Aluminium and Asbestos - a planned and a non-planned waste management task

Transcription

1 Aluminium and Asbestos - a planned and a non-planned waste management task H.-F. Beer (former Paul Scherrer Institute ) Switzerland

2 Contents Short introduction to PSI Demands on waste conditioning in Switzerland Origin of radioactive aluminium Properties and demands Solution Asbestos (in radioactive waste) Description Hazards Origin Solution Conclusion H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

3 PSI 1500 employees, 2100 guest scientists 250 MCHF H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

4 HSK-B05 Demands on Conditioning of Radioactive Waste (Former R-14) Demands on waste packages and conditioning procedures - Description of waste packages and its components - Description of the contents - Documentation - Quality Assurance Approval of waste packages and conditioning procedures - Approval of waste package types - Approval of single waste packages - Transfer application into the surveillance of ENSI, H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy 2017 Seite 4

5 HSK-B05 Demands on Conditioning of Radioactive Waste physical properties: solid or solidified minimum compressive strength of 10 MPa The leaching rate must be well below the statuary value of 5 m/d stable in water and gypsum-water Consequence: solidified with or embedded in Cement/concrete glass/slag, H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy 2017 Seite 5

6 Origin of Radioactive Aluminium SAPHIR (ca. 1 t) DIORIT (ca. 4.2 t) H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

7 Origin of Radioactive Aluminium Cavity, PSI-West ISOLDE-Target, CERN 260 on stock (2016) production 30 (+ 10) per year H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

8 Typical Nuclides in Aluminum-Waste average values in Bq/g H-3 1.2E+5 Pu-239/Pu-240 <4.3E+1 Co E+5 Pu-238/Am-241 <3.6E+1 Ni E+3 Sr E+3 Ba E+2 Cs E+3 Eu E+3 Up to 50 msv/h H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

9 Treatment Options decontamination followed by free release for unrestricted use treating methods, f. i. ultra sonic bath weakly activated materials: storage for decay within 15a/30a followed by free release conditioning for final disposal melting furnace, embedding in concrete H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

10 Aluminium conditioning Demands: - Solidified and/or embedded the Al waste in cement mortar - No or reduced gas production Problem: - Dissolution of aluminium in aqueous alkali liquid mortar 2 Al + 2 NaOH + 6 H 2 O -> 2 NaAl(OH) H 2 54 g 67.2 l 1 t 1189 m 3 stoichiometric* How to solve the problem? *H.-F. Beer, Betrachtungen zum Druckaufbau in einem geologischen Tiefenlager für radioaktive Abfälle, Strahlenschutzpraxis, 2015(2), p H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

11 Aluminium conditioning contd. The problem was solved by cutting the Al-waste into pieces of 20 x 120 cm size Place the pieces in Al-baskets of Ø28 x 130 cm. Melting the Al-baskets with the Al-waste in inductively coupled furnace into graphite/clay crucibles. Placing the crucibles with the melted Al-waste in a concrete container. And embedding the crucibles in PSI-mortar. Result: Reduced reactive surface of the Al in contact with the mortar with a slightly gas evolution before hardening of the mortar. After hardening no gas formation can be observed! Accepted by NAGRA for final disposal. Approved by the authority. H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

12 Aluminium Conditioning contd. Pipe cutting, DIORIT H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

13 (inactive) Al-Tube as Melting Basket Shielding for Transfer SAPHIR H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

14 Aluminium Conditioning contd. Al-basket inductively coupled furnace graphite/clay crucibles H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

15 Aluminium Conditioning contd. Crucibles filled with Al and placed in a PSI concrete container H.-F. Beer, Complete Dismantling of the Research Reactor DIORIT, Strahlenschutzpraxis, 2013(2), p H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

16 The Non-Planned Waste Management Task Asbestos H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

17 Asbestos Definition: naturally occurring fibrous silicate minerals, 1:20 in diameter to length, diameter < 0.1 µm Distinguished between serpentine asbestos chrysotile Mg 3 (Si 2 O 5 )(OH) 4 white, silk like, fatty And Amphiboles amosite and crocidolite MgFe 3 2+ Fe 2 3+ Si 8 O 22 (OH) 2 blue, rigid fibres 1 example According to their chemical composition and physical properties: More than 95% are chrysotile H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

18 Asbestos Chrysotile structure: Silicate tetrahedrons and brucite octahedrons brucite: Mg(OH) 2 Lattice parameter in silicate is smaller than in brucite result is a snake like spiral cross section 100 Å ruby.chemie.uni-freiburg.de/vorlesung/seminare/asbest_agp_2013.pdf H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

19 Asbestos contd. Sever health hazard! Asbestosis, fibrotic lung disease, after long and intense exposure to asbestos, short breath, reduced lung capacity Lung cancer, cancer in the mesothelium, latency of 20 to 60 years H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

20 Asbestos contd. In whole European Community forbidden since 2005 In Switzerland generally forbidden in 1990, With a stepwise reduction of its use until 1994 Exposure Regulation: fibre years fibres/(m 3 year); 8 h/d, 240d/year Limit: 0.01 fibre year exposed workers Suva H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

21 Asbestos contd. No hint in the technical drawings! H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

22 Asbestos contd. What to do? - The work was interrupted immediately, - The authority for conventional safety (Suva) was informed, - The personnel involved was medically checked and their probable asbestos exposure was estimated by experts, - The building was checked for asbestos and cleaned up by a specialized company, - After the cleaning, the building was checked for asbestos again and proved to be clean, - The necessary installation to work with non fixed asbestos fibers (black zone) was implemented, - A two chamber air lock for material was installed, - A four chamber lock for the personnel was installed, - The air-ventilation was changed to separate the reactor hall from the other rooms in the building, - The people working in the asbestos zone wear a whole-body overall with a protection mask and an electrically operated and filtered air supply, - The responsible personnel has been trained as asbestos specialists, - Guideline EKAS 6503! H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

23 Asbestos contd. Two chamber material lock Protective clothing H.-F. Beer, Complete Dismantling of the Research Reactor DIORIT, Strahlenschutzpraxis, 2013(2), p H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

24 Asbestos contd. four-chamber lock for the personnel It is a health protection problem and not a waste conditioning problem. The absolute quantity is very small. After being fixed, asbestos can be safely embedded in mortar. About 10 kg per 15 tonnes, about 0.7 asbestos in a waste container! H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

25 How to estimate the asbestos content? (A Σasb / A ref ) x 100 = A asb [%] Assumption: A asb V asb [%] V asb/corr = f x A asb [%], f = 0.5 (V asb/corr x V cont x ρ asb )/100= M asb Result: about 10 kg asbestos/container A Σasb : sum of the asbestos areas A ref : reference area A asb : area percentage of asbestos V asb : volume percentage of asbestos V cont : container volume f: correction factor M asb : estimated asbestos mass [kg] ρ asb : technical density of asbestos H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

26 Federal interim storage facility; BZL today 2015 Waiting for a final repository Planned for waste from medicine, industry and research (MIR) until 2010 New plan until 2060 H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

27 Conclusion Fulfilment of: Legal requirements Radiation protection Health protection Interim storage requirements Final repository requirements Transportation rules Costs H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

28 Thank you for your attention H.-F. Beer; 03/05/ Management of Non-Nuclear Radioactive Waste; Legnaro, Italy 2017