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EM Shielding, Dosimetry Control and

Xe(135)-Sm(149) Poisoning Effect for

Nuclear Waste Treatment

Syed Bahauddin Alam1,

Hussain Mohammed Dipu Kabir, Md. Nazmus Sakib, Celia Shahnaz, Shaikh Anowarul FattahDepartment of EEE, Bangladesh University of Engineering and Technology, Dhaka

1baha [email protected]

Abstract—A crucial yard mensuration of the shape up of a state is the level to which clean, low-priced and sustainableenergy resources are made available for the bulk assemblage.At present eons, equating cost factors, environmental issues,power generation with other substitute energy informants,atomic or nuclear power is turning into a popular alternative

as an energy option. Though it is clean and safe alternative,nuclear waste is still a matter of great concern. In this paper,nuclear waste treatment for nuclear plant by radioactiveand electromagnetic shielding via dose conversion factors,photons and neutrons response functions has been explained.Moreover, analyzing of Quality-Factor and Poisoning decayof Xenon and Samarium has been discussed. In this papermodernized radioactive waste treatment processes as wellas secured data transmission from nuclear power plantto National Load Dispatch Center (NLDC) using digitalwatermarking is proposed as this type of vulnerable datatransmission is a matter of great concern.

Index Terms—EM (Electromagnetic) shielding, dose,kerma, Quality-Factor, poisoning, Samarium, Xenon, digitalwatermarking.

I. INTRODUCTION

The promising conveyable of nuclear waste materials

from nuclear reactors and defense amenities to a repository

are the essence concern in the present eon. The aspiration

of waste treatment is of grave importance now in order

to handle nuclear waste transportation issues at the local,

tribal, state, regional and national levels [1]. For fossil fuel

burning power plants, solid waste is primarily a trouble

for coal based power generation. Approximately 10% of

the substances of coal is ash which often includes metal

oxides and alkali. Such residues necessitate disposition,

generally burial, though some reprocessing is possible, in amanner that limits migration into the general environment.

Volumes can be substantive. While burning in a power

plant, oil also yields residues that are not entirely burned

and thus conglomerate [2], [3]. These residuals must also be

disposed as solid wastes. Once the fission operation in the

reactor has decelerated, the fuel rods are supplanted. The

spent fuel rods hold extremely radioactive fission products

and must be stored safely [4], [5].

These used fuel rods are regarded as high level nuclear

waste. Currently all high level nuclear waste is stored in

large pools of water at the power plants where it was

generated [6]. Seven to ten feet of water is enough to stop

all radioactivities. Since the late 1950’s, high level nuclear

waste has been stored in this form, and there has never been

any release of radioactivity. There is actually a relatively

Fig. 1. Reactivity with mean life time

small amount of high level nuclear waste. For controlling

and transmutation of radionuclides physical operation can

be made at reactor for mitigating waste virility. In figure

1, reactivity is decreased with mean life time and stable

period is shown. In this paper, nuclear waste treatment

by radioactive and Electro-Magnetic (EM) shielding via

dose conversion factors [7], photons and neutrons response

functions has been explained. Moreover, Quality-Factor [8],

dose rates [9] and kerma [10] is calculated, controlled and

explained for that purpose. Finally Poisoning [11] of Xenon

and Samarium and Decay Chain has discussed. In addition

with the waste treatment, data transmission of power gen-

eration from nuclear plant to NLDC is a matter of concern.

For that reason, data transmission security has grave im-

portance as foreign intelligence have an askance look on

power generation and transmission data of nuclear power

plant. In this paper, secured data transmission of nuclear

power plant to National Load Dispatch Center (NLDC)

is proposed using digital watermarking [12] scheme and

proper treatment [13] and controlling of nuclear waste is

proposed as a cardinal feature.

II . ELECTROMAGNETIC (EM) RADIATION SHIELDING

TECHNOLOGY

In analysis, the source and shielding are identified and

the task is to influence the resultant dose. The task is to

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Fig. 2. Cross sections and dose conversion factors

regulate the existence of the shielding required to accom-plish the destination. At commencement it must be said that

screening contrives and shielding analysis are complemen-

tary activities. In convening, the source is identified and a

target dose goal is specified. Whether one is engaged in

a hand computation or in a most elaborate MonteCarlomodel, one is confronted with the chores of (1) qualifying

the source, (2) characterizing the nature and rarefying

dimensions of the shielding materials, (3) valuating at a

target location the radioactivity strength and possibly its

angular and energy dispersions, and (4) commuting the

saturation to a dose or reaction substantive in terms of

actinotherapy cores. MonteCarlo codes are amenable tothese more complex shielding problems and have become

more and more popular as high-speed ciphering has become

uncommitted to so many people. Generally, nevertheless,

they do require considerably more expertise and aiming to

use and are often much denser in accomplishing a root than

are the deterministic methods.

A. Cross sections and dose conversion factors

Two more foundation stones need to be in place to

support a mature radiation shielding technology.

Working with buildup factors computed using the

PALLAS code, Harima developed a data fit in the

following form, called the geometric progression formula.

Fig. 2 presents cross sections and dose conversion factors.

K (µ, r) = c(µr) + dtanh(µr/ξ − 2) + 0.96

1.96(1)

Where a, b, c, d, and ξ are parameters that devolve on

the gamma-ray energy, the attenuating medium, and the

nature of the response. This appears to be a very exotic,

even eccentric, fitting formula. That may be so, but it

is so an inordinately accurate pattern, as is illustrated in

Fig. 1 above. Both the results of PALLAS calculations

and the constants for the patterned advance buildup factors

are tabularized in pattern criteria. One is a comprehensive

set of samples, or interaction coefficients, explicating not

only reactions but also dosimeters colligated coefficients

Fig. 3. Buildup factors computed by geometric progression method thePALLAS code

such as those for energy dethronement. Another is a set

of effluence-to-dose factors relevant to a comprehensive

alignment of dosimetry stipulates. By controlling these

parameters, PALLAS code and hyperbolic functions, dose

conversion factors can be controlled. Fig. 3 shows buildup

factors computed by geometric progression method the

PALLAS code.

B. Phantom-Related Dose

The phantom dose, in fact, is a point function and serves

as a standardized reference dose for instrument calibra-

tion and radiation protection purposes. A local irradiation

dose within a simple geometrical phantom or some sort

of intermediate dose within an anthropomorphic phantom

by phantom-related dose is considered. Dose conversion

factors are also usable for three profundities of incursion

into the geometric phantom: (1) a 10-mm depth, the dosage

being called the ambient dose, a foster to the earlier whole

body dose and the dose suitable for instrument standardiza-

tion; (2) a 3-mm depth, suited for exemplifying the dose to

the lens of the eye; and (3) a 0.07-mm depth, desirable for

constituting the dot to the skin. Fig. 4 is presenting photon

response functions and fig. 5 shows neutron response

functions. Fig 6 and 7 compare response functions for

photons and neutrons, respectively. At energies over about

0.1 MeV, the assorted photon response mappings are veryclosely equal. Personnel dosimeters are usually calibrated

to contribute responses proportional to the ambient dose.

This is a fortunate position for radiation mensuration and

surveillance determinations. Both the ambient dose and

the tissue Kerma closely estimate the efficacious dose

equivalent.

III. CONTROLLING OF RADIATION DOSIMETRY

PARAMETERS

A. Controlling Doserates

The unshielded dose rate at the dose point is given by

D =kSEµen

4Πρr2(2)

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Fig. 4. Photon Response Functions

Fig. 5. Neutron Response Functions

For Shielded primary photon dose rate, primary photon

dose rate is attenuated exponentially, and the dose rate from

primary photons, taking account of the shield, is given by

D =kSEµene−µt

4Πρr2(3)

where for the photons in the shield material, µ is the

linear attenuation coefficient. This expression does not

account for the buildup of secondary radiation and will

generally underestimate the true dose rate, especially for

thick shields and when the dose point is close to the shield

surface. For shielded dose rate accounting for buildup

the added effect of the buildup is taken into account by

incorporating a point isotropic source dose buildup factor,

B

D =kSEµenBe−µt

4Πρr2(4)

The order of magnitude of the buildup factor hinges upon

the origin and screen geometry, the outdistance from the

shield control surface to the dose degree, photon energy,

the shield corporeal and heaviness. Now,

D =kSEµenBe−µt

4Πρr2[A1e

α1µT + (1 −A1)eα1µT ] (5)

An intimately concerned deterministic quantity, used

only in association with circuitously ionizing (uncharged)

radioactivity, is the Kerma, an acronym for ’Kinetic Energy

of Radiation Absorbed Per Unit Mass’. The absorbed doseis, in principle, a mensurable quantity; but in many contexts

it is unmanageable to compute the immersed dose from

radiation effluence and material properties. The calculation

of the kerma (rate) is closely related to the reaction (rate)

density. If, at some point of interest in a medium, the

fluence of radiation with energy E is φ, the kerma, k at

that point is

K (E ) =µtr(E )

ρEφ (6)

With the assumption of charged particle equilibrium, the

absorbed dose rate, D0

D0 = 1.6× 10−10exp[−µr]µenES p

4Πρr2(7)

Now,if only elastic scattering is of importance, the neu-

tron kerma is,

K = 1.6× 10−10Eφfsµs

ρ(8)

In a neutron dissipate, the scattering nucleus recoils

through the medium producing ionization and innervations

of the ambient atoms. The primary mechanism for trans-

ferring the neutrons kinetic energy to the medium is from

neutron scattering interactions, when fast neutrons pass

through a medium. The average neutron energy loss (andhence average energy of the recoil nucleus) for isotropic

elastic scattering in the center-of-mass system of a neutron

with initial energy E .

B. Controlling Quality-Factor and Dose Equivalent

The Quality-Factor and the Absorbed Dose are both

point functions that is deterministic measures that may be

assessed at points in infinite. Their product is identified as

the dose equivalent H and is distinguished as a reserve

assess of radiotherapy jeopardy when enforced in the

context of establishing radiation protection guideposts and

dose determines for population radicals.

The dose equivalent

H = Qf ×D = Qf ρ−1× 1.6× 10−10Eφµen (9)

where Dis the absorbed dose at the point of interest.

In fig. 6 controlling quality factor and dose equivalent is

shown.

IV. NUCLEAR WASTE TREATMENT BY

POISONING: DECAY CHAIN

In a reactor core the fission products that accumulate are

of concern for two explanations. First, they play long-term

ignite origins through their disintegrations. Second, they act

as epenthetic neutron absorbent or toxicants that, over time,

decrease the thermal utilization factor and, thus, bring in

electronegative reactivity into a core. For fission products

acquired from the fission of 235U , it is often presumed that

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Fig. 6. Controlling Quality Factor and Dose Equivalent

Fig. 7. Poison Reactivity

each fission produces 1 atom of static poisonous substance

with an concentration cross section of 50 barns. While this

simplistic rule-of-thumb exploits for long-term reckonings

of burn up effectuates, the two particular poisons 135Xeand 149Sm have such prominent absorption cross sections

that they must be tempered on an individual basis.

A. Poison Reactivity

Fig. 7 shows poison reactivity. To determine the reactiv-

ity transient caused by a particular fission product poison,

N pt/

f , buildup equations for the poison decay chain

and a quantity that is found from the decay.

The reactivity ρ p introduced by a fission product poison

is directly proportional to its average concentration N p in

the core.

ρ p =keff − 1

keff =

keff − 1

keff (10)

wherek

eff indicates the core with the poison included

and keff refers to the same core without the poison. Since

the poison changes only the thermal utilization factor,

the two multiplication factors are related to each other

Fig. 8. Equilibrium Xe(135)and I(135) concentrations as a function of the steady-state flux density

Fig. 9. Xe(135) transients shutdowns from equilibrium at constant fluxdensities

by keff =keff f /f . If we assume the unpoisoned core iscritical keff = 1,then poison reactivity is given by,

ρ p −0.6σ paN p

f = −σ pa

N pf

η

ν f (11)

B. Xenon Decay Chain and Poisoning

A very small nuclear denseness of Xenon nuclide can

have a right smart reactivity consequence. Of all isotopes it

has the largest thermal neutron absorption cross section. For

Counterbalancing Xenon Poisoning, a reactor operating at a

constant flux density φ0, the equilibrium concentrations of 135I and 135Xe are found from decay per buildup equations

by setting the time derivative to zero. The result is

I 0 = γ I (

f

λI )φ0 (12)

X 0 = [φ0γ I + φ0γ X ]

f

λX + σXa φ0(13)

Equilibrium Xe(135)and I (135) concentrations as a func-

tion of the steady-state flux density is shown in Fig. 8.

From equations it is understood that, while the 135Xeconcentration is independent of φ0 at high flux density

levels, the 135I concentration continues to increase linearly

withφ0.

Xe(135)transients shutdowns from equilibrium

at constant flux densities is shown in Fig. 9.135I would decay away, and the 135Xe concentration

would finally begin to decrease as it decays. 135Xetransient

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Fig. 10. Xe(135) transient for the buildup to equilibrium

Fig. 11. Xe(135)Equilibrium flux density before shutdown

for the buildup to equilibrium is shown in Fig. 10 following

the shutdown from various flux levels.

If during the shutdown transient, reducing the 135Xereactivity temporarily to below its equilibrium values, the

reactor were started up again, the large absorption cross

section for 135Xe would cause this nuclide to be burned

up very rapidly. Examples of these restart transients are

shown in Fig. 9-10. In many power or propulsion reactors,

the time to poison is usually only a few tens of minutes, and

the operator may go through substantial force to acquire

the reactor resumed before it poisons out so as to avoid

a protracted period of lost production. Once the reactor

has poisoned out, it is requisite to postponement until

the negative135

Xe reactivity has peaked and descendedback to a level that can be offset by all controllable

positive reactivities. The time from the closure until the

reactor poisons out is the called the time-to-poison. The

interval throughout which the reactor cannot be resumed is

called the poison shutdown time and is typically of 15-

25 hours continuance. It is unimaginable to restart the

reactor, and the reactor is stated to have poisoned out.135Xe equilibrium flux density before shutdown is shown

in Fig. 11.

C. Samarium Poisoning

The second fission product poison which must be ac-

counted for explicitly in power reactors is 149Sm. This

stable nuclide is a daughter of the fission products 135Smand 135Pm. The generation rate of 149Sm is the decay rate

Fig. 12. The buildup of Sm(149)to equilibrium

Fig. 13. Sm(135)transient for the buildup to equilibrium during a start

of 149

Pm. There is negligible production of 149

Sm as adirect fission product. Since 149Sm is stable, the only way

it can vanish is for it to absorb a neutron which it does at

a volumetric rate of σsaφ(t)S (t), where S (t) is the average149Sm concentration. Thus the decay/buildup equations for149Pm and 149Sm are

∆P (t)

∆t= −λP P (t) + λP

fφ(t) (14)

∆S (t)

∆t= λP P (t)− σSaφ(t)S (t) (15)

Because of the long half-lives of 149Pm and 149Sm, the

buildup of 149

Sm to its equilibrium level takes many tensof hours, especially for reactors operating at low average

flux densities φ0. It is seen the equilibrium 135Sm is,

S 0 =(γ P

f )

σsa) (16)

Fig. 12 shows the buildup of 149Sm to equilibrium a

level that is independent of the flux density.

Thus at equilibrium, all reactors have the same amount

of 149Sm poisoning.Fig. 13 shows 149Sm transient for the

buildup to equilibrium during a start.

V. DATA TRANSMISSION TO NLDC: SECU RITY

CONCERN

This far, in this paper, we discussed only about an

efficacious way of treating nuclear waste materials. But

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Fig. 14. Watermarked DCT coefficient

we also have to keep in mind that this waste handling

actually takes place in a nuclear power plant. So various

data of great importance about this waste treatment process

needs to be conserved and transmitted frequently. National

load displacement center (NLDC) of any country, which

keeps the national load distribution and management go-

ing, needing an enormous amount of data to receive and

transmit, is a good example. For a secured exchange of this

data we are proposing the concept of digital watermarking.

Digital watermarking is an art of digital data hiding inanother data. In this paper we used an audio signal to host

our waste data of concern. Among various techniques of

audio watermarking, we used “DCT Coefficients Replace-

ment Method”. In this method a host audio signal is first

framed, considering samples within 25.5 milliseconds as

one frame. DCT (Discrete Cosine Transform) coefficients

of each frame are then calculated, with overlapping frames

to reduce edge effect. Then information data, nuclear waste

data in this case, are represented by corresponding ASCII

values and these values are encrypted by an encryption

code. By a scaling factor, known to both receiving and

sending end, these ASCII vales are scaled down to ad-

just with low amplitude DCT coefficients having very

small impact on perception of audio signal. Then DCT

coefficients beyond a certain threshold are replaced by

information signal. The information code being inserted

last thing we have to do is to calculate IDCT (Inverse

Discrete Cosine Transform) values to obtain audio signal

back, with watermark perceptually impossible to detect,

prior to transmission through an unreliable channel. After

audio signal is received on the other end of channel, similar

procedure is used to extract the information signal. As both

scaling factors and encryption key are known in this end

too, there is no difficulty to recover the data. So, obvious

from above discussion, watermarking is providing extra ad-vantages over conventional encryption. Firstly the existence

of hidden data has to be sensed, decryption of data comes

after that. Again randomization of watermarking opens a

wide range of encryption options. In fig. 14. watermarked

DCT coefficients are shown.

VI. CONCLUSIONS

Radioactive waste comes from many places in the nu-

clear fuel cycle, but fission products generated in reac-

tors dominate both the high-level and low-level problems.

Nuclear waste management technologies via PUREX pro-

cess, ISR and Laser Isotope Separation(LIS)technology,

RSICC software, DIMS system development and modern-

ized radioactive waste treatment processes are adopted at

earlier and it is apprehend that, nuclear waste treatment

technology is more efficacious than the conventional one.

In this paper, nuclear waste treatment by radioactive and

electromagnetic shielding via dose conversion factors, pho-

tons and neutrons response functions has been explained.

Moreover, analyzing of Quality-Factor and Poisoning de-

cay of Xenon and Samarium has discussed. In addition,

modernized radioactive waste treatment processes as well

as secured data transmission of nuclear power plant toNational Load Dispatch Center (NLDC)is proposed using

Digital Watermarking technique. This data transmission

security has grave importance as foreign intelligent services

have an avarice look on power generation data of nuclear

power plant . Through proper management and treatment

technologies of nuclear wastes discussed in this paper,

world can have nuclear energy as a safe and clean future

energy reservoir.

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