Aluminium and Asbestos a planned and a non-planned waste ... · Aluminium and Asbestos - a planned...

Aluminium and Asbestos

-

a planned and a non-planned waste management task

H.-F. Beer

(former Paul Scherrer Institute )

Switzerland

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 2 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy 2017


PSI

1500 employees,

2100 guest scientists

250 MCHF

HSK-B05 Demands

on Conditioning of Radioactive Waste

H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy 2017 Seite 4 ,

(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

HSK-B05 Demands on Conditioning of

Radioactive Waste

H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy 2017 Seite 5 ,

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

Origin of Radioactive Aluminium

H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy 2017 6

SAPHIR (ca. 1 t)

DIORIT (ca. 4.2 t)

Origin of Radioactive Aluminium


Cavity, PSI-West ISOLDE-Target, CERN 260 on stock (2016) production 30 (+ 10) per year

Typical Nuclides in Aluminum-Waste average values in Bq/g

H-3 1.2E+5 Pu-239/Pu-240 <4.3E+1

Co-60 2.2E+5 Pu-238/Am-241 <3.6E+1

Ni-63 4.0E+3

Sr-90 7.5E+3

Ba-133 4.1E+2

Cs-137 1.1E+3

Eu-154 2.7E+3

Up to 50 mSv/h


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

• 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 H2O -> 2 NaAl(OH)4 + 3 H2

• 54 g 67.2 l • 1 t 1189 m3 stoichiometric*

• How to solve the problem?

*H.-F. Beer, Betrachtungen zum Druckaufbau in einem geologischen Tiefenlager für radioaktive Abfälle,

Strahlenschutzpraxis, 2015(2), p. 40-45

Aluminium conditioning


• 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.

Aluminium conditioning contd.



Pipe cutting, DIORIT

Aluminium Conditioning contd.

(inactive) Al-Tube as Melting Basket

Shielding for Transfer

SAPHIR




Al-basket

inductively coupled furnace

graphite/clay crucibles


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. 32-37


The Non-Planned Waste Management Task

Asbestos

H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy 2017

16

• Definition:

• naturally occurring fibrous silicate minerals, 1:20 in diameter to length, diameter < 0.1 µm

• Distinguished between

• serpentine asbestos – chrysotile Mg3(Si2O5)(OH)4 white, silk like, fatty

• And

• Amphiboles – amosite and crocidolite MgFe32+Fe2

3+Si8O22(OH)2 blue, rigid fibres

• 1 example

• According to their chemical composition and physical properties:

More than 95% are chrysotile

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

Asbestos


ruby.chemie.uni-freiburg.de/Vorlesung/Seminare/asbest_agp_2013.pdf

100 Å

• 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

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 - 106 fibres/(m3 year); 8 h/d, 240d/year

Limit: 0.01 fibre year exposed workers

Asbestos contd.


Suva

Asbestos contd.


No hint in the

technical drawings!

• 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!

Asbestos contd.


Asbestos contd.


Two chamber material lock

Protective clothing

H.-F. Beer, Complete Dismantling of the Research Reactor DIORIT, Strahlenschutzpraxis, 2013(2), p. 32-37

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!

How to estimate the asbestos content?

H.-F. Beer; 03/05/2017 Management of Non-Nuclear Radioactive Waste; Legnaro, Italy

2017 25

(AΣasb / Aref) x 100 = Aasb [%] Assumption: Aasb ≈ Vasb [%] Vasb/corr = f x Aasb [%], f = 0.5 (Vasb/corr x Vcont x ρasb)/100= Masb

Result: about 10 kg asbestos/container AΣasb : sum of the asbestos areas Aref : reference area Aasb : area percentage of asbestos Vasb : volume percentage of asbestos Vcont : container volume f: correction factor Masb: estimated asbestos mass [kg] ρasb: technical density of asbestos

Federal interim storage facility; BZL today


Planned for waste from medicine, industry

and research (MIR) until 2010

New plan until 2060

2015

Waiting for a final repository

Conclusion

Fulfilment of:

• Legal requirements

• Radiation protection

• Health protection

• Interim storage requirements

• Final repository requirements

• Transportation rules

• Costs


Thank you for your attention


Aluminium and Asbestos a planned and a non-planned waste ... · Aluminium and Asbestos - a planned...

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