ML20207F231

Rev 3 to SAR for Chem-Nuclear Systems Model CNS 8-120B Type B Radwaste Shipping Cask

ML20207F231
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Site:	07109168
Issue date:	05/31/1999
From:	CHEM-NUCLEAR SYSTEMS, INC.
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SAFETY ANALYSIS REPORT FOR CHEM-NUCLEAR SYSTEMS MODEL CNS 8-120B TYPE B RADWASTE SHIPPING CASK REVISION 3 MAY 1999 CHEM-NUCLEAR SYSTEMS CORPORATE HEADQUARTERS 140 STONERIDGE DRIVE COLUMBIA, SOUTH CAROLINA 29210 l

l 1

9906000120 990525 'T PDR ADOCK 07109168 i

i C

PM i

1

m..

Revision 3 May 1999 l

4.5 Periodic Verification Leak Rate Determination Usino R-12

, Test. Gas j

This section contains calculations to determine the periodic verification test measurement that is equivalent to the maximum permissible leak rate as determined using ANSI N14.5-1997(Refer-l ence 4).

4.5.1 Introduction l

The purpose of this calculation'is to determine the allowable leak rate using the R-12 halogen gas'and R-134a that may be used l

to perform the annual verification leak tests on the CNS 8-120B cask.

The text of this document is prepared using Mathcad, Version 6.0, software.

Most conventions used11n the text are the same as'nor-mal practice.

A benefit of the Mathcad code is that it automati-cally carries all units with the variables used in the calcula-tions.

The code.also allows output of variables in any form of l

'the' fundamental units (length, mass, time, etc.), allowing for automatic conversions between unit systems without the need for

. conversion factors. All Mathcad calculations in this Section 4.5 have been verified by hand calculations.

This calculation uses formulas presented in ANSI N14.5 - 1997 (Ref. 4)'.

4.5.2 Detector Sensitivity Calculation - Test Conditions This section determines the sensitivity necessary for a leak test performed with R-12 halogen gas.

This test is performed using a General Electric Model H-25 leak detector, along with a Yokogawa Model LS-20 leak standard containing R-12 halogen gas.

The leak standard is used to calibrate the leak detector to alarm at the

. maximum allowable test leak rate.

The test is performed by fill-ing the region between the'o-rings with 25 psig of R-12 halogen gas.

.First, using the Standard Allowable Leak Rate from Section 4.3.2 of the SAR, determine the maximum possible diameter hole in the cask o-ring that would permit this leak rate at standard condi-tions.

2 2.0910 ' std Section 4.3.2 of 8-120B SAR Lstd sec Where, for air at standard conditions:

T = 298-K l-P a l.0 atm Upstream test pressure u

4-15 i

1

.4 Revision 3 May 1999

~ 4.5 Periodic Verification Leak Rate Determination Usino R-12

,. Test. Gas This section contains calculations to determine the periodic verification test measurement that is equivalent to the maximum permissible leak rate as determined using ANSI N14.5-1997 (Refer-l

. ence 4).

- 4.5.1 Introduction The purpose of this calculation is to determine the allowable leak rate using the R-12 halogen gas and R-134a that.may be used l

to perform the annual verification leak tests on the CNS 8-120B cask.

The text of this document is prepared using Mathcad, Version 6.0, software.

Most conventions used in the text are the same as nor-mal practice.

A benefit of the Mathcad code is that it automati-cally carries all units with'the variables used in the calcula-tions.

The code also allows output of variables in any form of the fundamental units (length, mass, time, etc.), allowing for automatic conversions between unit systems without the need for conversion factors. All Mathcad calculations in this section 4.5 have been verified by hand calculations.

This Mlculation uses formulas presented in ANSI N14.5 - 1997 (Ref. (s.

4.5.2 Detector Sensitivity Calculation -' Test Conditions This section determines the sensitivity necessary for a leak test performed with R-12 halogen gas.

This test is performed using a General Electric Model H-25 leak detector, along with a Yokogawa r.

Model LS-20 leak standard containing R-12 halogen gas.

The leak l

standard is used to calibrate the leak detector to alarm at the maximum allowable test leak rate.

The test is performed by fill-

'ing the region between the o-rings with 25 psig of R-12 halogen gas.

First, using the Standard Allowable' Leak Rate from Section 4.3.2 of the SAR, determine the maximum possible diameter hole in the cask o-ring that would permit this leak rate at standard condi-tions.

lstd : 2.0910 ' std **

Section 4.3.2 of 8-120B SAR SCC Where, for air at standard conditions:

T m298 K P u lh atm Upstream test pressure l

u l

F 4 -15

]

i

i l

Revision 3 May 1999 Pd :.01 atm j

, Downstream test pressure P, s 505 atm. Average' test pressure 1

Mair 29

• I' Molecular weight of air p air = 0.0185cP Viscosity of air I'

The diameter of the o-rings on the CNS 8-120B are 0.275 in.

As-sume a, which is the length of the hole in the o-ring is 25% of i-the o-ring' diameter; then:

Oring :.275 in Diameter of the o-ring a ;25 % o ing r

i a = 0.175 cm i

From ANSI N14.5 - 1997:

l F (D) 2.4910' D* cP std-Eqn. B3 - ANSI N14.5-e a palisec.atm -

l l

3.81 10'.D' cm gm" '

F (D)-

Eqn. B4 - ANSI N14.5 m

e l

a P K - mole sec a

P tsid(D) ': (F (D) - F y D))-(P -- P )' * -

Eqn. B5 - ANSI N14.5 e

u d

p u

l Solve this equation iteratively for D.

Therefore, the maximum possible diameter of hole'in the 0-ring is that would permit a leakage rate of L,,,

is:

max 235510" c

(_

D

=

.Next, determine the equivalent air /R12 mixture (Lmix) that would

)

~

-leak from Dmax during a leak test.. Assume the O-ring void is pressurized to 25 psig (2.7 atm) with an air /R12 mixture.

1 Pmix.: 2.7 atm i

I i

i 4-16 s.

\\

Revision 3 May 1999

. Pair = 14atm -

'PR12 = 1.7 atm -

- 1

'Pm'*- P '

8' P * -,

P = 1.85 atm a

-2

=>

MR12'=121 8" ANSI N14.5---1997-mole H R12 = 0.0124 cP ANSI N14.5 1997

'MR12-PRI2 M airPair Mmix -

Eqn. B10 - ANSI N14,5 Pmix Mmix= 86.9) 8" -

o mole 1

Eai/ Pair" P R12 R1 P

p Eqn. Bil - ANSI N14.5 mix p mix = 0.015 cP Determine Lmix as a function of temperature.

Assume the viscosi-ties of air and R12 do not change significantly over the range of temperatures evaluated:

T = 273 K.278 K. 318 K Temperature range for test: 320F to approx.

i 1130F l

Substitute these properties for the air /R12 mixture and the maxi-mum diameter hole ( D,,,)

into equations Eqn. B2, B3, and B5 l

from' ANSI N14.5:

1 2 4910' D""*# cP std 3

F :-

F = 2.99210' *

• I e

e a.pm'ixsec atm sec.atm 3

3.8110' D cm gm" max '

l F (T) =

m g

l aP,K mole sec

).

r.

4 - 17

Revision 3 May 1999 P

LmfT) lF,.. F fT)) 'Pmix-Pairj n

mi T (T) - (T F - 273K) -32!

y

5. K

-6 3.83 10 6

3.825 10 r

i

-6 3.82 10

[

/

6 I mi/TD.81510

/

0 3.81 10 6

3.805 10 1

6 3810 j

20 40 60 80 100 120 Tr(T)

Fia.4.1 - Allowable R-12/ Air Mixture Test Leakace, cm3/sec, ver-sus test temperature, dea.F The R-12 component of this leak rate can be determined by multi-i plying the leak rate of the mixture by the ratio of the R-12 par-tial pressure to the total pressure of the mix, as follows.

P R12 LRifT) -LmfT)- -

pmix 4 -18

1 l

Revision 3 May 1999 6

2.415 10 2.41 10

__ ___.i.______

-6

{

1 1

-6 2.405 10 I

l l_'_ Rift)

-6 2.4'10

_ _._ l _ _ _

_ _ _j__.____._ _____

1 6

2.395 10

__g____.__._._..___

i i

i

-6 2.39 10 20 41 60 80 100 120 THT) j Fic.4.2 - Allowable R-12 test leakace, cm3/sec versus test tem-perature. dea.F Determine the equivalent mass flow rate for LR12 in oz/yr:

PRlrV

^

N(T)

Ideal Gas Law RT o

where, b #"1 'E Ro mole k This data can then be used to convert the volumetric leak rate for R-12 calculated above to a mass leak rate.

By dividing N by V,

the number of moles per unit volume can be multiplied by the molecular weight of the gas and the maximum allowable volumetric leak rate to determine the maximum allowable mass leak rate, as a function of test temperature as shown in the graph below.

The conversion from grams per second to ounces per year is also shown below.

14T) LRifT)

E M R12 V

oz gm 6 oz

=l.11310 Conversion of gm/sec to oz/yr sec yr 4 - 19 l

l l

. Revision 3 May 1999 0.025 f

l j

j.

j

. 0.024 1.

3 j

L( T Jo.023 t-1.

1 0.022 L

---f y

{

i i

I t

I i

20.

- 40 60 80 100 120 T p(T)

Fic.4.3'

' Allowable R-12 test leakace, oz/vr, versus test tem-Derature, dea.F The graph.above can be.used to determine the allowable leak rate based on the temperature at the time of the test.

According to ANSI N14.5. methodology, the maximum allowable leak rate must be divided by 2 to determine the minimum' sensitivity for the test. A graph of the required sensitivity in oz/yr is presented below:

0.0125 i

l t

4----

0.012 I

10:15 d

-7 t

i 0.011

+

1 1

1 i

j 0.0105 20 40 60 80 100 120 T y(T)

Fia.4.4 - Allowable R-12 test leakace sensitivity, oz/vr. versus test temoerature, dea.F The values presented in Figure 4.4 should be used to determine the sensitivity to' calibrate the leak detector prior to the test.

' 4. 6 Periodic Verification-Leak Rate Determination Usino R-134a Test Gas This section contains calculations to, determine the. periodic verification test measurement that is equivalent to the maximum 4 20 c

Revision 3 May 1999 permissible leak rate as determined using ANSI N14.5-1997(Refer-l ence,4).,

4.6.1 Introduction The purpose of this calculation is to determine the allowable leak rate using the R-134a halogen gas that will be used as an alternative to perform the annual verification leak tests on the CNS 8-120B cask.

This halogen gas is now in widespread use as a replacement gas for R-12 in-many industrial applications.

Prop-erties for R134a are attached in Appendix 4.1.

The text of this document is prepared using Mathcad, Version 6.0, software.

Most conventions used in the text are the same as nor-mal practice.

A benefit of the Mathcad code is that is automati-cally carries all units with the variables used in the calcula-tions.

The code also allows output of variables in any form of i

the fundamental units (length, mass, time, etc.), allowing for automatic conversions between unit systems without the need for conversion factors. All Mathcad calculations in this Section 4.6 have been verified by hand calculations.

This calculation uses formulas presented in ANSI N14.5 - 1997.

l 4.6.2 Detector Sensitivity Calculation - Test Conditions i

The test is performed by filling the region between the o-rings with 25 psig of R-134a halogen gas. In Section 4.5.2, it was de-termined that the maximum possible diameter hole in the cask o-ring (D, that would permit the standard leak rate (L a =

2. 09x10~g)std cm'/sec) is :

u D

= 2.35510 c max Next, determine the equivalent air /R134a mixture (1 mix) that would leak from Dmax during a leak test.

Assume the O-ring void is pressurized to 25 psig (2.7 atm) with an air /R134a mixture.

I' mix 2.7 atm l' air = 1.0 utm PR134a lJatm P

P, = 1.85 atm a.

=>

I 4 - 21 l

\\

Revision 3 L

May 1999 l-l The properties of R134a'are:

l E*

M R134a 103

~ Appendix 4.1 mole o

PR134a = 0.012.cP Appendix 4.1 M R134sPRl34a* M P

ai/ air Mmix

• p,

Eqn. B10 - ANSI N14.5 mtx E"

Mmix= 74.9&mole -

MaigPair+ PR134sPR134a E mix =

p,

Eqn. Bil - ANSI N14.5 mix pmix = 0.014 cP Next, determine Lmix as a' function of temperature.

Assume the viscosities of air and-R134a do not change significantly over the range of temperatures. evaluated:

T = 273 K,278-K.,318 K Temperature range for test: 320F to approx.

1130F Substitute these properties for the air /R134a mixture and the maximum diameter hole (D,)

into equations Eqn. B2, B3, and B4 o

from ANSI N14.5:

F - 2.4910' D "4 cP std 3

-6 cm e

p 3,o4430

' a p mixsec atm C

3 sec atm r- -

3.8F10' D cmgm" max' ;

' F (T) =

m aP,K mole sec P

mi(T) =(e s e 3

a F + F fT))-[ mix-Pair"p L

c n

mix 4 - 22

[".

.\\

e:.

p Revision 3 May 1999

. r q

Ty(T) :!(T F-273K) 9 -+32l

$K j

t

-6' 3.92 10 i

t-3.91910 l

3.91+10' 0-~ -- 7 I

i i

i

. 3.90F10 Lmi/T) j

--6 3.9 10 p_

4 l

I 3.89F10 t-i i

i.

l t

- 3.g9'l0

_ _ _4_

l

-6 j

i

-6 I

3.88910 20 40 60 80 100 120 Tr(T)

Fia.4.5 - Allowable R-134a/ Air Mixture Test Leakace, em3/sec.

versus test-temoerature, dec.F I

.The.R-134a' component of this leak rate can be-determined by mul-tiplying the-leak rate of.the mixture by the ratio of the R-134a partial pressure to the total pressure of the mix, as follows.

PR134a LR134dT) = LmfT) p,

mix l

l^

l l

1 4 - 23

'~

Revision 3 May 1999 l

2.47 10

{

i

-l i

-6 j 2.46510 4

1

}

k 2*.id 1

- --q- -q I

l LR134dT) l j ___rl l

2.455 10"6

[

i i

e 4

E 2.45 10 t

5 20 -

40 80 100 120 Tg4T)

Fic.4.6 - Allowable R-134a test leakace, cm3/sec versus test tem-Derature, dea.F Determine the equivalent mass flow rate for LR134a in oz/yr, the measurement used'by the leak detector:

PRl34dV N(T) :

Ideal Gas Law RT o

where, Ro =

mole k,' "

Th'is da't'a.can then be used to convert the volumetric leak rate for R-134a calculated above to a mass leak rate.

By dividing N by V, the' number of moles per unit volume can be multiplied by the molecular' weight of the gas and the maximum allowable volu-metric leak rate to determine the maximum allowable mass leak rate, as a function of test temperature as shown in the graph be-low.

The conversion from' grams per second to ounces per year is also shown below.

14T) :LR134gT) bN ; i lI

,g34g V

oz gm 6 oz

=1.11310 -

Conversion of gm/sec to oz/yr sec.

yr 4 - 24

o, P

~

R'evision 3 L

May 1999

\\

l 0.022

.t

-I t

0.021 1

i I

i

~

~

-uT) 0.02 1

l i

i i

l l

1-0.019 l

i 0,018 20 40 60 80 100 120 TpT)

Fio.4.7 - Allowable test leakace, oz/vr. versus test t'emperature,

dea.F The graph above can be used to determine the allowable leak rate based.on the temperature at the time of the test.

According to ANSI N14.5 methodology, the maximum allowable leak' rate must be i

divided by 2 to determine the minimum sensitivity for the test. A graph of the' required sensitivity in oz/yr is presented below:

O 0li l

t j.

i I

I i

i 1

i ccios

-t q-j p

i i

i li,%0i l

t I

i i

oms

-. - + - -

i 0.009 20 40 60 80 100 120 l

T,4 T )

Fic.4.8 - Allowable test leakace sensitivity, oz/vr. versus test temoerature, dec.F The values presented in Figure 4.8 should be used to determine 7,

t the serisitivity to calibrate the leak detector prior to the l

test.

i l

l 4 - 25 1

f' Revision 3 May 1999 4.7 References 1.

' Weast, Robert C. and Astle, Melvin J.,

Handbook of Chemistry i

and Physics, 63" Edition,-CRC Press, 1982.

2.

Van Wylan, Gordon J.

and Sonntag, Richard E.,

Fundamentals of Classical Thermodynamics.

Second Edition, John Wiley and j

Sons, Inc., 1973.

3.

Thomas, Lindon C.,

Heat Transfer - Professional Version, I

Prentice-Hall, Inc., 1993.

4.

American National Standard for Leakaoe Tests on Packaoes for

{

Shioment of Radioactive Materials, American National Stan-I dards Institute, Inc., New York, ANSI N14.5-1997, 1997.

1 l

l 4 26 L