Protection of Radiation and Waste Treatment

JUTTI LEVITA-FACULTY OF PHARMACY-UNIVERSITAS PADJADJARAN

PROTECTION OF RADIATION

AND

RADIOACTIVE WASTE TREATMENT

SYMBOLS

Pengendalian Daerah Kerja

Bidang Keselamatan – Pusat Radioisotop dan Radiofarmaka

Explosive (E) Toxic (T)

Harmful (Xn)

Harmful (Xn)

Caution

Biohazard Radiation Ionizing Radiation

http://en.wikipedia.org/wiki/Image:Skull_and_crossbones.svg

http://upload.wikimedia.org/wikipedia/commons/b/bb/Hazard_E.svg



Optical Radiation

Non Ionizing Radiation

Laser Radiation

High Voltage

Chemical Weapon Corrosive Highly Flammable (F)





Extremely

Flammable (F+)

Dangerous for the

Environmental

Oxidizing Agent (O) Very Toxic (T+)



Harmful (Xn) Irritant (Xi) Chemical Hazard


Radiation Absorbed Dose The absorbed dose characterized the amount of damage done to the

matter (especially living tissues) by ionizing radiation. The absorbed

dose is more closely related to the amount of energy deposited.

The SI unit of absorbed dose is the gray (Gy) (or J/kg).

1 Gy = the amount of radiation required to deposit 1 joule of energy in 1

kilogram of any kind of matter.

The sievert (Sv) is the SI derived unit of equivalent radiation dose, effective

dose, and committed dose.

1 Sv = the amount of radiation necessary to produce the same effect on

living tissue as 1 Gy of high-penetration x-rays.

Quantities that are measured in Sv are designed to represent the biological

effects of ionizing radiation.

Radioactive Contamination

Kontaminasi radioaktif terjadi apabila larutan atau serbuk radioaktif tertumpah ke lantai, mengenai baju atau bagian tubuh, atau terdispersi ke udara dan terhirup melalui inhalasi.

Faktor-faktor yang harus diperhatikan pada pengukuran kontaminasi adalah:

• Level kontaminasi

• Identifikasi kontaminan

• Sifat permukaan bahan yang terkontaminasi

Exposure of Radiation

The amount of exposure of external radiation could be monitored using a dosimeter.

The amount of exposure of internal radiation could be calculated indirectly by measuring the radioactivity in urine or faeces.

http://www.degmark.com/products/dosimeter

http://www.degmark.com/products/dosimeter

Metode pemantauan kontaminasi:

• Survey method

Metode survey

dilakukan dengan cara

men-scan permukaan

yang terkontaminasi

menggunakan alat

survey meter

• Smear method (metode

usap)

Metode usap dilakukan

dengan cara mengusap

daerah kontaminan

dengan cotton,

kemudian ditempatkan

pada plan set, dan

diukur tingkat

kontaminasinya



Survey method Mapping the contamination area

Monitoring Decontamination



Smear method

Mekanisme kerja survey meter adalah sebagai berikut:

Ionization chamber survey meter

Survey meter ini terdiri dari tabung

tertutup berisi gas inert Ar atau He dan dua elektroda.

Kontaminan radioaktif mengemisikan radiasi pengion dan tertangkap oleh detektor survey meter.

Radiasi pengion akan mengionisasi atom gas inert di dalam tabung detektor, ion positif bergerak menuju katoda dan ion negatif menuju anoda, menyebabkan arus mengalir dan terukur ekivalen dengan dosis radiasi kontaminan.

Surveymeter ß/ IC

• Geiger Muller survey meter

Survey meter ini merupakan detektor

radiasi terdiri dari tabung tertutup berisi

gas inert Ar, Ne, atau He dengan halogen

ditambahkan di dalamnya, serta dua

elektroda.

Kontaminan radioaktif mengemisikan

radiasi pengion dan tertangkap oleh

detektor survey meter.

Radiasi pengion tersebut akan

mengionisasi atom gas inert di dalam

tabung detektor, ion positif bergerak

menuju katoda dan ion negatif menuju

anoda, menyebabkan arus mengalir dan

terukur setara dengan dosis radiasi

kontaminasi. Surveymeter ß/ GM

Bila inti memiliki nilai N/Z berbeda dengan nilai N/Z inti stabil, maka inti atom tersebut tidak stabil dan akan mengalami peluruhan (decay) dengan memancarkan partikel b atau melalui tangkapan elektron

Atomic Symbols • A = mass number = protons + neutrons

• Z = atomic number = protons = electrons

A – Z = the number of neutrons

XA

Z

XA

Z XA

Z XA

Z

XA

Z Na23

11

α decay

The reason alpha decay occurs is because the nucleus has too

many protons which cause excessive repulsion. In an attempt to

reduce the repulsion, a Helium nucleus is emitted.

An example of this is a uranium-238 atom decaying into into a thorium-234 atom and an alpha particle (helium-4 nucleus, i.e. 2 protons and 2 neutrons).

U 235 92 Th 231

90 + He 4

2

Example of beta decay is an atom of carbon-15 changing into

an atom of nitrogen-15 by emitting an electron.

Notice that the number of particles in the nucleus have stayed

the same; 15 in each case [A does not change].

β decay


Positron Decay of Carbon-11 to Boron-11

β+ decay

Here's a diagram of electron capture with beryllium-7:

11C → 11B + e+ + νe + 0.45 MeV


γ decay

10 mL

Pengukuran radioaktivitas larutan menggunakan Dose

Calibrator

Whole vial assay method 500 mCi

Aliquot method

1 mL Syringe Sisa tertinggal dalam needle 1 mL Eluate

= 53 mCi = 3 mCi = 50 mCi

Aktivitas Total 50 mCi/mL x 10 mL = 500 mCi



Contains small concentration of radionuclides

Does not require radiation protection

Contains short T1/2 of radionuclides

Activity concentration > clearance level

Should be stored until activity decreases

Contains short T1/2 of radionuclides

Activity concentration is in the region of

clearance level

Requires radiation protection

Activity concentration > clearance level

Does not require shielding during handling

Does not require determining factor for long term safety

Contains long-lived radionuclides

Activity concentration is high

Should be isolated from the biosphere

Disposal should be in the range of hundred meters depth

Contains very high activity concentration of short and long-lived radionuclides

Disposal should be very deep with engineered barrier










Radionuclide Production


1. Cyclotrons

• Cyclotrons produce radionuclides by bombarding stable nuclei with high-energy charged particles

• Most cyclotron-produced radionuclides are neutron poor and therefore decay by positron emission or electron capture

• Specialized hospital-based cyclotrons have been developed to produce positron-emitting radionuclides for positron emission tomography (PET) – Usually located near the PET imager because of short half-

lives of the radionuclides produced

Magnet 1

Magnet 2

Dee 1

Dee 2

Vacuum Sumber ion

Side view

~

Hollow Electrodes (Dees)

Oscillator

Target

Deflector

Top view https://www.youtube.com/watch?v=M_jIcDOkTAY

https://www.youtube.com/watch?v=cNnNM2ZqIsc

https://www.youtube.com/watch?v=M_jIcDOkTAY



2. Nuclear Reactors

• Specialized nuclear reactors used to produce clinically useful radionuclides from fission products or neutron activation of stable target material

• Uranium-235 fission products can be chemically separated from other fission products with essentially no stable isotopes (carrier) of the radionuclide present

• Concentration of these “carrier-free” fission-produced radionuclides is very high

https://www.youtube.com/watch?v=1U6Nzcv9Vws



Contoh:

Ketika 235U mengabsorpsi neutron, inti atom akan mengalami reaksi fisi dan pecah menjadi dua atau lebih produk fisi berupa nuklei yang lebih ringan, dengan melepaskan energi kinetik, radiasi gamma, dan neutron bebas.

Neutron bebas tersebut selanjutnya akan diabsorpsi oleh atom lain, dan memicu reaksi fisi berikutnya.

../e-Learning/Fission Reaction.flv

Neutron Activation

• Neutrons produced by the fission of uranium in a nuclear reactor can be used to create radionuclides by bombarding stable target material placed in the reactor

• Process involves capture of neutrons by stable nuclei

• Almost all radionuclides produced by neutron activation decay by beta-minus particle emission

3. Radionuclide Generators

• Technetium-99m has been the most important radionuclide used in nuclear medicine

• Short half-life (6 hours) makes it impractical to store even a weekly supply

• Supply problem overcome by obtaining parent Mo-99, which has a longer half-life (67 hours) and continually produces Tc-99m

• A system for holding the parent in such a way that the daughter can be easily separated for clinical use is called a radionuclide generator

• Kolom gelas berisi adsorben alumina sebagai media penyangga untuk radionuklida induk 99Mo dalam bentuk molibdat. Radionuklida induk akan terikat kuat pada media penyangga dan tidak terlepas pada elusi radionuklida anak 99mTc pertehnetat.

• Sistem tabung dirancang agar kolom dapat dialiri larutan saline (NaCl) steril, karena radionuklida yang dihasilkan, yaitu 99mTcO4- dalam larutan NaCl, dapat langsung digunakan untuk injeksi.

• Sistem filter pada generator ini terbuat dari cakram gelas dengan ukuran pori-pori 0,22 μm, yang fungsinya untuk menghilangkan partikel-partikel kecil dari larutan elusi dan menjamin sterilitas produk.

Documents

Protection of Radiation and Waste Treatment