Text

Summary of 970211-12 Meeting W/Westinghouse in Los Altos,Ca Re Issues Related to AP600 Source Term.List of Attendees Encl
	ML20136H692
Person / Time
Site:	05200003
Issue date:	03/14/1997
From:	Joseph Sebrosky; NRC (Affiliation Not Assigned)
To:	; NRC (Affiliation Not Assigned)
References
	NUDOCS 9703190275
	Download: ML20136H692 (106)
	v • d • e

.. -

(

b(\\bfcd b{

je urg.

k UNITED STATES bW g

j NUCLEAR REGULATORY COMMISSION l

WASHINGTON. O.C. 30eeH001

.o k...../$

4 March 14, 1997 APPLICANT: Westinghouse Electric Corporation FACILITY:

AP600 l

SUBJECT:

SUmiARY'0F FEBRUARY 11 AND 12, 1997, MEETING WITH WESTINGHOUSE TO DISCUSS ISSUES RELATED TO THE AP600 SOURCE TERM The Nuclear Regulatory Commission (NRC) staff and representatives of Westing-house ^ Electric Corporation held a public meeting on February 11 and 12, 1997 at Westinghouse's contractor's office in Los Altos, California to discuss issues associated with the AP600 source term. Attachment 1 is a list of meeting attendees. Attachment 2 through 4 are the handouts provided by the i

staff during the meeting. Attachment 5 and 6 are the handouts provided by Westinghouse's contractor Polestar during the meeting.

Prior to the meeting there were three letters that addressed some of the issues that'the meeting was intended to resolve:

(1)

Westinghouse Letter from B.A. McIntyre to T.R. Quay dated December 3, l

1996, " Request for Information on NRC Model for Thermophoretic Removal of Containment Aerosol Removal Coefficients (NTD-NRC-96-4894)'

(2).

NRC Letter from T.J. Kenyon to N.J. Liparulo dated January 10, 1997,

" Discussion Items on Source Term Related Issues for the AP600"i (3)

Westinghouse Letter from B.A. McIntyre to T.R. Quay dated February 7, 1997, " Position Paper in Support of the Assumption of Complete Mixing of Aerosols in the AP600 Containment Atmosphere following a Loss of Coolant Accident",(NSD-NRC-97-4978)

All three of the above. letters were discussed during the meeting.

In addition to the concerns that were addressed in the above letters there were several additional concerns that arose during the course.of the meeting. The issues that were resolved during the meeting are listed in Attachment 7.

The unresolved issues that require NRC and/or Westinghouse actions are listed in.

The staff requests that Westinghouse incorporate the responses to Westinghouse action items identified in Attachment 8 into forthcoming Westinghouse responses to RAI 470.38 through 470.40.

While the information in attachment 7 and 8 provide the details of the l

specific items that were discussed, there was a recognition at the end of the meeting that there were four factors that seem to explain the majority of the difference between the staff's and Westinghouse's calculated value for the

/

l fission product aerosol removal rate for the AP600,- These four factors and their-relative impact on the differences are:

5 3

i o.n o o f'yrp 9703190275 970314 iNf h[

DR ADOCK 052000 3

i 4

(

l

' March 14, 1997

)

(1)

The staff and Westinghouse used different thermal hydraulic codes in their calculations.

It was generally agreed however that this would explain only a minor portion of the difference.

(2)

The staff used a value of 1848 square meters for the upward-facing horizontal sedimentation area in it's analysis based on Westinghouse response to RAI 470.23 (Westinghouse letter dated April 7, 1995, NDT-NRC-954430) while Westinghouse used a new value of 3500 square meters.

This would have a major effect on the amount of aerosols that are calculated to be removed by sedimentation. However, sedimentation is only one of three mechanisms for removal of the aerosol particle (the others are diffisiophoresis and thermophoresis) so the overall effect i

would be reduced.

[

(3)

The value that the staff used in its analysis for the shape factor in the thermophoretic model was different than Westinghouse's value.

In essence Westinghouse assumed that the shape of the aerosol particle did not effect thermophoresis, while the staff's result assumes that it did.

(It was recognized that the effect of the shape factor for diffisiophoresis was minor, but that the shape factor could also influence the sedimentation aerosol removal rate).

It was agreed that this was a major reason that the staff's and Westinghouse's overall values for the fission product aerosol removal rate are different.

i (4)

Westinghouse still felt that the issue that was raised in its Decem-ber 3, 1997 letter (i.e. how the temperature wall gradient was calculated in staff's analysis) may still partly contribute to the difference. The staff did not share this view, and this issue was discussed during the staff's presentation (see attachment 3).

Westing-house will evaluate the staff's presentation to see if it has any l

additional concerns.

There was also a discussion about which uncertainty percentile curves in

' for the aerosol fission product removal rate the staff intends to use in its calculations. The curves developed by the staff's contractor were based on a Monte Carlo uncertainty analysis which led to a 10 percent (i.e.

10 percent of the Monte Carlo values fell below this curve ) and a 90 percent I

bounding curves that can be found in Figure 2 of Attachment 3.

The staff told Westinghouse that it is the staff's intention to use the 10 percent i

uncertainty percentile curve as the basis for aerosol removal calculations.

.~.-

_. ~....

~.

~

I.

2-s 3-March 14, 1997 At the end 'of the meeting ~ there was' a discussion on the path for resolving the different values calculated for the-aerosol fission product removal rate.

Westinghouse understood the staff?s approach and will determine a course of action based on the. results of. this meeting.; 'It was recognized that Westing-house must justify to the staff that the value it 'uses for design basis

accident calculations'is conservative.

s 3

original signed by:

Joseph M. Sebrosky, Project Manager

. Standardization Project Directorate-Division of Reactor Program Management Office of1 Nuclear Reactor Regulation r

-Docket No.

52bO3

. Attachments: As stated cc w/ attachments:

See next page DISTRIBUT::0N w/ attachments:

' : Docket F1 e-PDST R/F TKenyon PUBLIC BHuffman DTJackson-JSsbrosky DISTRIBUTION w/o attachment:

SCollins/FMiraglia, 0-12 G18 AThadani, 0-12 G18 RZimmerman, 0-12 G18 TMartin.

DMatthews TQuay-Dross, T-4 D18 WDean, 0-17.G21 ACRS (11)

'JMoore, 0-15 B18 REmch, 0-10 D4 JLee, 0-10 D4~

JKudrick 0-8 H7 MSnodderly, 0-8 H7 s

DOCUMENT NAME: A: SOURCE. SUM t

"h e Copy with.tt.chment/encloswo "N* = No copy n m.

,y.e w. mw we m in. m.u c = co,,

iihoui.n.chmeshe awe 0FFICE PM:PDST:DRPM JC:PERB:QRPM_

SCS$:b(Sh\\ \\

D:PDST:DRPM l l

NAME JMSecrosky:sdR5 REmch.-WW, JKudricW\\\\ \\

TRQuay P

DATE 1/ </97:

(/-

03/ P/97 T 03/9/97 \\\\ $

}/iy/97 i

0FFICIALREf0RD(Oy j

g l

Y 4

'A, i

e

L

^

Westinghouse Electric Corporation Docket No.52-003 cc: Mr. Nicholas J. Liparulo, Manager Mr. Frank A. Ross j

Nuclear Safety and Regulatory Analysis U.S. Department of Energy, NE-42 l

Nuclear and Advanced Technology Division Office of LWR Safety and Technology Westinghouse Electric Corporation 19901 Germantown Road P.O. Box 355 Germantown, MD 20874 Pittsburgh, PA 15230 Mr. Ronald Simard, Director Mr. B. A. McIntyre Advanced Reactor Program Advanced Plant Safety & Licensing Nuclear Energy Institute Westinghouse Electric Corporation 1776 Eye Street, N.W.

Energy Systems Business Unit Suite 300 Box 355 Washington, DC 20006-3706 Pittsburgh, PA 15230 Ms. Lynn Connor Ms. Cindy L. Haag Doc-Search Associates Advanced Plant Safety & Licensing Post Office Box 34 Westinghouse Electric Corporation Cabin John, MD 20818 Energy Systems Business Unit Box 355 Mr. James E. Quinn, Projects Manager Pittsburgh, PA 15230 LMR and SBWR Programs GE Nuclear Energy i

Mr. M. D. Beaumont 175 Curtner Avenue, M/C 165 Nuclear and Advanced Technology Division San Jose, CA 95125 Westinghouse Electric Corporation One Montrose Metro Mr. Robert H. Buchholz 11921 Rockville Pike GE Nuclear Energy Suite 350 175 Curtner Avenue, MC-781 Rockville, MD 20852 San Jose, CA 95125 Mr. Sterling Franks Bartoa Z. Cowan, Esq.

U.S. Department of Energy Eckert Seamans Cherin & Mellott NE-50 600 Grant Street 42nd Floor 19901 Germantown Road Pittsburgh, PA 15219 Germantown, MD 20874 Mr. Ed Rodwell, Manager Mr. S. M. Modro PWR Design Certification Nuclear Systems Analysis Technologies Electric Power Research Institute Lockheed Idaho Technologies Company 3412 Hillview Avenue Post Office Box 1625 Palo Alto, CA 94303 Idaho Falls, ID 83415 Mr. Charles Thompson, Nuclear Engineer AP600 Certification NE-50 19901 Germantown Road Germantown, MD 20874

l t

WESTINGHOUSE AP600 SOURCE TERM MEETING ATTENDEES February 11 and 12, 1997 88HE ORGANIZATION JIM GROVER WESTINGHOUSE BRIAN MCINTYRE WESTINGHOUSE RUDOLPH SHER POLESTAR DAVID LEVER POLESTAR JUN LI POLESTAR JIM METCALF POLESTAR CHARLES THOMPSON DEPARTMENT OF ENERGY RICH EMCH NRR/DRPM/PERB JAY LEE NRR/DRPM/PERB DANA A. POWERS SANDIA NATIONAL LAB JACK KUDRICK NRR/DSSA/SCSB MIKE SN0DDERLY NRR/DSSA/SCSB J0E SEBROSKY NRR/DRPM/PDST ADDITIONAL PARTICIPANT FOR TELCON HELD ON February 12, 1997 HAME ORGANIZATION JIM SCOBEL WESTINGHOUSE DAN SPENCER WESTINGHOUSE J0EL WOODC0CK WESTINGHOUSE i

.s i

1 KEYISSUES i

FOR AEROSOL BEHAVIOR, TRANSPORT, AND REMOVAL IN AP600 CONTAINMENT FOLLOWING A DESIGN BASIS ACCIDENT c

(1)

Stratification and Mixing in the AP600 Containment i

Westinghouse position paper (No.2) in support of complete mixing (well-mixing) l of aerosols in the AP600 containment Aerosols are well-mixed in the atmosphere within the open compartments

[

that participate in natural circulation l

Develops natural convective circulation (rising plume) flow e

There will be hydrogen and non-condensible gases in the containment e

atmosphere h

o Little condensation is expected below the operating deck The IRWST compartment, accumulator rooms, CVS room and reactor j

8 cavity, and reactor coolant drain tank room should not be considered in the calculation of the aerosol removal l

t i

i

~

ISSUE 1 i

Are these new Westinghouse positions consistent with the current aerosol removal models (HYGRONAUA/STARNAUA) used in calculation of aerosol removal rates?

t I

y

i

)

k i

ISSUE 2 Westinghouse proposed a new accident sequence. A hot-leg break into the f

steam generator compartments with fission product and steam releases through the break and ADS stage 4.

1 Does Westinghouse still endorse the thermal / hydraulic boundary conditions and geometry data (1) provided in the Westinghouse response to RAI 470.27 (2/6/95) and in the revised response to RAI 470.27 (8/29/96), and (2) used during NRC/ Westinghouse source term meeting (8/29/94) and in Westinghouse position paper No.1 (8/5/96)?

l Boundary Conditions Geometry j

i Containment Temperature Containment Volume (Effective) l Containment Pressure Upward facing surface areas Steam Mole Fraction Vertical surface areas Condensation Rates Total Heat Transfer Rates 1

Steam / Hydrogen input rates l

l ISSUE 3 Single-compartment vs multi-compartment analysis ISSUE 4 Superheated conditions (and dry) in the containment atmosphere exist ISSUE 5 Re-suspension of deposited aerosol ISSUE 6 Nonspherical shape of aerosol particles ISSUE 7 Non-radioactive aerosol mass i

I l

[

F t

[

I l

STATUS AND

SUMMARY

OF WESTINGHOUSE DATA I

e SSAR, Section 15.6.5.3.2.2, Rev 0. dated June 26,1992 i

SSAR, Section 15.6.5.3.2.2, Rev 5. dated February 29,1996 i

t O to 5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months 0.35 per hour 5 to 5.5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months 1.3 per hour t

5 5.5 hours5.787037e-5 days 0.00139 hours 8.267196e-6 weeks 1.9025e-6 months 0.5 per hour i

i Neither technical justification nor reference given i

i i

i

~

e Letter from J.C.Devine to J. Wilson, " Passive ALWR Containment Natural Aerosol Removal," Section 4, "Results of AP600 Calculation," Leaver, D.E.

et al., August 29,1993.

O to 10.3 hr 0.49 per hour 10.3 to 11 hr 0.73 per hour

> 11 hr 0.52 per hour' f

?

NRC/ Westinghouse Source Term Meeting on August 29-30,1994 e

Leaver, D.E. et al., "AP600 Containment Natural Aerosol Removal," August i

1994 t

O to 2 hr 0.47 per hour 2 to 24 hr 0.64 per hour j

i i

L Westinghouse Position Paper (No.1) on the Removal of Aerosol from the e

AP600 Containment, August 5,1996 O to 2 hr 0.63 per hour 2 to 24 hr 0.81 per hour

[

Westinghouse Position Paper (No.2) on the Removal of Aerosol from the AP600 Containment, February 11,1997 New removal rates?

t i

4 SENSITIVITY ANALYSES OF AEROSOL BEHAVIOR IN THE AP600 REACTOR CONTAINMENT DURING THE 3BE DESIGN-BASIS ACCIDENT D.A. POWERS Sandia National Laboratories Albuquerque, NM February,1997

' MONTE CARLO UNCERTAINTY ANALYSES OF AEROSOL BEHAVIORIN THE AP600 REACTOR CONTAINMENT DURING 3BE DESIGN-BASIS ACCIDENT CONCLUDED:

o NAUAHYGROS " POINT" ESTIMATES FALL WITHIN UNCERTAINTY RANGE EARLY IN THE ACCIDENT LATE IN ACCIDENT NAUAHYGROS REMOVAL RATES o

ARE WELL ABOVE THE 90 PERCENTILE OF THE UNCERTAINTY RANGE o

LITTLE MASS REMAINS IN THE CONTAINMENT WHEN LARGE DISCREPANCIES DEVELOP BETWEEN THE NAUAHYGROS " POINT" ESTIMATES AND THE RANGE FOUNDIN THE MONTE CARLO UNCERTAINTY ANALYSIS.

o CONTAIN " POINT" ESTIMATES FALL NEAR THE MEDIAN OF THE UNCERTAINTY RANGE FOUND IN THE MONTE CARLO UNCERTAINTY ANALYSES.

4

- ne =

1

1. 5 m

n t.

90 PERCENTILE a:

t v

+

l-10 PERCENTILE i

z 4

w U

1. O 2

/s MEDIAN i

's l

s u.

s-s u.

s CONTAIN i

w s

a s

U s,

t z

s o

r i

L H

0. 5 g

N I

i x

z

,/

z l

1 1

x x

z l

N ' ~~.. A l--

o

/

i O

-/

i w

1 i

i c3 i

1 5

10 15 20 25

[

l t

TIME CHOURS) 1 I

Figure 2 Comparison of decontamination coefficients obtained in the uncenainty analyses and " point" values calculated with the CONTAIN code as functions of time.

\\

4 1

i L

s:

0. 4 l

l 8

l Q (TOTAL) /A l

O. 3 m

N

?I I

I I

[l l E

I O

i 3

s il i

' lg l

3 v

ia i

ig g Q (CONDENSATION) /A

,!fil, n x

0. 2 1

i 1

i i

a J

L. s 1

mg 1

w Lt.

gi h

1 in I

l--

t i g\\___,___-.--------

i 1 1 1

w I

0.1 s

t x;

1 4

'g l

.g a

a a a a

a a

a a a a

a a a a a a a

a a

l 2

4 6

8 10 12 14 16 18 20 22 24 TIME (HOURS)

Figure 4. Compariso'n of heat transfer rates to the containment walls by convection and by condensation.

i v

l

t t

i I

I I

I i

i i

I I

1. O

^z o

i-<m O. 8 r

zwaz i

o f

8 O. 6 J

a

)

i N

l

^z S

0. 4 i

(

H d

=

u w

L

0. 2 Lt i

au J

va l

I I

i i

1 1

I I

i I

I l

i i

l i

1 2

4 6

8 10 12 14.

16 18 20 22 24 TIME CHOURS) i i

i Figure 5. Ratio of heat transfer by convection to heat transfer by condensation.

}

4 t

I i

a

4-6 64,-awA ada2 s-*

J44u 4mau-Ah#-

J.#

+m-emV 4a5-Ja--4

e ddu4-b1a di-a-

-**-a-m-me

-m-r-

i-da t

6 i

t d

j d

j WATER VAPOR 5

i i

4 j

4 1

m b

a i

E U

3 s

3 v

E 4)

X Xo 2

o O

O O

=

1 O

I I

l i

300 400 500 600 TEMPERATURE (K)

a--

a a

n6.-=4

-me-rL-a s--414 4

--A-ama4

"--4-+A 449 A4 4 h J A---Aa.A r.

v

---.4w-+-,2,,a-p_s%A4_i,L_-4-~,sAA+Mzatu

..h rM r Kuau&=ma O

5 e

w AIR 5

i i

Be NB A

4 l

~

E U

3 s

3:

v E

.p

.E l

X o

2 oo m

1 G

g a

6 i

I I

300 400 500 600 TEMPERATURE (K)

l

)

AIR / STEAM 373 K

3. 5 l

\\

h

~

x

3. 0 s

O N

i 3:

1 v

f o

x X

oa o

l d

2. 5 4

1 1

1 i

' AIR HO 2

10 30 50 70 90 1

MOLE FRACTION STEAM e

4 J

1

.s WHY IS THERE NO HYDROGEN IN THIS PROBLEM ?

4.m..

4 m

..A w

_ _ _. _ _a_D..m 4

A-..

__A a

w.

m A,4.

J 42_.

A w.

.-ar e__

s

_a,a.

HYOROGEN 50 i

i i

i l

40 y

I g

U 30 s>

v E

-p

.X X

0 20 O

O O

O

~

10 I

I l

i i

300 400 500 600 TEMPERATURE (K)

T

w.

em..

.c

&4h.*o__

2a-.a.-.'m..9_.

4..m.4 a aww.:..A4

-we-m a sam a N. s+d-m a4 b

g e

AIR / HYDROGEN 373 K 25 i

i.i.i.i.i.i.i,i.

E e

e e

20 M

M 1

I E

U 15 s

g v

.p

_t X

~

o 10 o

o n

j 5

O e

a W

G l

I f

f I

f f

f AIR 10 30 50 70 90 H2 MOLE PERCENT HYDROGEN

4 CONTOUR PLOT FOR 10 kg (W/cm-K)

HYOROGEN O. 9 18 o, 9 h

b i

/O.7

0. 7 h

+

V G

U g

O. 5 O. 5 4g*

8-4

+

O. 3

0. 3,

0.1 4-0,1 AIR [,

3 HO 2

O.1

0. 3

0. 5

0. 7

0. 9 l

MOLE FRACTION STEAM e

o

CONTOUR PLOT FOR 104 kg (W/m-K)

O. 05 O.05 y

O. 04

3. 5 O. 04 z

o o

T T

a>-

o>-

I O.03 O.03 I

z z

o

3. 3 o

[

I o

u y

O. 02 O.02 y

u.

w

3. 2 w

_j

_J o

3. 1

3. 0

2. 8 o

I O. 01 -

O. 01 I

2. 5 AIR HO i

2 O. 1

0. 3

0. 5

0. 7

0. 9

. MOLE FRACTION STEAM

i i iinm iii,..

i,,,,,,,,

T (bulk) 6

=

w x

w z-m x

m v

m w

w s

x m

D Z

s o

x x

w m

a m

I w

w F

m w

r H

LAMINAR BUFFER.:

TURBULENT CORE T Geha)

~

' ' ' ' " ' i'

' ~ ' ' ' " " '

' ' ' " "r 10-3 O. 01 0.1 1

10 100 DISTANCE FROM WALL (cm) e W

1

(

i i

i T(bulk)

,=,-

=

/

n

/

M v

,f y

,/

tr a

LINEARIZED,,'

t s

cr w

n_

1 p

,f TURBULENCE MODEL i

,s

/

~'

T Csurface)

~

0.1

0. 2

0. 3

0. 4

0. 5 DISTANCE FROM WALL Cem)

i i

j BOUNDARY LAYER DEPLETION l

l i

i o THERMOPHORETIC (AND DIFFUSIOPHORETIC) MODELS j

OF AEROSOL DEPOSITION HAVE BEEN DEVELOPED FOR CONSTANT GRADIENTS.

o WHEN WE HAVE MORE COMPLICATED GRADIENT, SHOULD WE WORRY ABOUT DEPLETION OF THE BOUNDARY LAYER ?

o DO WE REALLY KNOW WHAT THE BOUNDARY LAYERS i

LOOK LIKE AND HOW THEY WILL AFFECT AEROSOL l

DEPOSITION ?

e 4

0. 60

3. 2 i

i i

i m

v.4 I c

.I NAUAHYGROS

^

v m

/

N

-Q w

f

$ 0. 50

3. 0 v u

W

~

+

1 k

M wa z

o o

0. 40 z

2. 8 [

o

~

m

+

z W

z o

z z

o MONTE o

I- 0.30

2. 6 z

CARLO 2

o u

W W

+

o m

1 I

I I

I i

l i

I i

iil i

9 11 13 15 17 19 21 23 25 TIME CHOURS)

Figure 1. Comparison of the steam condensation rate and the aerosol deposition rates predicted by the NAUAHYGROS code and the model used for the Monte Carlo uncertainty assessment.

3 1

i SENSITIVITY ANALYSES 1

I UNDERTAKEN TO IDENTIFY THE SOURCE OF THE o

DISCREPANCY BETWEEN NAUAHYGROS AND THE j

MONTE CARLO ANALYSES AT LATE TIMES IN THE j-3BE ACCIDENT.

e i

o VARIATION OF ONE PARAMETER AT A TIME.

i o

INTERROGATE THE EFFECT ON THE RATIO:

i l

1 l

Vo(th)/V (diff) o i

\\

5 WHERE i

l Vo(th) = THERMOPHORETIC DEPOSITION l

VELOCITY i

Vo(diff) = DIFFUSIOPHORETIC DEPOSITION VELOCITY

DEPOSITION VELOCITIES V (th) = [2C, p /

g XPg] [k /k + C Kn] CVinT D

gp t

[1+3C Kn] [1 + 2k / k + 2C Kn]

m g

p t

V (diff) = { 1 +(Col 2 x)( 1 - X[H 0])} D[H O) VX[H 0] /(1 - X[H 0])

D

/

2 2

Kn = Knudsen number 2

2 2

3 C = 15 + 12C Kn + 9(Ci + 1)Kn + 18C (Ci + 2)Kn t

2 2

2 15 - 3C Kn + C (8 + xa )(Ct + 2)Kn i

2 t

C = (2 - u )/"m i

m C = 1/(2 -a )

2 m

C, = 0.75 (1-a ) + 3 amE(5) m C = 15 (2 - a ) [5(1-a )/(x)/8 + a ((t)]/8a t

t t

Cm = [2 - a ) [0.5(1 - a )/(K) + "m ((m)]/a m

m m

am = momentum accommodation coefficient a = energy accommodation coefficient t

012 = scattering kemel X[H 0] = mole fraction steam 2

x = dynamic shape factor of the particle

. =

p 4

o 4

g s,

\\

's

\\

i s

\\

's

\\

's 4

's, C

g

\\

's g

s,

\\

's, F

Z N

's W

\\

% C s,

m ama men M

s s

%g g

N

\\

,i W

g N

O 2

s s

1 s

E D

's l

m

's C

N-1 W

M m

i i

i I

I I

I O.1

0. 3

0. 5

0. 7

0. 9 ACCOMMODATION COEFFICIENT (-)

O M

r

- e

~"

O. 9 X D(th)p IE VInT CONTOURS g

V g

g

,/ -

y O. 3 o

t D. 7 n

l O

l 0

l Z

O

0. 4

0. 5 p

i a

/

O 2

o'/_

,/

5

/

,/

0. 3 8

o

,/

0.' 6 Q

,/

-D...-_

g 7

O.1 52 g

'l

,/

i -.

i i

g 0.1

0. 3

0. 5

0. 7

0. 9 MOMENTOM ACCOMMODATION COEFFICIENT, a ni

m..

EFFECT OF GEOMETRIC STANDARD DEVIATION

.. i i i i i i i i i.. i..... i i, i i i

1. 0 4

A

~

C

0. 8 w

3 i

00.6 3v N

A a

50.4 cr = 3. 0 g

o AS CALCULATED i

'V

1. 6 s

0. 2

- ^-

^

f*

f I

f 9 t t

I t

t t

t i

f f

f 'f f

t i

I t

t 2

4 6

8 10 12 14 16 18 20 22 24 i

4 s

TIME (HOURS)

EFFECT OF MEAN PARTICLE SIZE

]

i i + i i i i i i..........,....

l.

1. 0 j

~

A 4

C

0. 8 w

3 00.6 3v N

A n

f O. 4

0. 7x

a AS CALCULATED

~

a'

\\

1.3x

~

v

0. 2

//' -

Q.... '

f I

f t

t t

t I

t iI t

f t

t t

t Y

f f

f 2

4 6

8 10 12 '14 16 18 20 22 24 T!ME (HOURS)

Figure 10. Effects of panicle size distribution parameters on the relative contributions of therrnophoretic deposition and diffusiophoretic deposition.

18

EFFECT OF PARTICLE THERMAL CONDUCTIVITY i

i i

1. O Ag O. 8 w

m v

0 0. 6 3vx

~4

^

kth (W/cm-K) = 6.3x10 o

m

-3 o

C

0. 4 6.3x10 l

d O. 63 i

O

~

fI I

~

\\

v 1

i--

(/

O. 2 I

snt f g~~~_-_-_--__________-

l l

2 4

6 8

10 12 14 16 18 20 22 24 TIME (HOURS)

Figure i1. Effect of the thennal conductivity of the acrosol particles on the relative rates of thermophoretic and diffusiophoretic deposition.

1 PARTICLE SHAPE FACTORS I

o POORLY KNOWN FOR AEROSOLS PRODUCED IN REACTOR ACCIDENTS o ASSUMING SHAPE FACTORS TO BE 1 AMOUNTS TO ASSUMING THAT THE PARTICLES ARE PERFECTLY SMOOTH, PERFECTLY DENSE SPHERES

- THEY AREN'T t

o SHAPE FACTORS

-INCREASE TO AN ASYMPTOTE WITH INCREASING PARTICLE SIZE

- ARE SMALLER AT VERY HIGH HUMIDITY

- ARE PROBABLY AFFECTED BY ELECTROSTATIC CHARGE 1

o SHAPE FACTORS HAVE BEEN MODELED IN TERMS OF THE FRACTAL DIMENSION OF THE PARTICLES g

m-

+

4 l

h Physical Phenomena 1

i d

i 1,

i

~

1 t

2. 0 i

i 2

l 1

______x____________________.

X v X

X&

2 ex i

X X

x QUADRUPLETS o

X

______{.___.

I--

U Lt.

--____y____________________

b:.#

W 4

Q-TRIPLETS i

<1 1= 5 W

i

.---Q ge--------------------

^

U i

I 20 1

c 0

0 DOUBLETS Ob O

N'

._________________________a t

i i

1. 0 O. 5

1. 0

1. 5 i

KNUDSEN NUMBER Figure 86. Dynamic shape factors for doublets, triplets, and quadruplet agglomerates of s particles. Solid lines indicate mean values. Dashed lines define 95 percent confidence i

bounds.

189 NUREG/CR 6153

i I

i i

iiiiiiiiiiiiiiiiiiiii

1. O A

C

0. 8 lb, 4

i v

v

0. 6 ll l

INTERNAL

>y CONOENSATION x

ji :

^

nj

0. 4 li,'l

l v

NO INTERNAL O

I a

jgj;g CONOENSATION v

4.i::;:

/,_,..,___ '

O. 2 i,

r

~

~)

H I

I I

I l

l 1

1 I

I I

f I

I I

2 4

6 8

10 12 14 16 18 20 22 24 TIME (HOURS)

Figure 9. Effect of internal condensation on the deposition velocity due to thermophoresis relative to diffusiophoresis.

100 i

i i

i

\\

g 80 v

3 l--

g o

60 7

1a r

s 40 H

1

-J w

E 20 l

l t

i I

I I

i i

f f

i i

1 2

4 6

8 10 12 14 16 18 20 22 24 t

L TIME CHOURS) i Figure 7. Relative humidity in the bulk containment atmosphere.

l I

1' 4 >

Y e

9

~

9 I

i

~

0

~

i

~

I

)

1

~

S/

Y S

i R

~

7

(

~

I U

0 E

O

~

C H

~

N i

2

~2 I

A 2 ~~

T

~~1 S

~

I 5

i

~

I D

S' 0

~

2

,R S

r

'U S

e f

O H

1 E

s i

n L

a m

~

N r

t

~.~

s 6

O s

~

a I

3 m

~ -

=

S i

1

~

r

~

s t

0 N

o f

.s E

r M

ey i

' ~ ~

I a

l i

D yr a

d nu 1

o i

~. -

I b

O e

,~.

h t

ss orca 0

0 0

y 9

7 5

3 1

i t

d i

mu h

n n v > s O s-<7oI W> $J_Wg ev i

ta leR 8

eru g

iF u

~

l

)

^'

},

e C

M

^

k g#

3,

^

t Tf 7

2; u

E

\\

i l

Figure 6. Fractal product of a two-dimensional simulation of particle agglomeration.

e m

Table 1. Fractal Dimensions of Some Aerosol Particles 4

Investigators Fractal Dimension

Method Remarks Forrest & Witten 1.5 tol.7 expt.

Inorganic mat'Is, Meakin 1.4 tol.45 analysis Richter

<2.4 analysis Feder et al.

<2.3 expt.

Carbon black Martin et al.

1.84t0.08 4

expt.

Mountain et al.

1.7 to 1.9 analysis Samson et al.

1.5 to 1.6 expt.

Hurd & Fowler 1.4910.15 expt.

Flame generated silica particles Zhang et al.

1.72*0.10 expt.

Mulholland et al.

2.07 0.08 analysis 1.89 0.08 I'

Lesaffre 1.52 to 1.57 expt.

13.3% RH TiO2 1.71 to 1.83 87.4% RH TiO2 Meakin et al.

1.8 to 2.12 analysis Megaridis & Dobbins 1.62 tol.74 expt.

Charalampopoulos &

l.7 0.08 expt.

Chang

a fully dense sphere has fractal dimension 3 4

10 4

EFFECT OF FRACTAL DIMENSION i

e i

i i

e i

i i

i e

i i

e i

1. 0 A

0. 8

^w 4

~

U v

O O. 6 V

N

/w

^

n O

j

0. 4

[i[

l.

dp = 2.25 1.76 v

a i

1.45 V

0. 2

,a l :,.;!

_ljki,::,,( 'IM

_ _ ' ' ~ - - -

e p,

%,j'

^\\

"1 1

I I

I l

I i

I I

l i

I I

2 4

6 8

10 12 14 16 18 20 22 24 TIME CHOURS)

L i

l Figure 12. I!ffect of the fractal dimension of the acrosol particles on the relative rates of acrosol deposition by thermophoresis i

and diffusiophoresis.

I

EFFECT OF PRIMARY PARTICLE SIZE 1

I I

i I

i i

I I

i

1. O dp = 1.76 r

0. 8

^

4 4

t n

o v

O O. 6 V

N

's e.

A U

n u/

j d (pr4 = 0.10um

[

j O. 4 0.02um a

0.005um v

1:-l *l *h i

O. 2 4

g, ;', n

..,.,.y,i ~ ~,

, U,,,

r

., g s

e

i..<

iri i

i i vi

Ti i

i __ _i i

i i

i r1 t

2 4

6 8

10 12 14 16 18 20 22 24 i

TIME CHOURS) t 1

Figure 13. Effect of the primary particic size on the relative rates of thermophoretic deposition and diffusiophoretic deposition.

e i

p CONCLUSIONS THE DISCREPANCIES BETWEEN NAUAHYGROS AND o

i THE MONTE CARLO UNCERTAINTY ANALYSES COMES

{

ABOUT BECAUSE SHAPE FACTORS ARE TAKEN TO BE i

THOSE FOR PERFECTLY SMOOTH, PERFECTLY DENSE SPHERES IN THE NAUAHYGROS CALCULATIONS. THIS IS 1

NOT REALISTIC. IT RESULTS IN THE OVER-EMPHASIS l

OF THERMOPHORETIC DEPOSITION.

- NEGLECT OF SHAPE FACTORS WILL ALSO OVER EMPHASIZE GRAVITATION SETTLING.

4 l

o OTHER QUANDARIES ARISE:

- SHOULD HYDROGENBEINCLUDED IN THE ATMOSPHERE ?

\\

- DO WE HA VE TO WORRY ABOUT BOUNDARY LA YER DEPLETION ?

-IS THE WELL-MIXED ASSUMPTION ADEQUATE ?

e-

,,--r w,,..--.---rem

.----..r--r e..

.-m

.,.----*---.-,y

,r-.

v

...m,---..--,e--m i,-.--,%

i r

l c.,4 i

l

,-c,.

e

. y.,. 2 y-l lli g

rf..y./ y.-

-,.e..

w

~,..

,,,u....

ii

g f-

_v.

~

,.y-a-

l p

s,,,

~,,

, y -

,.. z.,,

l

( j<.rs L.( :

/ f t'*, ).~$

~ 7~ > l

=

f wp, /

/ w y.k w ow i L. 'r e 7

~ > <

o p,.,

w e.c i

p f.

p 7 y<.,

l c~

s;r.,

2.

'J --

my w,nep

,. er>-

7c" L,r *

t s-?- y~~p f { ).~ - i.A.(, /,o y 1 l

i

)7>c m /n ( '

{ )J fop w> i-,~J *f o c.4 7 y'=r va.

y y,3 y* f far a~ p _./.,ss~ ~

4**

.m *y w orp

?nr' "7 '. y p y r*'.)

=

y442O yJ'teU % p i

i f

i I

A.s:ruw V.-

4.s xso e w 3 P=

er at t

7~=

3 70 k EEE Yeor Co.,)ain pereesl lr a 3 A X /b Jer oles ya s

agg s

l 503 b esl ts

/0O boro lesfg lS00 f lE y

w1.1%

x n /<.= 7 m a., 4 y Joa

-/s, R j'

}

fu - <-

va /u - e

)=

fo ao ne /--/.s f

h-<

l Ma my 4

L i

3x Jo hs J\\ooo s 7 o n a m. l a.s S

folrah

.3>*s T sse essierf e

e O

NRC/ Westinghouse

\\

AP600 CONTAINMENT NATURAL AEROSOL REMOVAL Prepared for Westinghouse and NRC Dr. David E. Leaver Dr. Jun Li Dr. Rudy Sher i

i POLESTAR APPLIED TECHNOLOGY, INC.

1 First STREET, SUITE 4 f

LOs AI;rOs CA 94022 l

l February 11,1997 j

\\

5y POLESTAR APPLIED "l'ECHNOLOGY, INC.

2/11/97 1 i

~

NRC/ Westinghouse Items for Discussion (from NRC Letter, Jan.10,1997) r

1. STARNAUA Evolution and V&V

2. Sensitivity Analyses

3. Nodalization

4. Rationale for Well-Mixed Containment Assumption

5. Summary of Experimental Data and Literature

6. Technical Basis for AP600 Lambda Results l

7. Lambda Uncertainty Distribution

8. Boundary Layer Effects i

1 POLESTAR APPLIED TECHNOLOGY, INC.

2/11/97 2

NRC/ Westinghouse l

[

Discussion items 1 and 5 STARNAUA Evolution, Validation, and Summary of Experiments and Literature Evolution of Code Development l

Validation of STARNAUA (NAUA Mod 4, LACE, NAUAHYGROS, Talbot model comparison with experiment)

Additional experiments and literature (DEMONA, NSPP

. cs -

ORNL, comparison with TRAPMELT, additional thermop..oresis j

experiments, Goldsmith thermophoresis + diffusiophoresis) l 4

i i

POLESTAR APPLIED TECHNOLOGY, INC.

2/11/97

s i

Evolu of Code Development n.. (

i; NAUA mod-5 (1987)

'e

\\

diffusiophoresis NAUA mod-4 (1983) i i

particle agglomeration gravitational sedimentation %

steam condensation j

i on particles in super-saturated atmosphere STCP

. diffusiophoresis spray removal v

NAUAHYGROS (1985-1994)

EPRI - Stanford - VTT(Finland) i improved treatment of steam condensation on walls

}

and on particles hygroscopicity j

multi-component aerosol, moving bin boundaries extensive revisions to code structure and T/H inputs l

i v

STARNAUA (1994- )

Polestar Applied Technology

)

thermophoresis and spray removal models Q-A; V/V l

(mod-4, NAUAHYGROS, separate effects exp., etc.)

a

NRC/ Westinghouse

{

Validation of STARNAUA Tests in vessels simulating containment geometries show that aerosol is removed by a combination of natural processes including gravitational sedimentation and diffusiophoresis In addition, laboratory tests have been performed which demonstrate that thermophoresis contributes to aerosol removal l

when there are temperature gradients at heat sink surfaces (e.g.,

l the containment walls) i These processes (including effects of particle agglomeration) are modeled in STARNAUA Validation of STARNAUA:

- Sedimentation validation: STARNAUA compared against NAUA Mod 4 (dry)

- Diffusiophoresis validation: STARNAUA compared against NAUAHYGROS, NAUAHYGROS compared against LACE

- Thermophoresis validation: STARNAUA model (Talbot equation) prediction compared against several laboratory i

experiments i

POLESTAR APPLIED TECHNOLOGY, INC.

2/11/97 4

NRC/ Westinghouse Sedimentation l

I i

108 Vsed =

r C (K )

i n

n 9M i

I

?

POLESTAR APPLIED TECHNOLOGY, INC.

2/11/97 7 i

.-=

VALIDATION OF STARNAUA AGAINST NAUA MOD-4 i

i h

g's

\\

s Ch

-\\

t P;

y..

t

,,e ETNtdevA b"

i h

av "Le -

"r "te yie,,-

i Figure 1. Sample problem 1 - abbome and totalleaked masses.

t nud a g,. e nud 3 J

6**

nud s v...,

Eh I

w 9

musua 9g_

o k

b

-' v

~e ir

~r gir,,

i i

i Figure 2. Sample problem 1 - leaked masses by nuclide.

O i

VALIDATION OF STARNAUA AGAINST NAUA MOD-4 s

5 5

^

5

/h

+

/,

m \\

{

<rravauA

\\

k

. io.

. 3,.

T1E (3)

Figure 3. Sample problem 1 - average particle radius.

l i

i 9

t 4

1 NRC/ Westinghouse t

Diffusiophoresis Stefan flow diffusiophoretic velocity i

X M

W s

s 77 I)

YI ahs l

s s

a l

l Independent of particle size f

f t

\\

POLESTAR APPLIED TECHNOLOGY, INC.

2/11/97 5 i-l l

i

NRC/ Westinghouse f

NAUAHYGROS Against LACE i

LWR Aerosol Containment Experiments (LACE) performed at Hanford under IPRI organized, international sponsorship including NRC Used a large (850 m3) tank with steam-air mixture Used two aerosol species (MnO, CsOH)

Aerosol injection times (~1 hr) and peak aerosol concentrations (~1 - 5 i

g/m3) typical of severe accident conditions Measurements included suspended aerosol concentration vs. time, sedimented mass, plated mass, leaked mass, aeroso! size, and l

thermal-hydraulics l

Results indicate good agreement between measured and calculated plated masses l

i POLESTAR APPLIED TECHNOLOGY, INC.

l 2/11/97 5 t

I

I k

ORNL nWG 38-203 i

+ 11.03m ELEV.

TURBIDITY /

UPPER j

PHOTOMETER O

(2 LOCATIONSI FM 4:"

_rO 9 TO STACK O

O

?bY:

n SCRUB 8ER E

TO BYPASS

{

J SCRUBBER l

h AEROSOL C

MIXING WINDOW VESSEL 3 (TYP OF 21

[

AEROSOL CESIUM VAPOR-DELIVERY PIPE

/

ta NITROGEN-X 200 m m STEAM],,,

g I

PLASMA r4__.--

=

TORCHES M ( -

p 7 TV

,)

Mn POWDER CAMERA

(

/

p

/

ORIFICE O FILTER CLUSTER l

,/

g

'TO STACK TTW SAMPLE STATION kpg h (7TOTAll 40 1

g WALL CONDENSATE O

M COLLECTOR (4 TOTAll O

1 3~

g i

j y,_! hj SCRUBBER FM FLOWMETER y

pd VALVE STEAM i

3.30 m ELEV.

Fig. 1.

Experimental setup for LACE test LA2.

i e

s j

i LACE VALIDATION -

SUSPENDED MASS 4

i CONC., TEST LA-2 i

i 1

l h

l 4

3.5 -

Test data E_

3 Cdculated b.5 2

l N2 5

/

\\

j of i

a 1.5 -

l 1

l /

\\

3' W X

0' il

.N O

l 0

5000 10000 15000 20000 Time (sec)

I 1

l l

l I,

E f

l_ ACE VALIDATION -

l SUSPENDED MASS i-l CONC., TEST LA-4 1

I i

l l

5.

i-4'5 :-

e e e

Test data 4

A

_(

j

[

$e Calculated 45 i 7

\\

g 3:

/

\\

82.5.

l 4

=

J

\\*

a 2.

x i

E

/

\\

h

! /

\\

en 1-4 m

3 /

N 0.5 g7 4

0 i

O 5000 10000 15000 20000 i

T1nne (sec)

)

i LACE VALIDATION -

l SUSPENDED MASS l

CONC., TEST LA-6 i

4 l

1 i

l 4~

l Test dato i

3;

/

Calculated 1

e 1

ll 2.5 :l/

\\

i 2

l E

e

- 1.5 -

j 0.5 v

O~

j 0

5000 10000 15000 20000 Time (sec) 4

)

I i

i f

I

Table 1.

Integrated settled, plated, and leaked aerosol, Tests LA-2 AND.LA-4 i

l i

Settled (q)l.: Plated (g)

Leaked (g) t LA-2, test data 1973(* 10%:)

449(* 20%)

1515(* 15%)

LA-2, calculated 2366 334 1197 LA-4, test data' 4490(

10%),

532(

~20%)

108(

30%)

LA-4, calculated 4437 609 96 l

LA-4, calc. w/o steam 4811

~10 321 I

h t

f l

i 1

i I

t t

I

VALIDATION OF STARNAUA AGAINST NAUAHYGROS J

Table 2. Comparison of STARNAUA and NAUAHYOROS (357 seconds totals).

i NAUAHYOROS STARNAUA Airbome H O mass,kg 55.3 55.5 2

j k

Airborne dry mass,kg 60.6 60.8 Airbome

)

CsOH mass,kg 34.6 34.7 Airbome 2

MNO mass,kg 17.3 17.4 Leaked H2O mass, g 0.90 0.84 Leaked dry mass, g 0.63 0.64 t

Tota) sedimented mass, g 109 106 Total diffused mass, g 2004 1806 i

Ammd, m 1.917 1.917 Geom. std. dev.

1.888 1.888

._. _ _. _ _ _ _ _ - _ _ _ _.. _ _ _ _ _ _ _ _ _ _ _ _ _. _ _ _. _. ~. _. _.

NRC/ Westinghouse Thermophoresis Thermophoretic velocity i

t 2C C (K )4(r) dT V

=

th pT dx l

l a + C Kn 4(r)= (1 + 2(a + C Kn))(1 + 3C Kn) t m

C

= 1.17 s

C = 2.18 t

i C

= 1.14 j

m t

i Independent of particle size up to approx. 0.5 micron j

Temperature gradient can be replace by sensible heat removal rate j

POLESTAR APPLIED TECHNOLOGY, INC.

l 2/11/97 6 t

i

~. -

a 4

VALIDATION OF STARNAUA THERMOPHORESIS MODEL (TALBOT EQUATION)

COMPARISON WITH EXPERIMENTAL DATA U,kan b Tah d ; M V-o) 12 4 i

i 10 4 (c)

Waldmann 4

(/)

(')

(6)

{84 g,,

E

- o 2

4 o

x 64 p

o I

b i

?

-t o

- f l/

F E.

0 t 44 il 0

-t l i

l 24 J /,

'I (d) l 4

O l

2 3

4 5

KIA Faccaz 6. Reduced thengophoretic force as a function of Knudsen number. Data: O. Schadt &

Cadle. Hg:

. Schadt & Cadle. TCP: ---. Schmitt, silicone oil. Analytical resulta:

i equation (15) (a) Schadt & Cadle data. (6) Schmitt data

. Epstein fonnula, equation (1).

(c) Schmitt data. (d) Schadt & Cadle data -

. Derjaguin et al. (1976), from equation (11).

(s) oil droplete. (f) Nacl.

Figure 6. Comparison of Talbot equation and experimental data.

s

y --

162 L. Talbot, R. K. Cheng, R. W. Schefer and D. R. Willis 1

l 3

i i

(c) pp p ".$?o e

,p.

o O

l e,'s

. O

~

h

/

O g

Waldmann

~ ~ ~ " - -

1 (b) 05 I

I 1

1 1

i 0

I 2

3 A/R Frauns 7. Thermophoretic velocity as a function of Knudsen number. Analytical results:

. equation (16). (a) oil droplets, (6) Nacl; ---- equation (17), (c) oil droplets; (d) Nacl.

O, Derjaguin et al. (1976), Nacl; e, Derjaguin et al. (1976), oil droplets; A, Prodi et al. (1979),

Nacl.

Comparison can also be made with the data of Derjaguin et al. (1966,1976) on oil and Nacl aerosols. These authors report their results in terms of the thermophoretic velocity Ur as shown in figure 7, which is a replot of figure 2 of their paper. Also plotted for comparison are curves giving UrT,/vVT according to (16) and (17). It is seen that these data are in better agreement with the Derjaguin et al. correlation than with the presently proposed fitting formula. The fact that their U data fall for the most part J

r considerably above the collisionless limit implies that the corresponding thermal forces exceed Fr.. In fact, if we insert the expression for Ur given by (17) into the Millikan drag formula, we obtain the curves shown in figure 6 identified as Derjaguin et al. (1976). However, as an additional comparison, we have also plotted in figure 7 the thermophoretic velocity data of Prodi et al. (1979) obtained with Nacl particles. It is seen that these data agree exceedingly well with our fitting formula (10).

-[

Evidently, the data of Derjaguin et al. are in substantial disagreement with the

}

Schmitt and Schadt & Cadle data. The correlation formula (17) would appear to have incorrect behaviour for large A/R since it predicts velocities (and forces) nearly double the collisionless limit values. It is not clear from the information given in their paper how Derjaguin et al. (1966) determined the size and speed of fall of their aerosol droplets. The Basset formula, the use of which is implied in the paper by Derjaguin & Yalamov (1965), becomes inaccurate for A/R 2 01, and this in fact, as

{

noted earlier, fixes the range of validity of the self-consistent hydrodynamic theory.

Since, as we have already observed, results such as (17) which derive from arguments l

based on irreversible thermodynamics cannot in principle yield information beyond that obtained from Navier-Stokes theory, the range of validity of (17) might also be expected to be 0 < A/R 5 01. From a comparison of their correlation formula

..,n

I

k A A i h.J Eqi..~ b 4.,J L.fm b N AVA meo 4g Ac4iw: r DEMowA

..~.r-10*

~

g

-- g.

m 10'

//

h,'

?

f f

,s

~

\\

c

~

J.i

/s O

\\1 O

/

1:c 10o

,/

//

/

T.

o y

2 c

O

/

O

,.f,

\\\\

4 l 5 e

M g

vi I

t O

i ASTEN 4

E i 0.s

---~~ ENEL i

t e

a c

-+

. ORS s

0 i

4

. JRc-B

.a

~

s.

-... -.- JRC-R g

g

.g.

--- Kf K

!j, ji

((

. gi

- RNL k k

, I, 10-2

SEAD i.

g

{1 5

3

-~~~ SRD

{i, k

SwEC i

'q

...-. UPM

.f jf y*

9 experiment 8

s.

11 10-2

.."1 i.

i>'"

2 2

5 10' 10 10 10' see 10 time Fig.1: Calculated airborne mass concentrations compared to experimental results.

1 l

ORNL-DWG 86-5401 ETD i

1 ACCESS FLANGE J

I 1

I

[

5 W EXHAUST TO FILTERS

}

i l

[?t3 M v COMPRESSER AIR / VACUUM LINE A

j STEAM

.h.

f TRAP INVESSEL I

i PLATEOUT RATE SAMPLER l

l AEROSOL

-4 d

SAMPLER (4) k l

TOTAL PLATEOUT SAMPLER (4)

STEAM f

FLOW

' WALL AEROSOL PLASMA TORCH AEROSOL

\\f\\

Ul 9

METERING SAMPLER (3)

POWER 7

f STEAM SUPPLY y

j TRAP INVESSEL 3

C ::

M CASCADE I

i IMPACTOR (2)

STEAM CONDENSATION -- COMPRESSER AIR /

q 1

SAMPLER

VACUUM LINE g

CASCADr P

p I'*

+

~

PLE AUX-SPIRAL CENTRIFUGE g

u SAMPLING & SAMPLER W

--4

% ELECTROSTATIC S

F l

F AN-MIXE R AEROSOL SAMPLER g

FALLOUT A@

I STEAM SUPPLY 1

.O RATE SAMPLER r

=,

d

[

TOTAL FALLOUT SAMPLER (6) l -

- WElGH TANK AND WASTE TO STEAM CONDENSATE SYSTEM j

Fig. 1.

Schetnatic of Nuclear Safety Pilot Plant (NSPP) Facility.

{

i i

.m 1

e 18 4

N $PV ktN'f0l ORNL-DWG 86-5402 ETD 4

i t"

t m

1 m

s 6

i Ze o

E<

1 l

1 h

=

I U

xb O*

u A

i w

a i

A Z

i m

4 ho 8

8 j

i pH M

=

I 1

l b_

N. - _.._..

i 4

l i

b.

4

- 1d Id Id 16 TIME, min i

j Fig. 3.

Average aerosol mass concentration - NSPP Test 501.

i i

t a

a 4

1/22/97 e4 J J. b. _J E p.... b < > L ib r b r_

Comparison of STARNAUA and TRAPMELT thermophorests models r

1 --

g N

e Q

g F s, 4

D

\\,.

E 2

s '.s Ea 0.1 --

N'.'>,

s-

\\'.N.

'O TRAPMELT, alpha =

('. ' -

o y s

'Ei

.001 N

's - s s'N

's.

e 3

- - - - - TRAPMELT, alpha =

N 's s

'Di

,01 s

o 0.01 --

- - - - - - - - STARNAUA, alpha =

N.

'O

.001 h

\\

1,

- - - - - STARNAUA, alpha =

.l

.01 o5 0.001 l

l l

l 0.001 0.01 0.1 1

10 100 particle diameter, micrometers S

4.,a4 a4Ju4

,.W

.smes.m-46E&2

-4.hm.(44da

-dd.-.m JMA

,M 4%N+5#afe e s4 5

-Fd.r*+-*ir,.ama m,

ep.

a d

wa%

4,4 s.

m

'e f. L 4

M..,

- 8 o

+

4, 4

d i TT

~

..=

~

M k

t o

,q } %

E

~

Q u.

2%

o o

{

e w

O o.

7 Ud

~

I t

m i

f i

t o

os

.l.

t o

60 F

o-K J

?

$1 c

t t

S

<e. d

)

o

~

o J

5

_c O

1 o

8

./

I h.

M-o g

u o

0 1

m T

e

.e y

4 1

e g

x Q

d Y

Q 2

!1 !

l

,l

\\

t I

I I

g o

o o

D o.o o

o o

m g. 4 N

O to 4

4 N

el gh

[

M0lDo'3 ng(sx + ox )1g z

i i

.p.

d ui b J E,.,.... - b

.,,1 L.T.~6.n 4

E Cn e. V 3 m N ( l H. 4 )

J

! lone and for diffusiophoresis alone, based on the results given in Sections

~

I and 3.2. For the estimate of diffusiopfloresis the water-vapour pressure I radient corresponding to a given temperature gradient was calculated from

se temperature of the two walls and a knowledge of water-vapour pressure 4

o 80 j

oos i

048 f

i o47 g

006 5

}

Icos

[

/

44 po\\

043 oct l

0 01 4

o 1 2 3 4 5 6 7 8 9 to il 12 13 14 15 16 17 18 Normalized thermo! gradient y 6 *K/cm c.11. Velocity of particles in superimposed thermal and water-vapour pressure gradied -

triati ns over saturated salt as a function of temperature. The cont!nuous se marked " thermal plus diffusiophoresis curve" is the sum of these two dividual curves. It is in excellent agreement with the experimental points ad demonstrates impressively that thermophoretic and diffusiophoretic 1rces are additive. Similar results have been obtained in air also.

6. Sous EFFECU OF SUPERSATURATION In the crevious exoeriments described in sentinn 5. =aturatea cait enin+ine

I NRC/ Westinghouse

\\

[

Discussion item 6 Technical Basis for AP600 Lambda Results l

1

?

STARNAUA used for aerosol calculation j

l

- Validated aerosol code which is maintained.under Polestar App. B QA Program

- Includes agglomeration, sedimentation, diffusiophoresis, and thermophoresis and is based on models which are widely j

used and accepted in the international safety community Source term inputs based on NUREG 1465, and plant design input based on AP600 design Calculate aerosol removal and associated lambda vs. time, j

leaked mass vs. time, and removed mass vs. time Perform sensitivity analyses (Discussion item 2)

I I

POLESTAR APPLIED TECHNOLOGY, INC.

2/11/97 6 1

. ~. _ _. _ _.

l

(

NRC/ Westinghouse

[

Define Source Term and AP600 Design Specific Inputs Source Term inputs

- Consider early in-vessel release

- Gap release assumed to begin at time of core uncovery

- Final NUREG 1465 release and timing used for all radionuclides except low l

volatiles (Sr group, La group, Ce group)

- Aerosol size distribution r =0.22 micron, sigma =1.81 g

- Inert to fission product ratio = 3:1

- Average particle density 4.7 g/cm3 j

- Shape factor 1.3 AP600 Design Specific inputs a

2

- Containment volume = 45,797 m, sedimentation area = 3500 m

- Aerosol well mixed in open parts of containment (open parts of containment do not include IRWST, accumulator rooms [i.e., valve vaults], CVCS room,

(

or reactor cavity [ including reactor coolant drain tank room])

- Containment leak rate = 0.12 vol %/ day

- Plant specific thermal-hydraulics (see subsequent slides) l l

POLESTAR APPLIED TECHNOLOGY, INC.

2/11/97 7 I

AP600 Accident Sequence Classes (from AP600 PRA, Rev. 8)

Frequency Contribution Time of Core Approx. Time Time of Vessel Accident Class (yr1)1 to Total CDF' Uncovery (hr) of Reflood (hr)

Failure (hr) 1A (Transient or RCS leak, 1.8E-9 1%

1.6 8

N/A ADS and PRHR failure) 1AP (Small LOCA, ADS 3.2E-9 1.9%

20 30 N/A failure) 3BE (RCS fully depressurized, 7.8E-8 46%

0.7 2

N/A gravity injection failure)

[

3BL (RCS fully depressurized, 4.4E-8 26%

6 N/A N/A gravity injection success, recirculation failure) 3BR (Large LOCA, 7.7E-9 4.6%

0+

0.1 N/A accumulator failure) 3C (Vessel rupture) 1.0E-8 5.9%

0+

0.1 0

3A (ATWS) 1.0E-8 5.9%

N/A N/A N/A 3D+1D (Transient or small 6.2E-9 3.6%

0.8 2

N/A LOCA, partial ADS; or medium LOCA, ADS failure) 6E+6L (Steam generator tube 8.7E-9 5.1%

12 17 N/A rupture, ADS failure or recirculation failure) e i

h

NRC. westinghouse f

AP600 Thermal Hydraulics Calculation MAAP results for Accident Class 3BE are used for thermal hydraulics j

Information obtained from MAAP includes:

l

- Containment gas temperature as a function of time

- Containment pressure as a function of time

- Mole fraction of steam in the containment as a function of time

- Condensation rate vs. time

- Total heat removal rate as a function of time i

f t

POLESTAR APPLIED TECHNOLOGY, INC.

2/11/97 9 1

i

~-.

.= --.

t Containment Pressure & Temperature 4

160

,q 140

~ 5 3.5 Pmssure

{;'

{

,v s

120 3

\\

2.5 100 m

'I 2

E 80

.m N

g 1.5 60 1

40 0.5 20 0

0 0

20000 40000 60000 80000 100000 Time (seconds)

!l

,l l!.

l;il l!!l!t!;

00 000 1

0 0

8 y

0

)

t 0

s id 0

d 0

n i

m 6

o u

c H

e s

e

(

v 0

e i

t 0

a 0

m l

i e

0 T

R 4

0 0

002 Y

p

,9 0

8 6

4 2

0 1

0 0

i Heat Transfer Rates i

1 4E+14

---Condensation heat transfer

Total heat transfer 3E+14 Decay power 30

$ ir '

, tw E

En 2E+14 jV 0

N 1 E+14

\\

O 0

20000 40000 60000 80000 100000 Time (seconds)

j ti

itl !

s 00 4

6 8

0 02 9

7 0

. 00 2

7 0

0 m

. 8 4

h 6

t_

0 g

0 t

. 6 n

7 i

5 s

e 0

0 s

)

s s

. 4 0 d f

a i

5 n

d_

M o

0 c

g d

0 e

. 2 e

t 3

s n

i v

4

(

o e

m 0

0 m

e

. 0 i

6 T d

R 3

e e

s_

0 s

0 a

. 8 g

8 C

2 t

f,

. 6 n

i e

0 s

0 a

B 1

2 00

. 44 1

00

. 2 7

0 0

4 2

0 8

6 4

2 1

1 1

cv n

a 8

4 l

1 f

8 8

m mm s

eu e

c E

o o

8 e

s R

e E

E

--H OH e

.m m0 e

me m

8 i

8 8

e e

O o

O O

O r

O v-r (6) 4

Base Case integrated Leakage 25 20 S

v G

CDf 15 -

G GJ V

$ 10 -

En G

~C 5-0 0

7200 14400 21600 28800 36000 43200 50400 57600 64800 72000 79200 86400 Time (seconds)

f oo oo o

v--

t oo

-oom e

E o

a

-o

-e o

m e

uC cc i

o oO o

1 E

i m

l

-.J j

e e

o E

u) o m

-o V

O oe e

mm cn a

oo

-ooN

)

JQ

~

/

o 5

S N

o o

o (J4/L) EP4WB 1

t, L

I I

i EI S ?r $.O a

4 8

2 6

3 2

1 1

0 0

O 00 0

63 00 e

42 t

3 a

R 0

e 0

g

. 88 a

2 kae 00 L

. 25 d

2 n

a 0

e

. 6 s

0

)

g 1

a 2 d k

n a

o 0

c e

0 L

. 0 e

8 s

d 1

(

e e

ta 0

m r

0 w

i g

. 4 T 4

e 1

tn i

0

'e

. 80 s

0 a

1 C

e 0

s 0

a

. 2 7

B 0

. 063 0

5 0

5 O

2 2

1 1

3v $fm0 egmO$E o

~

k NRC/ Westinghouse

/

Discussion item 2 Sensitivity Analyses j

Sensitivity analyses are necessary to assure that assumptions j

made are reasonable and the results are robust j

Source term parameter sensitivity analyses j

- aerosol size distribution

- inert to fission product ratio f

- particle density

- shape factor AP600 design specific input sensitivity analyses

- sedimentation area

- sequence type

- thermal-hydraulics i

i i

POLESTAR APPLIED TECHNOLOGY, INC.

W11/9718 i

l

Table of Sensitivity Analysis inputs and Results Total Sed Mass Diff Mass Thm Mass i

Sensitivity Parameter Leaked Removed Removed Removed l

Case Change Mass (g)1 (kg)

(kg)

Base Case 2 N/A 21.98 92.8 120 124 i

Aerosol Parameters Hi part dens 11.9 g/cm3 18.85 116 104 116 Lo part dens 3.25 g/cm3 23.2 85.2 126 125 Hishape 11/2.2 22.1 80.8 120 135 factor lo shape 3.25/1.5 24.2 75 131 131 factor Small part rg=0.075p 22.8 69.6 124 142 size sigma =1.4 Lo inert 3 f.plinert=1:1 11.6 38.1 62.9 67.2 r

i Design Parameters Decr sed area 3000 m2 22.7 86 124 127 incr ht xfer

+20%

20.4 84.9 116 135 Decr ht xfer

-20%

24.2 104 123 109

. Lo stm rate

-20%

22.5 98.4 116 122 Lo thm

-25%

24.1 105 130 100 Lo thm

-50%

26.6 121 143 73 Acc class 3BL T/H for 3BL 25.0 123 74.7 139 1This is the 24 hr calculated leaked mass, but is effectively the total leaked mass since leaked mass beyond about 10 hr is negligible.

2The total releaed mass is 336.3 kg for all cases except for Lo inerts where total released mass is 168.1 kg.

3The ratio of leaked mass to total released mass is increased by about 5% over this ratio for the base case.

3

00 000 1

y y

e it it s

c s

a e

n n

e s

e e

le 0

a d

d r

~,

0 t

)

C t

r

. 0 t

r 1

r e

e a

a n

0 s

s p

p i a

i o

o 8

re B

H L

L t

Z e

m d.

a r

_ * =

a 0

P 0

m

. 0

)

0 s

r

~

6 d

e n

T o

e c

c u

e r

s

(

o S

e 0

m

. 0 T

(

0 i

s i

s 0

y 4

l a

n A

y t

iv i

0 t

0 is

\\

. 0 n

e 0

S 2

'l 1

f y

0 1

8 6

4 2

0 0"

0 0

0 muf;v g"UOEoJ_.

c

i 000 0

0 1

r r

o o e t

tc c z i

a a s e F F 0

t s

e e r

a p p a 0

p

)

C a a l

. 0 2

e h h la 0

s S S o m s

a 8

i r

B H L S e

t e

m a

r a

P 0

0 m

. 0

)

r 0

s 6

d e

T n

o e

c e

c ru s

(

o e

S 0

m

(

0 i

s i

. 0 T

s 0

y 4

la n

A y

t iv i

0 t

is 0

n

. 0 e

0 S

2 l

g y

0 6

4, 2

0 1

0 o

O 5 go.EmI...

l t

0 0

0 1

y itc o

le v

0 c

0 it

. 0 e

r 0

o

)

h 8

1 po s

m r

r T

e e

T H

h t

e H

T e

s e

a e

s d

m C

s a

e c

a e

e r

u

~-

0 r

s r

c d

~-

0 a

c e

e a

B n

D R

. 0

)

P I

0 s

~. -., -

6 d

n n

g o

is c

e e

D c_

s

(

s e

0 m

is 0

y

. 0 T

i la 0

n 4

A y

t iv i

t x

isn 0

e 0

S

. 0 0

2 m

li3 j

u s

g

'1[

i g

0 1

8 6

4, 2

0 0

0 o

0 Crg cyo.EoJ.

c c

Sensitivity Analysis (Design Parameters 2) 1 Base Case

_ j;

' Ii !!

--- Reduced sed. area

'4 08

Accident class 3BL Lo steaming rate i \\

g e

lii

~

E 0.6 wp -'

N

~ c -_-- u

/

o

.O Eco 0.4

_.s 0.2 0

0 20000 40000 60000 80000 100000 Time (seconds)

NRC/ Westinghouse Discussion item 7 Lambda Uncertainty Distribution i

Quantitative uncertainty distributions vs. time and accompanying statistical measures will be addressed in the response to the RAI The following observations on uncertainties may be made:

(

- Total aerosol removal is relatively insensitive to reasonable variations in thermal hydraulics because the removal l

mechanisms are diverse and tend to compensate for one another

- Based on the sensitivity analyses, effects on aerosol removal, i

for realistic variations in aerosol parameters, are small l

i I

I i

i POLESTAR APPLIED TECHNOLOGY, INC.

2/11/97 24 i

l NRC/ Westinghouse l

[

Discussion item 7 f

Lambda Uncertainty Distribution (continued) l

\\

l l

- The lambda results are believed to be reasonably conservative based on the following:

l The STARNAUA calculation neglected turbulent diffusion l

(i.e., agglomeration and deposition) l A smaller than expected particle size distribution was used Hygroscopicity was neglected l

AP600 sedimentation area was underestimated l

i Heat transfer on the outside of the containment was f

underestimated Comparison of modified STARNAUA lambda calculation result (using SNL AP600 input) against SNL AP600 calculation (see subsequent slides) l POLESTAR APPLIED TECHNOLOGY, INC.

2/11/97 25

l NRC/ Westinghouse

[

Discussion item 7 Lambda Uncertainty Distribution vs. Time j

Input parameters used for modified STARNAUA calculation (i.e.,

using SNL AP600 input):

- Volume = 45,400 m3

- Sedimentation area = 1433 m2

- Reduced credit for thermophoresis f

- CONTAIN thermal-hydraulics Two additional modified STARNAUA calculations were performed:

(1) with credit for thermophoresis (using sensible heat transfer from l

CONTAIN thermal-hydraulics) and (2) with credit for thermophoresis and with the AP600 design specific containment volume and sedimentation area i

i I

POLESTAR APPLIED TECHNOLOGY, INC.

f 2/11/97 27 f

i t

STARNAUA Lambda Calculation Using SNL AP600 Input 1.2

SNL Lower Bound

--- Upper Bound

~-

+ SNL Median 1

'~s STARNAUA w/ SNLinput w/o thm.

STARNAUA w/ SNL input & thm.

STARNAUA w/ SNL input, thm. &

k AP600 cont. oeom.

r-0.6

~

oo

~

E

^

m o4 N___...... -

l 0.2 0

6480 10080 13680 17280 20880 Time (seconds)

NRC/ Westinghouse

~

[

Discussion item 8 Structured Boundary Layer Effects General description of turbulent boundary layer

- Laminar sub-layer next to wall

- Laminar sub-layer transitions to e turbulent outer layer l

- Laminar sub-layer: thin, strong viscosity effect, law of wall; high velocity gradient

- Turbulent outer layer: thick, strong eddy motion effect, law of wake (much flatter velocity gradient) r Sensible heat transfer

- Through sub-layer: thermal conduction with high temperature gradient l

- Through outerlayer: exchange of energy mainly due to eddy motion (much flatter temperature gradient) i

~

Condensation heat transfer (mass transfer of steam)

- Through sub-layer: steam diffusion with high steam concentration gradient j

- Through outer layer: turbulent mixing due to eddy motion (much flatter steam concentration gradient)

POLESTAR APPLIED TECHNOLOGY, INC.

2/11/97 28 i

i NRC/ Westinghouse

}

4 Discussion item 8 i

Structured Boundary Layer Effects (continued)

For aerosol transport through boundary layer, there are three i

processes to be considered:

- Diffusiophoresis l

In sub-layer: aerosol transport mainly due to shear force on particle from Stefan flow velocity (see attached equations)

In outer layer: aerosol transport mainly due to turbulent mixing

- Thermophoresis In sub-layer: aerosol transport mainly due to momentum force on particle from strong thermal gradient in gas In outer layer: aerosol transport mainly due to turbulent mixing

- Turbulent diffusion in sub-layer: aerosol transport mainly due to particle diffusion j

in outer layer: aerosol transport mainly due to turbulent mixing t

d i

POLESTAR APPLIED TECHNOLOGY, INC.

l 2111/97 30 l

l

i NRC/ Westinghouse Discussion Item 8 Structured Boundary Layer Effects (continued) l For all processes, laminar sub-layer determines limits on aerosol j

transport rates l

- Laminar sub-layer effect is quite limiting for turbulent diffusion i

since particle diffusion is slow

- Laminar sub-layer effect is much less limiting for diffusiophoresis and thermophoresis since, with heat transfer present, aerosol transport in sub-layer is not dependent on particle diffusion

- In any case, the effect of the laminar sub-layer is reduced by surface roughness i

i i

POLESTAR APPLIED TECHNOLOGY, INC.

j 2/11/97 31

1 NRC/ Westinghouse Discussion item 8 Structured Boundary Layer Effects (continued)

Effects of the presence of non-condensible. gas on diffusiophoresis is modeled in Stefan flow velocity f

Pav,, - Ddp, I dy = 0 p,v,, - DBp, ! By = w" p, + p, = const

^

%s W"

s v,, =

Ns 'E Y la M, Ps s

POLESTAR APPLIED TECHNOLOGY, INC.

2/11/97 32

l l

NRC/ Westinghouse f

Observations and Conclusions It is necessary to use AP600 design specific thermal-hydraulics and containment goometry in the lambda calculation; otherwise, the DBA fission product mitigation capabilities of the design are significantly underestimated It is necessary to consider time dependent lambdas (vs. lambdas averaged over longer time intervals) to properly address sliding dose window.

The phoretic lambda is dependent mainly on total containment heat transfer which is, by design in AP600, approximately equal to decay heat; the design specific phoretic lambda (sum of the diffusio and thermo lambdas) during the key time period (i.e.,1 to 5 hrs) is calculated to be in the range of 0.5 to 0.6 hr1 POLESTAR APPLIED TECHNOLOGY, INC.

2/11/97 =

I NRC/ Westinghouse Observations and Conclusions (continued)

The sedimentation lambda depends mainly on particle size (determined in part by particle concentration and thus by l

containment volume) and average fall height (i.e., volume to i

sedimentation area ratio); the design specific sedimentation lambda during the key time period is calculated to be in the range i

of 0.15 to 0.2 hr1 The total lambda during the key time period is calculated to be in i

the range of 0.6 to 0.8 hr' l

The total lambda is robust and reasonably conservative based on the rnodeling in STARNAUA, the results of the sensitivity analyses, and the comparison of the modified STARNAUA result I

against the SNL AP600 result r

POLESTAR APPLIED TECHNOLOGY, INC.

2/11/97 38 I

i

e F

Treatment of Boundary Layer in Westinghouse Codes i

o The bounua;y layer is not specifically modeled in either WGOTHIC or MAAP4 Boundary layer correlations for heat and mass transfer in the codes implicitly include the effects of laminar sublayer and buildup of noncondensibles since those effects exist in the i

test database from which the correlations are derived.

The test database covers the range of conditions expected in the AP600 post-LOCA environment At high condensation rates associated with the-environment post-LOCA there is a velocity component normal to the wall the boundary layer correlations used in WGOTHIC and MAAP4 include a log mean noncondensible pressure term to account for the effect of the buildup of the noncondensibles on steam condensation n

m E

l e

we w. m..

,.a, _,.u _,,_

, _;,, _ ;.,,,,_7,

,7 - -~

4 4

s 1

i

+

e Q

e YJ 4

C A.

~

+' k S

-f N '

y L

i 3+4 J

h v

r.

c 2

i+ne7Y 3.g y*

y a

w it j esy S

L L

es 4

e e

gw

}

g I

E

,t

,n b

4,!

q.s-e p

q s

a r

2 E

-# n (,E 5+!

k he 4

'j3~1 J 2 l4 g

s S

3 d

0

e,0 p3%

6 4

4 d

jO 4 0 I d so v

v v

qIt{

.[

[

f

[

.q

%3 V

\\-

' [

g A

h3

=; 3.,e 0N

\\

}

x U)

=co

F t.D W 'V( l a s A D FM Wt;l p tvi '+oo c.w c.no s se as,

.J s -e ass sw w+ w.s nm*

.w-e c

{

J ta=

oL O_.

l tu A

l tl d

5 l

J n

g D

L l<

kW W

t 1

)

h, t o p

o s

4 Q 'p t

nn o

i 0

_J )

L o

i g

I x;

,o ev 4

j\\n 3

L i

3 4

1 i

c+.

+*-

5 9 x

M 4

1 d

1. vA i

E

e Wi J

---D.

E S n

_14

.tt

.f, -

a W

N 93 i r aw u.a r

g".

6(

R_ N r,

j

- 1 a

.y

\\

3 i

7

/

\\

/

.h

~

/

i

/

1 m

4 j

1 3

4

i ISSUES THAT WERE RESOLVED DURING THE MEETING A)

Items from NRC Letter from T.J. Kenyon to N.J. Liparulo dated January 10, 1997, " Discussion Items on Source Term Related Issues for the AP600" January 10, 1997.

t 1)

Items numbers 1, 2, 3, 5, and 8 under Aerosol Behavior and Removal were satisfactorily resolved during the meeting by the presenta-tion given by Westinghouse's contractor.

8)

Issues raised by Attachment 2 during the staff's presentation 1)

Issue 2 and 3 were resolved by Westinghouse's contractor during the meeting.

l C)

Three issues raised in the conclusion of Attachment 3 1)

The concern about boundary layer depletion was resolved during Westinghouse's contractor presentation.

D).

The NRC staff provided a copy of the following document, that is avail-l able to the public, to Westinghouse during the meeting:

i J. Green and K. Almenas, " Condensation Heat Transfer in the.

Presance of Noncondensible Gases as Applied to Containment Analy-l-

sis," University of Maryland, submitted to the NRC June-1, 1993.

j' E)

Dr. Powers at Polestar's request answered several questions concerning his report titled " Monte Carlo Uncertainty Analysis of Aerosol Behavior in the AF600 Reactor Containment". These questions were in addition to

{

the' questions that were asked in the December 3, 1996 letter from Westinghouse.

Polestar believed that the questions may effect the 4

conclusions reached in the above report. Dr. Powers responded to the questions and it is the staff's belief that the answers do not effect the 4

conclusion in the report. Dr. Powers provided explanations for the following:

1) how the aerosol fission product removal coefficient was calculated prior to 6480 seconds, 2) the model used to obtain the shape factor used in the thermophoresis calculations, 3) the thermohydraulic code that was used in the report, and 4) how the thermal conductivity for gas mixtures was obtained.

i

o

=

1 NRC/ WESTINGHOUSE ACTION ITEMS NRC i

A)

Review containment mixing model proposed by Westinghouse in 4

l February 7, 1997 letter.

i B)

Questions were addressed concerning Westinghouse's February 7, l

1997, submittal on mixing in the containment.

These questions were raised during a telecon that was held on February 12, 1997.

1)

The NRC will evaluate Westinghouse's explanation for the difference between the heat transfer and heat generation rates.

(Westinghouse explained that the difference between l

the two rates was due to raising the water in the in-con-tainment refueling water storage tank to saturation).

4 i

2)

The Westinghouse evaluation assumed that the hydrogen igniters operated. The NRC will evaluate the ramifications 1

of igniter operation.

4 Westinghouse A)

Items from NRC Letter from T.J. Kenyon to N.J. Liparulo dated January 10,1997, " Discussion Items on Source Term Related Issues for the AP600" January 10, 1997.

1)

In response to item 4 from this letter Westinghouse will respond to Dr. Powers concern raised in Attachment 4.

i 2)

In response to item 6 before the final run of STARNAUA is performed Westinghouse will inform the staff of the input parameters that will be used in the code.

j 3)

In response to item 7 Westinghouse will address the uncer-l tainty distribution for the aerosol removal rates. (See j ).

I B)

Issues raised by Attachment 2 during the staff's presentation 1)

In response to issue 1, Westinghouse will provide confirma-tion of consistency between the models used for calculation of aerosol removal coefficients and for demonstrating mixing

'in the post-accident containment atmosphere.

2)

In response to issues 4, and 6 Westinghouse will reassess the aerosol particle shape factors.

s.

.g 4

f 3)

In response to issue 5 Westinghouse will provide a justifi-cation for the sedimentation area of 3500 square meters and why resuspension of deposited aerosols is not a concern.

4)

In response to issue 7 Westinghouse will provide documenta-tion for the value'used for the non-radioactive aerosol mass.

'C)

Three issues raised in the conclusion of Attachment 3

1) -

Westinghouse will document the reason for not including hydrogen in the calculations.

i 2)

The action items for the well mixed containment atmosphere l

are covered under items A.1, 8.1 and D.

f D)

Questions were addressed concerning Westinghouse's February 7, 1997 submittal on mixing in the containment. These questions were raised durina a telecon that was held on February 12, 1997.

l 1)

There was a discussion concerning the entrainment rate used by Westinghouse. A rough calculation by the staff for the entrainment rate (see attachment 4) did not correspond with 1

Westinghouse's value, (This is the same action as A.1)

I 2)

Westinghouse will evaluate the information notice concerning decay heat models for applicability to the decay heat model used in the February 7, 1997, submittal.

3)-

In it's February 7, 1997, letter Westinghouse assumed a containment value of 40,360 cubic meters.

In attachment 5

]

Polestar used a value of 45,797 cubic meters for the con-tainment volume in its calculations. Westinghouse will provide an explanation for the two different values.

E)

Westinghouse will evaluate the presentation given by Dr. Powers (Attachment 3) to see if it has any additional concerns.

1 I

l

. - -

ML20136H692

Contents

Text

SUBJECT:

SUMMARY

~ c -_-- u

Navigation menu