desludging and draining. PCBs detected in water storage pool sludge. (50-03/98-17).
14. December 1998-February 1999: NRC SAFSTOR inspection (Dimitriadis) (50-03/98-19).
Work in progress in draining and desludging various pools. While desludging the water storage pool, PCBs were detected. Due to known leakage of this pool, the NCD was diverted into the Unit 1 sphere annulus for waste processing.
15. April-June 1999: NRC inspection (50-03/99-03) NRR reviewed a Unit 1 safety evaluation for modifications to the SFPs.
16. June-July 1999: NRC inspection (Ragland) reviewed monitoring of pool leakage, north curtain drain water was being treated by mechanical and charcoal filtration. Water storage pool cleanup in progress (50-03/99-06).
17. April 7, 2003: Unit 1 Remediation plan was approved to accomplish several objectives that included pursuing sealing the Unit 1 East SFP, transferring the spent fuel into that pool, and draining the leaking Unit 1 West SFP, thereby stopping the leak.
18. 2004: Insitu dry storage option was proposed by Unit 1 project team to stop the leak. Too many uncertainties surfaced regarding potential airborne radioactivity and future floodup effects on fuel integrity upon final spent fuel removal.
19. September 19-November 17, 2005: The Unit 1 West SFP was flooded up for spent fuel inspection for material condition evaluation. After drain down, Unit 1 SFP leak rate recalculated to be 70 gpd.
20. January 16, 2006: Unit 1 drain system collects seven times more tritium than can be attributed to the current 1 SFP leak rate.
21. March 21, 2006: NRC sample results of Monitoring Well-37 strontium-90 analyses were received indicating 26 pCi/L. This was the first indication that strontium-90 was likely being released in the groundwater to the Hudson River. Initial bounding calculations were revised, indicating less than 0.1% of effluent release limits.
22. April 17, 2006: Due to the 3/21/06 discovery of strontium-90 in Monitoring Well-111, the licensee initiated demineralization of the Unit 1 SFP 40 hrs per week in order to reduce leaking source term. Final assessment of Unit 1 SFP leakage calculations indicated 70 gpd post-drain down since November 2005.
23. April 24, 2006: Updated dose assessment based on 2/28/2006 methodology using more recent monitoring well data and maximum concentrations of hydrogen-3 (tritium), strontium-90 and nickel-63: 2.5E-3 mrem total body and 1.1E-2 mrem maximum organ (adult bone).
Strontium-90 analysis was added to REMP fish, Hudson River and sediment samples.
24. August 9, 2006: After completing a temporary system modification, Entergy began continuous cleanup of the Unit 1 West SFP.
25. November 13-17, 2006: NRC on-site team inspection to review Unit 1 SFP leak history and hydrology results of a 3-day pump down test of Recovery Well-1.
26. April 2007: Revised calculation of tritium mass balance for Unit 1 SFP based on total radioactivity per year (based on 65 gpd leak rate) versus total radioactivity collected in the Unit 1 building drains for 2006. The Unit 1 SFP releases accounted for only 30% of the tritium collected in the Unit 1 drain system.
27. June 6-22, 2007: An expanded control zone fish split sampling exercise was conducted to include a second control location in the Catskills to help evaluate background levels of strontium-90 in fish.
Unit 2 Spent Fuel Pool Timeline Operating license issued September 28, 1973
1. October 1, 1990: Unit 2 SFP stainless steel liner was perforated by a diver during re-rack
cutting operation, but was not identified at that time.
2. May 7, 1992: Unit 2 SFP liner was discovered to be leaking (about 50 gpd), due to outside
visible boric acid deposits on the wall of the fuel service building. Condition report determined cause and examined all other liner work areas for similar perforations. Entergy excavated 35 cubic yards of soil to a depth of 8 feet leaving no detectable contamination.
3. June 9, 1992: Under water epoxy temporary patch was installed, sealing the leak.
4. June 12, 1992: A steel box was welded over the liner perforation permanently sealing the
leak completing corrective actions for this fuel pool leak event.
5. September 1, 2005: Initial discovery of the Unit 2 spent fuel pool leak. Contamination was
first detected on a swipe sample of the exposed crack in the SFP south wall excavation area at approximately 65-foot elevation. The NRC resident inspector was informed.
6. September 12-15, 2005: NRC initial radiological scoping inspection and dose assessment,
0.00002 mrem/year based on 2 L/day leak rate.
7. September 20, 2005: NRC Special Inspection Charter was issued, followed by a press
release announcing this action.
8. October 5, 2005: Tritium was discovered in the Unit 2 transformer yard Monitoring Well-111.
This was the first location removed from the Unit 2 SFP indicating a groundwater contamination concern.
9. October 27, 2005: Unit 2 SFP liner inspection begins with underwater camera inspection to
identify any leaks. Visual indications were followed by vacuum box testing.
10. October 31, 2005: NRC Executive Director for Operations issued Reactor Oversight Process deviation memorandum to provide additional NRC resources and continuing NRC inspection of the groundwater contamination investigation through 2006.
11. November 3, 2005: Licensee submitted a non-required 30-day report to the NRC, based on tritium results for Monitoring Well-111 (0.0002 uCi/ml) that were above the radiological environmental monitoring program (REMP) reporting criteria for non-drinking water samples (0.00003 uCi/ml). However, Monitoring Well-111 is an on-site well not representative of an off-site environmental sample therefore, no NRC report was required.
12. November 7, 2005: Drilling of the first new monitoring well was initiated (Monitoring Well-30).
13. January 13, 2006: A permanent leak collection box was installed encompassing the Unit 2 SFP crack.
14. January 31, 2006: A NRC Special Inspection team met on-site to review the Phase 1 monitoring well hydrology results.
15. February 8-10, 2006: A NRC Special Inspection team was on-site to evaluate the licensees compliance with IE Bulletin 80-10 (radiological monitoring of on-site non-contaminated systems),10 CFR 50.75(g) (on-site spill documentation for future decommissioning), and chemistry counting quality control requirements. Hudson River waterfront well sample splits were taken for NRC, NYS and IPEC.
16. February 27, 2006: Monitoring Well-37 initial sample result = 30,000 pCi/L, provided the first indication of a tritium groundwater release directly to the Hudson River.
17. February 28, 2006: Licensee provided a revised dose calculation of 0.000015 mrem/yr to the maximally exposed member of the public based on a general site area hydrology water transport and multiple contamination area drainage model. The NRC conducted the SIT exit meeting.
18. March 16, 2006: NRC Special Inspection Report No. 05000247/2005001 was issued describing NRC=s initial response and evaluation of the Indian Point groundwater contamination issue.
19. March 21, 2006: NRC sample results of Monitoring Well-37 strontium-90 analyses were received indicating 26 pCi/L. This was the first indication that strontium-90 was likely being released directly to the Hudson River. Initial bounding calculations were revised, indicating less than 0.1% of effluent release limits.
20. April 1, 2006: Due to the 2/21/06 discovery of strontium-90 in Monitoring Well-111, the licensee initiated continuous demineralization of the Unit 1 SFP in order to reduce the leaking source term.
21. April 10, 2006: Entergy groundwater monitoring and commitment letter sent to NRC Region I.
22. April 24, 2006: Updated dose assessment based on 2/28/2006 methodology using more recent monitoring well data and maximum concentrations of hydrogen-3 (tritium), strontium-90 and nickel-63: 0.0025 mrem total body and 0.011 mrem maximum organ (adult bone).
23. June 12-16, 2006: NRC groundwater contamination hydrology inspection team was on-site.
U.S. Geological Survey participation was added to the NRC inspection effort.
24. November 7, 2006: NRC split sample results identify licensee strontium-90 results from 8/1 - 9/18/2006 were low and caused licensee resampling and licensee investigation.
25. October 30- November 1, 2006: Entergy conducted a 3-day groundwater draw-down pump test from Recovery Well - 1 (adjacent to Unit 2 SFP).
26. November 13-17, 2006: NRC on-site team inspection to review Unit 1 SFP leak history and hydrology results of a 3-day pump down test of RW-1.
27. February 8, 2007: Fluorescein dye tracer test injected near the base of Unit 2 SFP. Test samples were collected through August 2007.
28. March 21, 2007: NRC inspection team reviewed preliminary tracer test results.
29. May 9-10, 2007: NRC conducted an on-site inspection team review of tracer test results and the evaluation of groundwater transport.
30. June 6-22, 2007: An expanded control zone fish split sampling exercise was conducted to include a second control location in the Catskills to help evaluate background levels of strontium-90 in fish.
31. June 2007: The Unit 2 SFP transfer canal was drained below the pinhole leak, which arrested this leak pathway.
32. July-August 2007: An independent fracture flow analysis using down hole geophysical and flow logs was conducted by the USGS to compare groundwater flow results based on fracture flow with the licensee=s groundwater flow rate calculations derived from packer testing data (slug tests) and based on a general porous media groundwater flow model.
33. August 31, 2007: The last monitoring well was installed and became operational (Monitoring Well-67).
34. November 7-9, 2007: NRC inspection team was on-site to compare and review the final site conceptual groundwater model based on all previously derived site data and USGS analyses.
35. December 15, 2007: The pinhole leak in the Unit 2 SFP transfer canal was repaired.
36. January 14, 2008: NRC received Entergys final site hydrogeological investigation report.
37. January 29, 2008: NRC received Entergys Synopsis of Long Term Monitoring Plan Bases.
38. February 4, 2008: NRC inspection team conducted a critique of the Long Term Monitoring Plan and associated implementing procedures.
39. February 21, 2008: NRC held a meeting with Entergy and GZA to discuss further development and refinement of the Long Term Monitoring Plan.
40. May 7, 2008: NRC conducted an exit meeting of inspection report 50-003/2007010 & 50-247/2007010.
ATTACHMENT 2 Site Groundwater Contaminant Concentrations MONITORING WELL LOCATIONS ANO FUNCTIONS
- e
- Indian Point Monitoring Well Groundwater Contamination Results as of 12/31/2007 in units of pCi/L H-3 Sr-90 Ni-63 Cs-137 Southern Boundary Wells MW-40 ND ND ND ND MW-51 ND ND ND ND Northern Boundary Wells MW-52 ND ND ND ND MW60 ND ND ND ND Eastern Boundary Well MW-65 ND ND ND ND Riverfront Wells MW-60 ND ND ND ND MW-66 9000 11 ND ND MW-67 5000 27 ND ND MW-62 780 2 ND ND MW-63 ND ND ND ND Unit 2 SFP Wells MW-30 130000 ND ND 3000*
MW-31 36000 ND ND 200*
MW-32 14000 ND ND ND MW-33 23000 ND ND ND MW-34 22000 ND ND ND MW-35 6000 ND ND ND MW-111 100000 1 ND ND MW-36 12000 2.5 ND ND MW-37 6000 28 56 ND MW-55 10000 32 ND ND MW-50 4000 47 ND ND MW-49 7000 26 ND ND Unit 1 SFP Wells MW-42 2500 47 200 37000 MW-53 7400 28 ND ND MW-55 10000 32 ND ND MW-50 4000 47 ND ND MW-49 7000 26 ND ND MW-47 3500 4 ND ND MW-56 1500 2 ND ND MW-57 4000 38 ND ND MW-54 2000 20 ND ND MW-58 900 ND ND ND MW-59 800 Unit 3 Wells MW-39 ND 5 ND ND MW-41 ND 6 ND ND MW-45 2200 ND ND ND MW-44 ND ND ND ND MW-43 ND ND ND ND MW-46 1700 ND ND ND U3-T1 530 ND ND ND U3-T2 1200 ND ND ND Off-site Locations LaFarge No. 1 ND ND ND ND LaFarge No. 2 ND ND ND ND LaFarge No. 3 ND ND ND ND Trap Rock Quarry ND ND ND ND 5th Street Well ND ND ND ND Camp Field Reservoir ND ND ND ND New Croton Reservoir ND ND ND ND ND indicates nothing detectable above background
- Single positive result was obtained immediately after a 3-day pump down test indicating hydraulic connectivity between Monitoring Well-42 and Monitoring Well-30 and 31.
These radionuclide concentrations reflect end of 2007 results. Due to annual cyclic groundwater flow variability, no definite trend of the radionuclide concentrations could be conclusively determined at the present time. Additional sample data over time will clarify whether the Unit 1 and Unit 2 groundwater plumes are shrinking in size or concentration.
ATTACHMENT 3
SUPPLEMENTAL INFORMATION
KEY POINTS OF CONTACT
Licensee Personnel
- M. Barvenik Principal Engineer, GZA Geo Environmental, Inc.
- J. Comiotes Director, Nuclear Safety Assurance
- P. Conroy Manager, Licensing
D. Croulet Licensing Engineer
P. Donahue Chemistry Specialist
J. Pollock Site Vice President
C. English Unit 1 Project Engineer
G. Hinrichs Project Engineer
D. Loope Radiation Protection Superintendent
T. Jones Licensing Engineer
R. LaVera Radiological Engineer
- D. Mayer Director, Special Projects
J. Peters Plant Chemist
S. Sandike Chemistry ODCM Specialist
New York State Inspection Observers
- T. Rice Environmental Radiation Specialist, New York State, Department of
Environmental Conservations (NYS DEC)
LIST OF INSPECTIONS PERFORMED
7112203 Radiological Environmental Monitoring Program and Radioactive Material
Control