Release and demolition of buildings and concrete structures on the Greifswald site

Transcription

1 Release and demolition of buildings and concrete structures on the Greifswald site Ronald Zimmer Eberhard Thurow Energiewerke Nord GmbH (December 2010) Page 1

2 Content 1. Strategy and boundary conditions 2. Planning approach 3. Release and demolition of buildings and concrete structures in practice (examples) 4. Masses demolished Content Page 2

3 Starting conditions Project goal: green field - Financial budget of Federal Government covered only the removal of radioactive (and chemical) contamination, i.e. no money for the conventional demolition of buildings; - The land Mecklenburg Vorpommern is responsible for the conventional demolition, but: no budget; - First planning approach included decontamination and demolition of all buildings; 1. Strategy and boundary conditions Page 3

4 Site layout and radiation protection areas of the KGR (1995) drain ditch 60 waste water injection plant waste dump waste water purification plant ZLN turbine hall unit 7/8 unit 5/6 unit 3/4 unit 1/2 ZAB ZAW ZLN - Intermediate Storage Facility North ZAW - Central Active Workshop ZAB - Intermediate Wet Storage Facility for Spent Fuel controlled areas complete monitored area planned controlled area (after erection of ZLN) contamination 0,5-5,0 Bq/cm² 1. Strategy and boundary conditions Page 4

5 Changed conditions and new strategies Project goal: brown field, i.e. using ground, infrastructure, and usable buildings for new industry; Confirmed strategies already executed in practice: - Conventional demolition of not contaminated and not needed buildings and concrete structures financed by the social agency (administrative district) and EWN; - Decontamination, clearance measurements, release (partly) of slightly contaminated buildings, and conventional use or conventional demolition; 1. Strategy and boundary conditions Page 5

6 Different discussed strategies for the demolition of contaminated buildings: Variant A: - decontamination up to a contamination level of ca. 20 Bq/cm² (Co-60); - demolition of building and storage of concrete on site (dump); - disposal/release of concrete after decay (ca. 50 years); Variant B: - decontamination up to a contamination level of ca. 20 Bq/cm² (Co-60); - keep the building (no demolition); - release/conventional demolition after decay (ca. 50 years);. Variant X: - decontamination of the Special Buildings up to a contamination level of ca. 20 Bq/cm² (Co-60); - demolition of buildings; - decay storage of concrete in the reactor buildings units 1-4; (Investigations of different strategies were performed by an external engineering company.) 1. Strategy and boundary conditions Page 6

7 At present favoured planning variants: - decontamination of the Reactor Buildings 1-4 and the three Special Buildings up to a contamination level of ca. 20 Bq/cm² (Co-60); - keep the building (no demolition); - release/conventional demolition after decay (ca. 50 years); 1. Strategy and boundary conditions Page 7

8 Planned masses for dismantling and demolition Overall site inventory KGR Mg Radiologically unrestricted material (buildings and facilities) Mg Other radioactive residuals Mg Remaining building structures for free classing Mg Concrete as radioactive waste or for decay storage Mg Dismantled plant parts Mg Package production, sorting according to material and radiology Air locks, buffer storages, treatment stations Unrestricted release (Class A) Mg Restricted reuse and utilization (Class B) Mg Disposal as conventional waste (Class C) Mg Decay storage (Class D) Mg Controlled reuse and utilization in nuclear facilities (Class E) Mg Disposal as radioactive waste (Class F) Mg 2. Planning approach (ca ) Page 8

9 Planned masses generated by the decontamination of buildings Based on : - the operational history, - first concrete investigations, - experience from other decommissioning projects, a rough estimation of the masses generated by the decontamination of floors was performed. Total floor surface of the buildings: - Reactor Buildings 1-5, - Special Buildings 1, 2, 3, - Wet Spent Fuel Storage, Σ ~ m² Concrete depth to be removed: Density of concrete: Mass to be removed: 5 cm 2.6 g/cm³ ~ Mg 2. Planning approach (ca ) Page 9

10 Building categorisation The contamination category of buildings depends on the possible contamination paths and thus on the categorisation of the systems. Following some examples of already demolished, partly demolished or planned demolitions of buildings or building structures: Not contaminated buildings: - additional feed water treatment plant (only reactor building) - emergency diesel generator buildings (units 1/2, 3/4, 5/6) - water power plant (between the open outlet cooling channel and the Greifswald bay) 2. Planning approach Page 10

11 Building categorisation Potentially contaminated buildings: - closed outlet cooling channels (units 1-6) - turbine hall units 1-6 Contaminated buildings: - turbine hall units 1-4 (partly contaminated) - sanitary laboratory building 1 (partly contaminated) - closed piping channel (from the wet spent fuel storage to the common special building) - wet spent fuel storage (ZAB) 2. Planning approach Page 11

12 Not contaminated buildings Additional feed water treatment plant (reactor building) Check absence of contamination: Spot checks (category I) Used technique for demolition: Explosion Masses of demolished material: Mg Page 12

13 Demolition of the additional feed water treatment plant (only reactor building) Page 13

14 Not contaminated buildings Emergency diesel generator buildings units 1/2 and 3/4 Check absence of contamination: - investigation of building according the instruction for not contaminated material - category I (spot checks); - exceeded guide values on the roof and on the supply air system (only section 2 - diesel 1/2); - disposal of these material as category II/III material; Used technique for measurements: - free release measurement facility for category II/III material Used technique for demolition: - excavator with hydraulic hammer Masses of demolished material: - units 1/2: Mg - units 3/4: Mg Page 14

15 Demolition of emergency diesel generator buildings unit 1/2 and 3/4 Page 15

16 Not contaminated buildings Water power plant Check absence of contamination: spot checks (category I) Used technique for demolition : excavator with hydraulic hammer Masses of demolished material: Mg Page 16

17 Demolition of the water power plant (4 water turbines with in total 14 MW el ) Page 17

18 Potential contaminated buildings Closed outlet cooling channels (units 1-6) Check absence of contamination and used measurement technique: - special measurement procedure: - removal of sludge and measurement with the free release facility, - sampling by core drilling device (trepanning) and gammaspectrometric evaluation of cylindrical concrete samples, - free release with in-situ-gamma spectrometric measurement. Used technique for demolition : - excavator with hydraulic hammer Masses of demolished material: Mg (total mass for 8 units) Page 18

19 Demolition of the outlet cooling channel (units 1-6) Page 19

20 Potentially contaminated buildings Turbine hall units 1-6 Check absence of contamination and used measurement technique: - spot checks (category I), - special measurement procedure (category II): - sampling by core drilling device (trepanning) and gammaspectrometric evaluation of cylindrical concrete samples, - free release with in-situ-gamma spectrometric measurement. (Unrestricted release of turbine hall only up to the floor plate (without floor plate); Request of authority: - no sale, only rental of turbine hall) Used technique for part demolition: - excavator with hydraulic hammer e.g. turbine desks, 0 m level ceiling, walls; (the building corpus was not demolished) Masses of demolished material: Mg (categories I/II/III) Page 20

21 Contaminated buildings Turbine hall units 1-4 (partly contaminated) Check absence of contamination and used measurement technique: - special measurement procedure (category III): - sampling by core drilling device (trepanning) and gammaspectrometric evaluation of cylindrical concrete samples, - free release with in-situ-gamma spectrometric measurement. (Unrestricted release of turbine hall only up to the floor plate (without floor plate); Request of authority: - no sale, only rental of turbine hall) Used technique for decontamination and partly demolition: - partly decontamination of walls (pillar line B) e.g. with air hammer, - excavator with hydraulic hammer e.g. rail corridor (0 m level), partly m floor (the building corpus was not demolished) Masses of demolished material: Mg (category III) Page 21

22 Partly demolition of the turbine hall units 1-6 Radiological investigation sump (-3.6 m) unit 4 Page 22

23 Contaminated buildings Sanitary laboratory building 1 (partly contaminated) Check absence of contamination and used measurement technique: - spot checks (category I), - special measurement procedure (category II/III): - sampling by core drilling device (trepanning) and gammaspectrometric evaluation of cylindrical concrete samples, - free release with total beta measurement device. (The used release limit value require the building demolition - restricted release.) Used technique for demolition ( ): - excavator with hydraulic hammer Masses of demolished material: Mg (categories II/III) Page 23

24 Decontamination of the sanitary laboratory building 1 Page 24

25 Contaminated buildings Closed piping channel (from the wet spent fuel storage to the common special building) Check absence of contamination and used measurement technique: - special measurement procedure (category III): - sampling by core drilling device (trepanning) and gammaspectrometric evaluation of cylindrical concrete samples, - free release with in-situ-gamma spectrometric measurement. Used technique for demolition (2008): - excavator with hydraulic hammer Masses of demolished material: Mg (category III) Page 25

26 Piping channel (from the wet spent fuel storage to the common special building) Free release measurement with the in-situ-gamma spectrometry measurement device Page 26

27 Contaminated buildings Wet spent fuel storage Check absence of contamination and used measurement technique: - spot checks (category I), - special measurement procedure (category II/III): - sampling by core drilling device (trepanning) and gammaspectrometric evaluation of cylindrical concrete samples, - free release with total beta measurement device. (The used release limit value require the building demolition - restricted release.) Used technique for demolition ( ): - excavator with hydraulic hammer Masses of material to be demolished: Mg (categories II/III) Page 27

28 Wet spent fuel storage Page 28

29 Wet spent fuel storage Laser cutting Page 29

30 demolished objects - category I (reinforced concrete and bricks) mass [Mg] turbine hall units 1-6 (parts inside) ,00 turbine hall units 7/8 (parts inside) ,00 halls and stores ,00 unload station for oil 40,00 transformers of turbines ,00 waste water injection plant 4.180,00 emergency power supply building I 9.440,00 (diesel generators) emergency power supply building II 8.540,00 (diesel generators) waste water purification plant 2.330,00 railway sleepers 1.650,00 relay building 960,00 physical protection walls, checkpoints 9.000,00 pump station for demineralisated water 1.180,00 neutralisation plant 3.200,00 workshop of the water power station 780,00 water power plant ,00 open cooling channel ,00 closed cooling channels ,00 control room building extension unit ,00 stair well unit ,00 others ,00 total mass ,00 4. Masses demolished (till June 2008) Page 30

31 demolished objects - category I (reinforced concrete and bricks) mass [Mg] emergency power supply building III ,00 wet spent fuel storage ,00 sanitary laboratory building ,00 closed piping channel 1.050,00 (from the wet spent fuel storage to the common special building) stair well of the warm workshop 880,00 barrier/wall (physical protection) 560,00 hall (of the old demineralisation station) 530,00 pipe bridges 2.740,00 others ,00 total mass ,00 masses since ,00 4. Masses demolished (from July 2008 till December 2010) Page 31

32 Release and demolition of buildings and concrete structures on the Greifswald site END Page 32

33 BAW 24/95 (operational instruction for category I material) guide value for material: Co Bq/g 0.1 Bq/cm² Used measurement techniques: - total beta contamination monitor - wipe tests - material samples - scrape tests Page 33