Unit 1. Workshop - BHWP. Experts Teaching from Practical Experience

Transcription

1 Unit 1 Workshop - BHWP Experts Teaching from Practical Experience

2 Bruce Heavy Water Plant (BHWP) Owned & operated by Ontario Power Generation, located on the Bruce Nuclear site near the shore of Lake Huron Original plans called for four individual Heavy Water Plants, each consisting of: 2 Enrichment Units, and 1 Finishing Unit Kinectrics Inc

3 Bruce Heavy Water Plant (BHWP) Produced heavy water beginning in 1973 and ending in 1997 Used steam generated by Douglas Point, Bruce NGS A or an oiled fired steam plant Did not use or generate any radioactive materials but did use hazardous materials (H2S, asbestos insulation, etc) Kinectrics Inc

4 Geib Spevack (GS) Process Also know as the Grindler-Sulphide Process. An Enriching Unit consists of pairs of sieve tray columns; a cold tower maintained at 30 C and a hot tower maintained at 130 C. Hydrogen sulfide gas is circulated in a closed loop between the cold tower and the hot tower. Demineralised water is fed to the cold tower where deuterium migration preferentially takes place from the hydrogen sulfide gas to the liquid water. This "enriched" water from the cold tower is fed to the hot tower where the deuterium migrates from the liquid water to the hydrogen sulfide gas. Kinectrics Inc

5 Geib Spevack (GS) Process A "cascade accomplishes enrichment. Normally, water is enriched to 15 20% deuterium. Further enrichment to "reactor-grade" heavy water (> 99% deuterium) is done by vacuum distillation in the Finishing Unit. Required 340,000 tonnes of feed water to produce one tonne of heavy water Kinectrics Inc

6 History Heavy Water Plant A Operated from 1973 to 1984 Placed in a safe state (hydrogen sulphide transferred to storage) in 1984 Most structures demolished during Heavy Water Plant B Operated from 1979 to 1997 Enriching Unit E3 shutdown in 1993 and demolished in 1995 Enriching Unit E4 shutdown due to steam supply problem on May 1, 1997 and never restarted Kinectrics Inc

7 History Heavy Water Plant C Operation Building C and foundations for Enriching Units E5 & E6 were constructed No other above ground structures were built and no underground utility lines were installed Heavy Water Plant D Plant D was cancelled when 70% complete Above ground structures of Enriching Unit E8 were demolished in 1995 Facilities in Finishing Unit F4 are used to handle & store heavy water Kinectrics Inc

8 History Decision to permanently shutdown BHWP was made on Aug. 30, 1997 CNSC & MoE approved the disposal of the hydrogen sulphide inventory by controlled flaring, Mg of H2S were flared between Nov. 6, 1997 and Jan. 23, 1998 (approximately 1 Mg of H2S remained in plant systems) All plant systems sweetened and verified by Mar. 31, 1998, all other process chemicals removed from site Utilities and services to shutdown systems were isolated (physically cut) in 2001 Utilities and services required for continuing operations were isolated from the shutdown systems (required the reconfiguration of some piping and electrical lines) Kinectrics Inc

9 History Some decommissioning work was completed prior to 2000 (before the Nuclear Safety & Control Act) The following facilities were demolished: Heavy Water Plant A, Enriching Unit E4 Enriching Unit E8 Kinectrics Inc

10 Licensing Heavy Water Plant Operating License, includes Heavy Water Plant B excluding E3 pad, Common Services Area (Supply & Return Channel, pump houses, H2S storage area, North Flare Stack, Surface Water Treatment Facility, East & West Effluent Lagoons, etc) Drum Filling Building (originally part of Heavy Water Plant A) Heavy Water Storage Area in Operations Building D (intended to be part of Heavy Water Plant D) Heavy Water Plant D Construction Approval Includes partially constructed E8 and pad from the demolished E7 Part of the BHWP is located within the Exclusion Zone for Bruce NGS B Kinectrics Inc

11 Licensed Area Size of the licensed areas was reduced following completion of the demolition work performed in Kinectrics Inc

12 Licensing Water-hydrogen sulphide exchange towers, compressors & blowers and infrared absorption analyzer (in the laboratory) are controlled nuclear equipment under the Nuclear Non- Proliferation Import and Export Control Regulations Bruce Power held a consolidated Certificate of Approval for the BP site discharge of water from the Surface Water Treatment Facility to the lake was the only regulated discharge relevant to the project OPG was registered as a generator of hazardous wastes OPG held a permit to remove bird nests from BHWP structures (required under the Canadian Migratory Bird Act) Kinectrics Inc

13 Scope of the Decommissioning Some parts of the BHWP Site were excluded from the scope of the Decommissioning Project: Old Steam Plant Condensate Plant Steam Transformer Plant O Standby Generators Kinectrics Inc

14 Scope of the Decommissioning Explicitly identified whether each building on the BHWP site was: intended for demolition or retention within the limits of either the HWP Operating License or Construction License within the limits of the Bruce NGS B Exclusion Zone Kinectrics Inc

15 Objectives Make the site available for future power generation activities (owned by OPG but leased to Bruce Power) Retain heavy water storage & handling facilities in Operations Buildings B & D for future use (heavy water to be stored under a Nuclear Substances License) Retain Cooling Water intake & outfall for possible future use Permit continued operation of the laboratory (used by Bruce Power) throughout the course of the decommissioning work Recover stainless steel for recycling (proceeds used to partially finance the decommissioning work) Kinectrics Inc

16 Initial State Structures & Systems All production facilities in safe shutdown state Heavy water (a non-radioactive nuclear substance) stored in Operations Buildings B & D, other areas of these buildings used as office space Laboratory Building in routine use Utilities and services to shutdown systems isolated (physically cut) Stagnant water standing in Surface Water Treatment Facility Kinectrics Inc

17 Initial State Hazardous Materials Some asbestos insulation Freon (Ozone Depleting Substance) in room air conditioners PCBs in some transformers Lead solder & paints in most buildings Mercury in fluorescent lights & thermostats Kinectrics Inc

18 Initial State Radiological Contamination The only radioactive materials on the site were metallic uranium foils for the infrared absorption analyzer in the Laboratory Heavy water (a non-radioactive nuclear substance) stored in Operations Buildings B & D Industrial radiography sources formerly stored in a building south of Enriching Unit E1 had been removed Steam used in the process did occasionally contain low levels of tritium (prior to construction of Steam Transformer Plants) Two radioactive particles (both < 1 kbq of cobalt-60) were discovered and removed during a site contamination survey conducted in 2000 Kinectrics Inc

19 Site Contamination Survey The contamination surveys were performed using four 5x5 NaI detectors mounted on the rear bumper of a vehicle. A GPS receiver was also mounted on the vehicle. Data from both the NaI Detectors and the GPS were recorded by a laptop in the vehicle and downloaded to a Geographical Information System (GIS) for processing. Kinectrics Inc

20 Initial State Non-Radiological Contamination - Soil Metals (154 samples collected) 14 samples were found to exceed at least one guideline values (35 distinct exceedences, 11 samples with more than 1 exceedence) 8 surface samples with 25 exceedences (rust coloured stainming was observed on the surface where these samples were collected) zinc (7), nickel (6) and copper (5) were most common exceedences 6 subsurface samples with 10 exceedences copper (4) and boron (3) were most common exceedences Petroleum (182 samples collected) 34 samples were found to exceed the guideline value Kinectrics Inc

21 Contaminated Areas Diagram showing distribution and levels of petroleum contamination in soil Kinectrics Inc

22 Contaminated Areas Contamination was generally limited to the near surface soils - metals were generally limited to the top 10 cm - petroleum was generally limited to the top 1.5 meters Kinectrics Inc

23 Initial State Non-Radiological Contamination - Groundwater Single set of samples collected from 31 wells (7 upstream, 8 within and 16 downstream of BHWP site) and analyzed for metals, PCBs, VOCs and BTEX Selenium in excess of the guideline value was measured in one downstream well, selenium below the guideline value was also observed in one well upstream and one well within the BHWP site Arsenic below the guideline value was observed in one well upstream, two wells within and one well downstream of the BHWP site Antimony below the guideline value was observed in one well upstream, one well within and one well downstream of the BHWP site No other groundwater contaminants were detected Kinectrics Inc

24 End State Designated structures and systems demolished to grade level All radioactive materials (except uranium foils) and contamination, hazardous process chemicals and demolition debris removed from site Soil contamination remediated to levels (industrial use, non-potable water) specified by MoE Guidelines for Use at Contaminated Sites in Ontario Heavy Water will continue to be stored in Operations Buildings B & D under a Nuclear Substances License Remainder of site available for future power generation activities Kinectrics Inc

25 Decommissioning License Phase II Environmental Site Assessment conducted following the closure of the BHWP Detailed Decommissioning Plan prepared by a consultant Submitted December 2001 & revised May 2002 Environmental Assessment (Comprehensive Study) conducted Technical studies performed by OPG beginning in June 1998 EA approved by the Minister of the Environment in November 2003 Public Hearing was held on February 4, 2004 Kinectrics Inc

26 Decommissioning License Decommissioning License Issued March 12, 2004 License is valid until March 31, 2014 Commission requested that CNSC staff present interim status reports after two years and five years A demolition firm was retained to conduct the decommissioning A Construction Island was created OPG was responsible for nuclear safety within the Construction Island Demolition firm was the constructor and responsible for obtaining the necessary Building Permits Demolition work performed Kinectrics Inc

27 BHWP Tower Removal Towers were removed by: building a sand berm, toppling the towers onto the berm, breaking up and removing the debris recovered material was recycled wherever possible. Kinectrics Inc

28 BHWP Tower Removal Kinectrics Inc

29 BHWP Tower Removal Kinectrics Inc

30 BHWP Tower Removal Kinectrics Inc

31 BHWP Decommissioning Kinectrics Inc

32 BHWP Decommissioning Kinectrics Inc

33 BHWP Decommissioning Approximately 97% of the materials arising from the demolition was recycled Proceeds of recycling subsidized the cost of decommissioning No equipment was recovered for reuse Costs of recovery were prohibitive due to labour relations issues Soil contamination was remediated to the levels required by the MoE Guidelines for Use at Contaminated Sites in Ontario (industrial use, non-potable water) Environmental monitoring conduced prior to, and during dismantling indicate no adverse environmental impacts OPG is conducting the end state monitoring ( ) and will obtain the License to Abandon Kinectrics Inc

34 End State Monitoring End State monitoring was prescribed by the CNSC when the Commission accepted the Environmental Assessment for the decommissioning (March 2003) Radiation surveys Soil Sampling Groundwater Monitoring The standards (MoE 1997) prescribed for the Follow-up Monitoring have been superceded Kinectrics Inc

35 End State Monitoring Kinectrics Inc

36 End State Monitoring Kinectrics Inc

37 Ontario MoE Soil, Sediment and Water Standards Soil, Ground Water and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act, Ministry of the Environment, July 27, 2009 Kinectrics Inc

38 Ontario MoE Soil, Sediment and Water Standards Soil, Ground Water and Sediment Standards for Use Under Part XV.1 of the Environmental Protection Act, Ministry of the Environment, July 27, 2009 Kinectrics Inc