ML19095B384
| ML19095B384 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 10/08/2018 |
| From: | Raffenberg M Florida Power & Light Co |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19095B530 | List: |
| References | |
| L-2019-031 | |
| Download: ML19095B384 (11) | |
Text
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 FPL Response to Miami Dade County L-2019-031 Enclosure 2 Page 1 of 11 FPL response to Miami Da~e County July 10, 2018 letter regarding the FPL Site Assessment Report (SAR) dated March 17, 2017 and the SAR Supplemental Information submittal dated November 11, 2017 October 8, 2018
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 October 8, 2018 Wilbur Mayorga, P.E.
FPL Response to Miami Dade County Chief, Environmental Monitoring and Restoration Division Division of Environmental Resources Management 701 N.W. 1st Court 6th Floor Miami, FL 33136-3912 L-2019-031 Enclosure 2 Page 2 of 11 RE:
Miami Dade County July 10, 2018 Letter regarding the FPL Site Assessment Report (SAR) dated March 17, 2017 and the SAR Supplemental Information Submittal dated November 11, 2017
Dear Mr. Mayorga:
This correspondence is in response to your July 10, 2018 letter regarding the Florida Power & Light (FPL)
Site Assessment Report (SAR) dated March 17, 2017 and the SAR Supplemental Information dated November 11, 2017, submitted pursuant to Addendum 1 dated August 15, 2016 of the Consent Agreement between FPL and Miami-Dade County. FPL appreciates your review and approval of the SAR activities and direction related to ammonia concentrations adjacent to the Turkey Point facility. In complying with the July 10th DERM letter, FPL understands that the requirements and obligations of Paragraph 34.c. and d. of the August 15, 2016 Consent Agreement Addendum are met.
In the July 10th letter, DERM states that based on their evaluations:
- 1) Historical data collected since 2010 from groundwater monitoring wells within (TPGW-13) and immediately adjacent to the Cooling Canal System (CCS) (TPGW-1, TPGW-2, TPGW-10, and TPGW-14) indicate a statistically significant increasing trend and a concentration gradient emanating from the CCS at the deep and intermediate intervals.
FPL Response: As noted in the SAR, groundwater ammonia concentrations surrounding the CCS are consistently below Chapter 24-44 Clean-up Target Levels (CTLs) for ammonia in groundwater (Section 24-44.(2)(f)(v) of the Code of Miami-Dade County) and as such, provide an acceptable level of protection for human health, public safety and environmental resources and are below the point at which a site rehabilitation action is determined to be accomplished (Section 24-44.(2)(a) of the Code of Miami-Dade County).
- 2) The total ammonia concentrations documented in several sampling locations at the Barge Basin, Turtle Point Canal, Card Sound Canal, S-20 Get Away Canal, and the Sea-Dade Canal exceeded the applicable Miami-Dade County surface water standard. DERM acknowledges that the documented elevated surface water ammonia concentrations may be attributable to several contributing sources, including factors not directly related to the operation of the CCS.
However, based on an evaluation of other associated water quality data, such as tritium concentrations and temperature, DERM finds that the data supports that the CCS is a
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 Page 2 oflO FPL Response to Miami Dade County L-2019-031 Enclosure 2 Page 3 of 11 contributing source to the ammonia concentrations observed in areas which exceed the applicable standard.
FPL Response: The FPL Site Assessment Report identified ammonia concentrations that exceeded applicable MDC surface water standards in five deep inan made drainage canals adjacent to the CCS. The elevated ammonia values were located in bottom samples where dissolved oxygen levels were less than 1.0 mg/L. Ammonia levels in the middle and upper portions of the water column were compliant with county ammonia standards with the exception of middle samples in the Turtle Point Canal where the dissolved oxygen levels were also less than 1.0 mg/L. There are no state numeric ammonia standards for marine waters.
Average ammonia levels within the CCS canals are well below Chapter 24-42(4) surface water standards of 0.5 ppm (Source: EPU semi-annual data from 6/2010 through 3/2018: 0.33 mg/L and L-31E weekly data from 5/31/2015 through 8/6/2018: 0.26 rrtg/L). Measured ammonia concentrations in several of the deep samples (TPSWC-7D, TPSWC-8D, S20Get-CCS-B, SDC-SWCCS-B, and TPBBSW-8B) greatly exceeded the total nitrogen concentrations in the CCS and in groundwater beneath the CCS demonstrating that there are sources of nitrogen other than the CCS causing exceedances of county ammonia standards in the bottom of the deep canals.
As identified in the SAR, while the data cannot delineate contribution levels of groundwater underlying the CCS to the ammonia levels in surrounding waters, the SAR analysis demonstrated that for those adjacent surface water areas that exceeded the Miami-Dade limit for ammonia, the maximum contribution was 2 percent or less. The SAR also established that the range of contribution (including Surface Waters that met the 0.5 mg/1 standard) ranged from 0.4 to 16 percent. Thus, if there is any contribution to ammonia concentrations in adjacent surface water from groundwater beneath the CCS, it is qe rninirnis.
While offsite groundwater concentrations of ammonia are below action levels established in Chapter 24 of the Code of Miami-Dade County and groundwater concentrations of ammonia provide a de rninirnis contribution to the stratified elevated ammonia found in the stagnant manmade deep canals cut into the Biscayne aquifer, FPL has already taken numerous successful steps and is pursuing additional actions that address nutrient contributions from the Turkey Point facility as outlined below. FPL will continue to work with DERM to assess responses resulting from FPL's implementation of the following actions in good faith that these actions are reasonable, responsive and compliant with the CA, as amended, and with the understanding that elevated surface water ammonia concentrations are attributable to several contributing sources, including factors not directly related to the operation of the CCS.
The FPL strategy to address CCS nutrients consists of three elements: 1) continued implementation of CCS canal practices, 2) external canal practices, and 3) monitoring and reporting. This approach is consistent with FPL 2016 Nutrient Management Plan as required and approved by the Florida Department of Environmental Protection (FDEP) pursuant to Paragraph 21.b of the FDEP 2016 Consent Order.
A summary of DERM's requirements as stated in the July 10, 2018 letter and where they are addressed in this response is provided below:
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 Page 3 of 10 FPL Response to Miami Dade County L-2019-031 Enclosure 2 Page 4 of 11
- 1)
Submit a plan that identifies strategies or actio1?:s FPL shall implement to address CCS nutrient impacts to groundwater and surface water resources beyond the boundaries of the CCS; FPL Response: See Sections 1 and 2
- 2)
Implement the FPL permitted plan to partially fill the Barge Basin and Turtle Point Canal, as well as submittal of plans to fill or otherwise address water quality impacts in the Card Sound; Canal, S-20 Get Away Canal, and the Sea-Dade Canal; FPL Response: See Section 2
- 3)
Resample surface water sampling point SDS-SWCCS; FPL Response: See Section 3
- 4)
Submit a groundwater and surface water monitoring plan to evaluate the effectiveness of the measures implemented pursuant to requirements 1 and 2 above; and FPL Response: See Section 3
- 5)
Expansion of the evaluation of the performance of the DERM approved hypersaline groundwater recovery well system to include an evaluation of the spatial and temporal trends for groundwater ammonia, and a quantification of ammonia mass removal.
FPL Response: See Section 3
- 1.
CCS Canal Practices In September 2016, FPL developed the Nutrient Management Plan for the CCS in compliance with Paragraph 21.b of the FDEP Consent Order that outlined the potential sources of nutrients found in the CCS, including chemical products used for plant operations and included a plan for reducing nutrient levels in the CCS (FPL, 2016). FPL has shared a copy ofthis report with DERM. The report found:
The major source of nutrients in the CCS water column came from the die-off and decomposition of sea grasses between 2010 and 2013, caused by elevated CCS average salinities above 55 psu Additional sources of nutrients are primarily environmental in nature (algae, groundwater seepage, berm erosion and plant biomass, atmospheric deposition, and canal sediment storage)
To a lesser degree, controlled water sources contributed to nutrient concentrations (water added from the L-31E canal, marine wells, interceptor ditch pumpage and Floridan freshening) while industrial sources related to plant operations were a minor contributor to total loading Under the current algae dominated nutrient based canal system, nutrients within the halotolerant cyanobacteria are reintroduced to the water column when algae cells die and release nutrients that support the growth of new algae cells thereby recycle the nutrients in the water column. In order to break this cycle, the CCS canal nutrients need to be reduced to levels which will not sustain the persistent algae dominance and facilitate the re-establishment of seagrasses which for decades had successfully moderated nutrients in the
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 Page 4 of 10 FPL Response to Miami Dade County L-2019-031 Enclosure 2 Page 5 of 11 CCS. The 2016 plan identified target nutrient levels for the CCS at 2.5 mg/L for total nitrogen and 0.02 mg/L for total phosphorous. Target levels are a management guide, subject to variability based on seasonal and environmental factors and should be reviewed on an appropriate averaging interval.
Canal management actions implemented by FPL to date ( canal sediment removal, canal berm management, vegetation management, canal freshening with low nutrient Floridan aquifer, and groundwater extraction) have been effective in reducing nutrient concentrations in the cooling canals and in shallow groundwater near the canals. Since reaching its peak in September 2013, semi-annual total nitrogen concentrations in the CCS canals have dropped from 15.2 mg/L to 3.5 mg/Lin September 2018 with the March and September 2018 levels being the lowest measured since 2011 (Figure 1). Phosphorous concentrations peaked at 0.087 mg/L in September 2014 and have declined to 0.026 mg/L by September 2018 (Figure 2).
Over the past several years, FPL has been evaluating and pilot testing mechanical and biologic means of removing/ sequestering nutrients in the CCS. This plan builds on the information gained in implementing the 2016 nutrient management plan and considers chemical, mechanical and biologic based actions to further reduce CCS nutrients going forward as described below.
Figure 1: Semi-Annual average CCS total nitrogen concentrations: 6/2010 through 9/2018 16.0 14.0
-12.0
..... f 10.0 i" 8.0
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6.0
{:.
4.0 2.0 0.0 Semi-Annual Average CCS Total Nitrogen:
6/2010 - 9/2018 I I I I
I I
I
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 Page 5 of 10 FPL Response to Miami Dade County Figure 2: Semi-Annual average CCS total nitrogen concentrations: 6/2010 through 9/2018 0.1 0.09 0.08
-::, 0.07 tic E 0.06
~ 0.05
] 0.04
(=. 0.03 0.02 0.01 0
Semi-Annual Average CCS Total Phosporous:
6/2010 - 9/2018 I
I I
I I
I CCS Canal Practices; Chemical/Mechanical Treatment Options:
L-2019-031 Enclosure 2 Page 6 of 11 Nutrient and Algae Removal: Actions to remove nutrients in the cooling canal water column and/ or the removal of algal biomass consider both chemical and mechanical means. For the removal of nutrients in the cooling canals, several coagulants and flocculants have been evaluated for in situ applications (where chemical nutrient sequestering occurs within the canal system) and on a treatment plant scale (treatment external to the canals). Trials have included bench testing and pilot scale tests. For removal of algae biomass, FPL has evaluated chemical methods (algaecides) and mechanical treatments (ultrasonic breakdown, filtration, and protein skimming methods using dissolved air flotation).
Challenges identified with chemical and mechanical treatment options included impacts of salinity on performance of flocculants and air flotation methods, cost feasibility of large scale treatment systems, persistence of chemicals introduced to the system, and potential for impacts to fish and wildlife that utilize the CCS. At this time, evaluation of technically, environmentally and economically feasible chemical and/ or mechanical treatment methods suitable for the CCS are ongoing. The following are nutrient reduction actions that have been implemented or are being implemented within the CCS Foam Removal/Harvesting: Cooling water circulation pumps agitates and aerates CCS water containing organic compounds and nutrients. The organic compounds and nutrients increase surface tension of water causing air bubbles to form and stick together into foam. Chemical analyses of the CCS foam indicated the water forming the bubbles is high in nitrogen and phosphorous compared to CCS canal water (10 to 20 times higher per unit volume than canal water). FPL is evaluating the potential for developing a foam collection and condenser system by which foam can be collected, rendered to liquid and disposed of along with hypersaline groundwater from the RWS down the DIW. Pilot testing of foam collection and disposal system has been encouraging (Figure 3). Evaluation of the feasibility of a large scale collection-condensation and disposal system linked to the DIW for disposal is underway.
Salinity Reduction: As a result of temperature, thermal loading via power generation and periods of low rainfall, the CCS experiences periods when evaporation exceeds freshwater recharge and salts, including
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 Page 6 oflO FPL Response to Miami Dade County L-2019-031 Enclosure 2 Page 7 of 11 nutrients, become more concentrated in the CCS. FPL is using fresh water from the upper Floridan aquifer to replace freshwater lost to evaporation to reduce the concentration of salts/nutrients in the CCS.
Reductions of salinity are a necessary component for the re-establishment of seagrass beds within the CCS which remains a proven biologically based nutrient sequestering system in the CCS. Since UFA freshening began in November 28, 2016, the average annual CCS salinities have been dropping despite several significant dry spells. FPL is encouraged by the progress in reducing CCS salinity and is continuing to evaluate additional freshwater sources.
Sediment Maintenance: CCS canal sedimentation impacts thermal efficiency and thereby, the salinity of the CCS. Removal of sediment from the water column and consolidating on berm tops reduces the bioavailability of nutrients within the sediment. Phase I of canal maintenance dredging was completed in 2015 resulting in significant improvements in thermal efficiency. Concurrent reductions in CCS salinities, total phosphorous and total nitrogen concentrations have been observed although it is not clear the degree to which these changes are attributable to maintenance dredging. At this time there are *no immediate plans for additional dredging.
CCS Canal Practices; Biologic Treatment Options:
CCS Berm Maintenance Practices: CCS berms are a source of nutrients that reach the cooling canals as runoff over non-stabilized soil, and transport of plant material. Recent FPL evaluation of Australian pine (Casuarina equisetifalia) in and surrounding the CCS indicates significant amounts of nitrogen and phosphorous are added to the CCS in the form of vegetative litter and decay. Runoff of oxidized soils from non-vegetative berms adds nutrients and associated sediment reduces hydraulic connection of the cooling canals to groundwater. To address this, FPL is implementing a vegetative berm management program including removal of Australian pine and other exotics and restoring native grasses to stabilize berm soils (Figure 4).
Management of berm vegetation uses periodic control burns instead of chemical treatments. Side slope erosion associated with Hurricane Irma is being evaluated to determine whether restoration work is needed.
CCS Seagrass Re-establishment: A healthy sea grass population expected help balance the nutrients in the CCS and sequester nutrients in biomass. A healthy sea grass system will also provide fish and invertebrates protected habitat to grow and reproduce. In September 2018, FPL implemented a field scale test planting of a total of 3 acres of llitppia maritima at separate locations in the CCS to determine whether current conditions will support the repatriation of historic nutrient moderating seagrass meadows in the CCS.
The test plants were pre-conditioned to withstand high salinity water prior to mechanical planting in the CCS (Figure 5). Ruppia maritima was selected as the initial seagrass species due to the higher salinity tolerances of.
the plant and was historically the dominant grass in the CCS. The test planting sites were selected based on screening criteria that considered substrate quality, water depth, light penetration, temperature, and salinity.
Prior to this pilot, several small scale successful planting tests were conducted in the canal system and in test tanks. Based on the results of the pilot, additional test plantings will be considered. Challenges to the success of seagrass plantings are light penetration (limited by cyanobacteria based turbidity) and hypersalinity.
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 Page 7 of 10 FPL Response to Miami Dade County Figure 3: CCS Foam Collection Pilot L-2019-031 Enclosure 2 Page 8 of 11
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 Page 8 of 10 FPL Response to Miami Dade County Figure 5: CCS berm vegetation management pilot site
- 2.
External Canals Practices L-2019-031 Enclosure 2 Page 9 of 11 Canal Restoration /Partial Filling: FPL is moving forward with the restoration of the Barge Canal Turning Basin and the Turtle Point Canal as prescribed in tl1e FDEP CO and requirement 2 ofDERM's July 10, 2018 letter. FPL has received all federal, state and county permits for the project (August 17, 2018),
selected a contractor, issued a notice to proceed (September 26, 2018) with construction to commence by the end of October 2018. Completion of both of the restorations is targeted by August 17, 2020. The two restoration projects entail partially filling the Barge Canal Turning Basin from an average existing depth of -
30 ft. NA VD to a depth of -15 ft.
A VD., and to fill and plant mangroves in the western third of the Turtle Point Canal while filling tl1e remainder of the remnant canal to -7 ft. NA VD (Figures 6 and 7).
Figure 6: Cross section of the Turtle Point canal restoration CROSS-SECTION A-A ltOQ.)0 ZtOCOO lt00.00 5tOl10) 1t00...
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Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 Page 9 of 10 FPL Response to Miami Dade County Figure 7: Cross section of the Barge Basin canal restoration CROSS-SECTION A-A 1l
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Groundwater Extraction: On May 15, 2018 FPL began operation of the approved Turkey Point Groundwater Recovery Well System (RWS). This system removes up to 15 mgd of hypersaline groundwater from the base of the Biscayne Aquifer via a series of ten extraction wells aligned along the western edge of the CCS and north to Palm Drive (FPL RWS Startup Report, 2018). Prior to the start of the RWS, FPL was permitted to conduct extended injection testing of the Turkey Point Class I Deep Injection Well (DI\\v') using 15 mgd of extracted hypersaline groundwater from beneath the CCS from the Biscayne Aquifer from September 29, 2016 to May 15, 2018. During this injection testing period and the first quarter ofRWS operation, at total of 1.8 billion gallons of hypersaline groundwater from the base of the Biscayne aquifer has been removed and disposed of via permitted deep well injection. Based on ammonia data collected from the bottom of the Biscayne Aquifer in TPGW-1D, 2D, and 13D from September 2016 through March 2018 the estimated average ammonia concentration of groundwater extracted was 1.84 mg/ L which indicates approximately 27,600 pounds of ammonia has been removed from groundwater beneath the CCS since September, 2016.
There are no other plans to fill or otherwise address unquantified water quality impacts for the Card Sound Canal, S-20 Get Away Canal, and the Sea-Dade Canal under development. FPL plans to continue implementation of the nutrient reduction actions within the CCS as outlined in this plan and execute the groundwater RWS which has already removed approximately 27,600 pounds of ammonia from groundwater beneath the CCS since September, 2016. To the extent, if any, CCS water has contributed to elevated levels of ammonia in these dead-end canals, the actions taken above are anticipated to minimize or eliminate such contribution.
- 3.
Monitoring and Reporting FPL and MDC DERM have jointly worked on identifying a monitoring program for the Consent Agreement and are finalizing the details at the time of this submittal. The monitoring network is summarized in Table 1.
Quarterly sampling for nutrients collected by the RWS wells will be conducted at the DIW well. In addition, upon approval of this submittal, FPL shall collect grab samples from SDC-SWCCS from top, middle and bottom of the water columri as requested in the DERM July 1 Qth letter.
Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 Page 10 of 10 FPL Response to Miami Dade County L-2019-031 Enclosure 2 Page 11 of 11 The results of the monitoring efforts will be posted on the FPL database. Groundwater monitoring data demonstrate groundwater ammonia levels are and have been below the County clean-up levels for years.
Accordingly, the obligation to extract, evaluate the spatial and temporal trends for groundwater ammonia and quantify the ammonia mass removed below the clean-up target levels does not appear to be warranted.
Nonetheless, FPL agrees to the continued collection of nutrients in groundwater under the CA monitoring plan and the resulting data will be provided to MDC. Collection and reporting of ammonia data along with other nutrient data should not be construed to mean or imply that FPL agrees to conduct monitoring or remedial actions at the direction of MDC that is not consistent with or expands upon County rules and authorities. FPL is committed to work with the County to find resolutions to any disagreements that may arise in this regard.
Table 1: Consent Agreement Monitoring Network Sample Type Station Parameters Groundwater Automated data: Temperature, Specific TPGW-1, 2, 3, 4, 5, Conductance, Salinity, Water elevation (Automated 6, 7, 10, 11, 12, 13, data not collected from Land G series wells) 14, 15, 16, 17, 18, Analytic data: Cl, Na, Ca, K, S04, Tritium, TAN, 19: L-3, L-5, G-21, NH4, NH3, Nitrite plus itrate, TKN, TN, TP, and G-28 and OP, Temperature, Specific Conductivity, Salinity, pH, Dissolved Oxygen, and Turbidity Automated data: Temperature, Specific Surface Water TPSWC-1*, 2*, 3*,
Conductance, Salinity, Water elevation 4*, 5*, 7*L, 82 :
Analytic data: Cl, Na, Ca, K, S04, Tritium, TAN, TPSWlD-1*, 2*, 3*:
- NH4, H3, itrite plus Nitrate, TKN, TN, TP, TPBBSW-4, 6*, 7:
and OP, Temperature, Specific Conductivity, TPSWCCS-1 & 6 Salinity, pH, Dissolved Oxygen, and Turbidity Analytic data: TAN, NH4, NH3, Nitrite plus Water from DIW Nitrate, TKN, TN, TP, and OP, Temperature, RWS Specific Conductivity, Salinity, pH, Dissolved Oxygen, and Turbidity
- Surface water data collected at top and bottom of the water column
- 1. Replacement for TPBBSW-7B 2* Formerly TPSWTESTC-1 Frequency Hourly Quarterly Hourly Monthly Quarterly In summary, FPL will continue to work with the MDC DERM and FDEP to implement actions that address CCS ammonia contributions to groundwater and surface water outside of the FPL property consistent with our obligations under the MDC CA and FDEP CO. We are pleased to share with you the progress made by our efforts to date and look forward to continuing to work with you. As always, FPL is available to meet with you should you wish to discuss further.
Sincerely, Matthew J. Raffenberg Sr. Director of Environmental Licensing and Perrnitting CC: