ML19331B894
| ML19331B894 | |
| Person / Time | |
|---|---|
| Site: | Allens Creek File:Houston Lighting and Power Company icon.png |
| Issue date: | 08/07/1980 |
| From: | Brooks W Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML19331B836 | List: |
| References | |
| ISSUANCES-CP, NUDOCS 8008130495 | |
| Download: ML19331B894 (29) | |
Text
. _ _ _.
O UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION BEFORE THE ATOMIC SAFETY AND LICENSING BOARD In the Matter of HOUSTON LIGHTING & POWER COMPANY
)
Docket No. 50-466 (Allens Creek Nuclear Generating l
Station, Unit 1.?
)
AFFIDAVIT OF WALTER L. BROOKS CONCERNING DOHERTY CONTENTION 46 My name is Walter L. Brooks.
I am currently employed by the Nuclear Regu-latory Comission as a Nuclear Engineer in the Core Performance Branch of the Division of Systems Integration. A statement of my professional quali-fications is attached.
The purpose of this affidavit is to address Doherty Contention 46 which reads as follows:
This Intervenor contends control rods capable of causing a five secor.d period on being withdrawn one notch, if uncoupled from their drives and stuck in the core could, by falling several notches moments later cause a significantly shorter period leading to fuel damage. The core conditions necessary for fuel damaging
(
short periods such as these are three:
l 1.
when there is high xenon concentration in the reactor core (high xenon concentration magnifies the worth of certain central control rods until burned off),
2.
moderatortemperaturesarehigh(200*F-480*F),and 3.
the percentage of voids in the coolant 'was greatly reduced.
,8008130%g A.
INTRODUCTION The Staff agrees, as Intervenor contends, that if there are control rods with rer.ctivity worth capable of causing a five-second period in the ACNGS reactor when withdrawn one notch, they would be capable of causing a signifi-cantly shorter period if they became uncoupled from the drive mechanism, stuck in place and then, subsequently, fell several notches. While this rod drop scenario could result in fuel damage, the postulated fuel damage does not exceed the limiting fuel damage specified for the design basis control rod drop accident.
For the reasons set forth below, the Staff concludes that the design criteria and limits proposed by the Applicant and accepted by the Staff, provide generous margins to fuel enthalpy limits relative to any uncertainties in choice of the design basis control rod worth and, consequently, envelope the postulated fuel damage resulting from the above described rod drop accident.
B.
DESIGN BASIS CONTROL R0D DROP ACCIDENT The Staff's reviews of the control rod drop accident is described in Sec-tion 15.h2 of Supplement No. 2 to the Safety Evaluation Report, NUREG ' 515, March 1979.
The review relies, in part, on the Staff's conclusions in its prior approval of General Electric Topical Report NED0-10527 " Rod Drop Accident Analysis for Large Boiling Water Reactors."
On the basis of the analyses in NED0-10527, the Staff concluded that to produce a resultant peak fuel enthalpy greater than 280 calories per gram,1/
1/
The peak fuel enthalpy limit of 280 calories /gm is a criterion applied to BWR rod drop accidents to assure that gross fuel failure and rapid dispersal of fuel into the moderator do not occur.
l l
the value for inserted reactivity worth would have to be greater than 0.013 6k/k. The rod pattern control system for Allens Creek is to be designed to limit the maximum potential rod worth to less than 0.01 ok/k. Therefore, based on the generic analysis and the preliminary design criteria at ACNGS, the Staff concluded that the reactor will be protected against the possi-bility that a rod drop accident will result in a peak fuel enthalpy greater than 280 calories per gram (SER, Supplement 2, Section 15.3.2 (NUREG-0515)).
The Staff accepted the results of the generic analysis set forth in NED0-10527 because of methodology, the reasonableness of the parameters chosen for analy-sis, and the adequacy of preliminary margins to the fuel enthalpy limit.
As an example of this margin, the maximum dropped rod worth identified in NED0-21231, " Banked Position Withdrawal Sequence," was 0.0083Ak/k, whereas to produce the peak fuel enthalpy greater than 280 calories per gram requires, as indicated above, an inserted reactivity worth of greater than 0.013 Ak/k.
Thus, for the control rod drop accident postulated by the Intervenor, the maximum rod worth identified in NED0-21231 (0.0083Ak/k) must increase by approximately 60% to exceed the 0.0136 k/k value needed to reach the peak fuel enthalpy limit, and approximately 20% to exceed the rod pattern control system design limit of 0.0106k/k.
Experience and data suggests that such large increases are not associated with high-worth per notch rods because' total worth per rod is inherently a small fraction of the worth that would be postulated if all notches were of the same high worth.
For example, rod drops of two to three feet (eight to twelve notches) yield incremental rod L-worths comparable to rod worths for rod drops of 12 feet (48 notches).
See ACNGS PSAR, Fig. 15.1.38-1.
In addition, several similar curves are shown in NED0-21231 which indicate that for a wide variety of core conditions and drop distances, the rod worths for each condition ranged from a low of 0.005 A k/k to a high of 0.0083 Ak/k.
Therefore, the Staff concludes that other accident scenarios and core conditions not analyzed in NED0-10527 should not result in rod worth increases that exceed the rod pattern control system design limit of 0.010 Ak/k.
C.
EFFECT OF HIGH XENON CONCENTRATION However, the Intervenor contends that a control rod drop accident may cause fuel damage when there is a high xenon concentration in the core because the xenon will magnify the worth of certain central control rods until it is burned off.
Af ter a reactor shutdown, the amount of xenon it. the core increases until it reaches a peak in about eight or nine hours after which it starts to decrease, returning to its full power value at about 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and finally decaying away to essentially zero in a few days. At peak xenon, the distribution of xenon will be approximately like the power distribution was at full power.
The radial distribution will be essentially flat (and high) through the central portions of the reactor and will be low at the radial periphery.
L Thus at peak renon, the total worth of the peripheral rods would be increased and that of central rods decreased relative to their worths in the "no-xenon" condition.
Since the peripheral rods have low total vorths, this enhancement l
{-
by xenon is relatively insignificant and certainly will not exceed the rod worth required to reach the fuel enthalpy limit.
The axial variation of xenon has the same type of configuration. That is, at peak xenon the amount of xenon is high and relatively flat at mid-elevations but is low at the top and bottom of the core. Thus, the incre-mental worths of the rods (worth per inch of travel) would be greater at the
[
ends of the travel and less in the mid-range than in the non-xenon case.
This means that the worth of the first notch or two of a relatively high worth rod will be enhanced and might lead to a "5-second period," but the total worth of that rod wauld be less than the non-xenon value. Since the total worth is what is important in the rod drop accident, it is concluded that the high notch worth due to xenon does not impact on the consequences of the design basis accident.
It also should be pointed out that even though the effect of xenon enhance-ment has not been calculated, the effect of rod total worth enhancement by flux distortion has been analyzed in NED0-21231 " Banked Position Withdrawal Sequence." Tha flux distribution distortion was created by inserting rods on the opposite s'oe of the reactor from the most reactive rod and its worth 4
increased by about fif ty percent (from 0.0083 to 0.012dk/k).
The conse-quences of the rod drop accident rose from 135 cals/gm to 232 cals/gm if the conservative "all-rods out" scram curve is used.
If the realistic scram curve is used the consequences are less than 100 and less than 180 cals/gm l
respectively.
Thus, the consequences of the conservative flux distortion condition still do not exceed the peak fuel enthalpy limit of 280 cals/gm.
D.
EFFECT OF MODERATOR TEMPERATURES BETWEEN 200*F AND 480'F The Intervenor has also contended that the effects on the rod drop accident have not been analyzed during heatup of the reactor where moderator tempera-tures are near saturated conditions (200* to 480*F).
Calculations have, t
j however, been performed by our consultant, Brookhaven National Laboratories,M which show that, in this range of temperatures where the moderator is near saturation conditions, the effect of moderator heating on the consequences of the accident is significant.
Inclusion of direct moderator heating 4
(neutron themalization and gamma heating) reduces the consequences by about 35 percent for a rod worth of 0.0126k/k and inclusion of both direct and delayed moderator heating reduces the consequences by about 75 percent relative to the c61culations previously accepted by the Staff in NED0-10527.
Thus, the design basis accident calculation, where the fuel temperature is 480*F, predicts much more serious consequences in this thermal hydraulic range than are anticipated at moderator temperatures in the range of 200*-
480 F.
Accordingly, the Staff concludes that the consequences of the rod 1
drop accident in this temperature range are bounded by the design basis accident.
l l
2f Themal-Hydraulic Effects on Center Rod Drop Accidents in a Boiling l
Water Reactor, BNL-NUREG-27544 (to be published),
t..
I, L.
_ E.
EFFECT OF REDUCED VOIDS Finally, the Intervenor contends that a core condition where the percentage of voids in the coolant was greatly reduced could cause a significant shorter reactivity worth period leading to fuel damage. Again, the Staff is of the opinion that this scenario is enveloped by the design basis dropped rod a:cident because that accident assumed a core condition of no voids.
This condition represents a " worst case" condition because the presence of voids in the core reduces the effect of a particu' r rod motion (i.e., reduces the rod worth) and makes the Doppler coefficient more negative.
Both these effects reduce the consequences of the event when compared to the no void Case.
F.
SUMMARY
In summary, there are a vast number of conditions from which a control rod drop accident could begin. Many have been analyzed in a conservative manner i
and the results indicate that wide margins to fuel enthalpy limits exist.
t While it is conceivable that " worse" initial conditions could occur, major reductions in margins are unlikely.
The Staff believes, therefore, that there are no significant issues posed by this contention for the following reasons:
1.
The fuel enthalpy limit is 280 calories per gram.
I 2.
A total rod worth greater than 0.013 Ak/k must result from a control rod drop to yield a fuel enthalpy of 280 calories per gram.
3.
The rod pattern control system will be designed te limit the maximum potential dropped rod worth to less than 0.014 k/k.
4.
Total worths of control rods dropped order under other situations that exceed 0.010 Ak/k, i.e., an increase of 20% of the maximum rod worth identified in NEDO-21231, is not likely.
}
5.
If 0.0106k/k is exceeded, the Applicant is still committed to design the rod pattern control system to limit the maximum worth to 0.01 A k/k.
6.
The presence of enhanced notch worths due to xenon in the core does not imply increased consequences for the rod drop accident. On the contrary, the conditions which produce enhanced notch worth tend to cause the total worth of the high worth rods to be decreased.
7.
Drastic patterns such as insertion of rods on the opposite side of the f
core from the most reactive rod cause an increase in worth of the maximum rod from 0.0083 to only 0.012tkk/k.
8.
The effect of the enhancement of the total rod worth by flux distribu-tion distortions has been treated in the analysis of the event and the consequences shown to be acceptable.
9.
The postulated thermal hydraulic conditions in the core (200"-480*F) actually reduce the consequences of the design basis rod drop accident through enhanced moderator feedback.
i
.g.
- 10. A core condition of no voids represents the " worst case" condition because the presence of voids reduces the effect of a particular rod motion (reduces the rod worth) and makes the Doppler coefficient more negative.
I prepared the foregoing affidavit and swear that it is true and correct to the best of my knowledge, infomation and belief.
} WCD %-
Walter L. Brooks Subscribed and sworn to before me this 7th day of August 1980.
LW LUL Y
'h NotarfPublic
/
My Commission expires:
July 1, 1982 f.f '
)
w
)
i f
9 yr 51ATrl:E';1 OP M.0TESS10NAL QUALIP1 CAT 10:n OP
/
l k' alter L. Erooks
~.
Y Present Enployment - I joined the Nuclear Regulatory Commission (then the
/
Atomic Energy Commission) in September of 1974.
I am a acmber of the Core Performance Branch of the Division of Systems Safety with the title of Nuclear Engineer.
In my position, I have prieary review responsibility for core physics aspects of licensing submittels and, upon request from the Auxiliary Systems Branch, the criticality aspect of fuel storage facilitier.
Education - B.A. in Mathematics, Lincoln Memorial University, 1943 M.S. in Physics, New York University, 1950 Ph.D. in Physics, New York University, 1953 Previous Employment - Gulf-United Nuclear Corporation and its predecessor
[
companies, United Nuclear Corporation, Nucicar Development Corporation of America, and Nuclear Developn.ent Associates. My duties, during my euploy-dbnt from 1953 to 1974, included the following:
- Performance and evaluation of critical experiments for D 0 moderated latices 2
Performance and evaluation of light water moderated lattice critical experiments
- Performance and evaluation of fast reactor critical experimet.cs
- Development of calculation methods for D 0 moderated 2
reactors Verification and mofification of a nodal calculation technique for light water reactors.
l Publications l
Numerous reports on the results of critical experiments and g
methods development.
e 0
- e
.s-
~
= -
DOHERTY CONTENTION 46 l
1 A.
Yes.
C.
And those here ex tr ac ted from the 2
!?u c l e a r refety Tabul a tion s?
l A.
Yes.
~
5 c.
And r.y question is, sirrly stated, so f
- s. h a t ?
9 hat doer that have to ?o with tbc 7
A.
" hose Ilqures we r e put in to establish 9
the unreliability of the Ariw system.
l P
O.
All right.
1 r, p.
The
- 1. r.t r. s y s t e r-s ware +: e n t i e n c r' to 31 indicate how t !. 0 FCIF f ailur et cr b yp a t:s e s n iij h t 12 be'rore serious.
32 O.
All r ii; h t.
tkay.
Le t 's go to your.
14 contention n u.~ b e r /C which I cell short reactor, 15 period.
16 Do you have anything tha t needs to be I
17 duplicated from that last one?
r-1*
A.
One item.
19 0
I want to ask you a few preliminary l
20 questions on the actual physical events.
Would 21 you describe fo r me how a rod can be uncoupled 22 fron its drive?
22 A.
Well, there have been several reported 24 ways.
I will attenpt to find them.
25 Say again.
I'm sorry.
I don't have the INTERNATIC?lAL COUR7 REFCETERC, INC.
l
!!cusTcN, texas (712) 452-Sc11 L
a
.6-
~
o I
question in n i r. c.
2 c.
can you describe for me bow a rod can be 3
uncoupled fron its drive?
4 A.
So we need to find the coupling.
- Uc11,
~
5 the ACHS r e t.o r t ed that thera sere several events 6
of this t y :. e.
7 C.
Tha t have cetually occurred.
Feveral 8
rod uncouplings in rods of the s c.r. e variety as 9
being installed on the A c t; C.S ?
10.
A.
To ny knowledge.
11 C.
You 6cn't now have a f anilia r i ty with 12 the nechanisms for those on couplings of your own 12 knowledge, do you?
It A.
There is a type of rod, and I nentioned 15 it in one of the interrogatories, I think the 16 Staff which has I think it's called an un-l n
17 coupling rod which has caused uncoupling itself 18 while the thing was in operation.
It wa s n ' t 1.
19 ceant to I?*
20 C.
You don't know wh e the r or not that's 21 planned for insta*1ation at Allens creek?
22 A.
No, I don't.
23 C.
Le t's assume that it's in those 22 notorials you have in front of you, and we can 25 find it on on our own search later.
I.s T c n v /. T : c :ci. I.
Cttus a f. r 0 P T t 9 r, Inc.
!! O U S T C.9, TEXAU (713) 452-5P11 t
1 A.
holl, I don't i. :. c. t i.a t I can find it, 2
but go ahead.
3 C.
Can you describe for ce how the rod can 4
become stuck in the core once it's uncoupled? -
5 A.
There is very little tolerance or extra 6
srace in between the channels.
7 C.
All right.
0 A.
Fo that v e r y
.e.e a g e r amounts of 9
vistortion at all can hold the rod there.
I r, C.
Kha t's going to cause the distortion?
13 A.
A nucher of f acto rs alparently have.
17 C.
There have been instances of t
1.'
A.
Cf sticking, yes.
1<
C.
,T 1 1 right.
4 15 A.
Yes, there have.
16 C.
to you have those references at hand, or 17 are they lost in those papers as well?
18 A.
They are lost in these papers as well, 19 unfortunately.
70 C.
All right.
Le t 's press on.
Assunino it 21 comes uncoupled and stuck in the core, how can it 22 fall core than one notch?
23 A.
If it's not noted that it's there, it Of can fall further.
Mr.
Ep l e r has cited at Cresden 25 I where a rod becane sepa ra ted as a result of INTER.NATICNIL CCCRT BrPCRTCRE, INC.
hCUSTCN, TEXAS (713) 952-5911
6 3
structural failure.
2 0.
ftuck in the core and fell s2veral 2
notches?
4 A.
Ye s.
i f
C.
What is the !.c r p o s e of notches?
r A.
To prevent insertion of reactivity too 7
r a t. i d l y, or to !; r e v e n t a reactivity increase.
C C.
To this a c t u cil l y provides a :=chanism i
e 9
fo r latching the rods so that it een only ove in 10, discreto i n c r ira e n t s ?
II 3.
':o.
1; C.
They don't contrit.ute to the lotching of 22 the r od s?
I It A.
They latch the drive, not t re e roc.
a 5
15 O.
So the drive in then connected to the
- r IC
. :. o r 17 A.
If the drive becones disconnected fron 18 the rod, it wouldn't do that.
19 C.
Fo if the rod becane cisconnected I'm 20 sorry.
If the rod became disconnected fron the 21 rod then and stuck in the core and then sonehow 22
' released, what would arise?
Its descent?
2 A.
The drive s
24 c.
bould inpact u l t i r. a t e l y should arrest it.
t.l s o 25 A.
I I ". r R." A T I C F A L COUP 7 PCPCRTfBC, I *. C.
i
.i!Ct!S 7 0'l, TTXAC (712) 652-Sall
~
1 the velocity liniter.
7 C.
So it would cone in contact with t." e 2
drive cgain.
So you're surnising that or your 4
hy po ti.c t i c a l envit.1ons the fact that the control 5
red becomes uncoupled and that the drive is 6
retracted several notches, and then the control 7
rod falls that distonec?
P A.
ses.
S 0.
ckay.
I'o w is this scenario any 10, different from the design basis rod dror accident?
II A.
The conditions of the core are different 12 in r eg a rd to hot stort up conditions and in 10 r e.3 a r d to
!. i g h xenon condition: which occur r i t: h t 1/
after a control rod has been noved down culte
~
5 15 frequently or reinserted and coved down.
1G O.
what is tnis difference in conditjon 17 which alters the analysis arrlied to the 1*
A.
If it occurs at het start up, the void If fraction is very low because the coolinc is quite t'
2r hot.
21 0
The void fraction is Icv r. caning there s
72 is a nunber of voids, a g rea ter number of voids 22
.present in the core?
24 A.
I'c.
S'e a n i ng there are less.
75 C.
If the sater is hot, hy is there less I N S E.L.N A 1 I C N A L C O L'l: 7 EErCW.ihr,
- 1. ' C.
!! C L S TC ::, TEXAS (712) 452-5911
l i
voids?
2 A.
Kell, the water hcs hecn hotter cn? it 2
has cooled scoe but not euch, and in that eccling
/.
the volds have c.o v e d out of the core.
5 C.
'<' h a t are tbc initial conditions for the C
for the desion hosis rod drop?
7 A.
Un fo r t una t ely I don't know what they are 1
5 r iv is t offhand.
This does descri:.c the CL/ to cn I think 9
cxtent.
I think the c e l.
talks about F
10, the DBA sets a requirerent of a full 4." notches, 11 I believe.
12 C.
That would be even note 12
.t.
Even more.
F. u t I don't knew that it It sets these conditions in the xenon.
9 I
15 C.
All right.
IF A.
Cases in the fuel rods.
i 17 c.
So for right now, you believe that this i
13 is a more consecuential accident because of 19 noderator temperature and the fresence of xenon; 2C is that correct?
21 A.
Yes.
I think tnere can be local core 22 dacage.
22 C.
Civen the presence of xenon and certain 24 coderator tenperatures that are not accounted for
'25 in the dropped rod?
I8 INTER.NATICNAL CCURT BEPCRTEEG, I.N C.
I:CUSTON, T C.M A S (712) 6E2-So11 v ',.,
A
I 1
1.
That's r1 9 St.
f 2
C.
Po w does xsnon affect rod notch worth?
2 p.
i.e l l t.
C.
Or incrinental rod worth, or total rod 5
sorth, or any rod worth
.v.e a s u r e m e n t you choose?
6 A.
Xenon has a hig h residence absorption.
7
- 1. hen it's present, it makes fissionino nere e
efficient then after when it's inverted, and I'n 9
not certain I have this correct.
It r e l. l a c e s 10, let's see.
t.1 1 right.
Il Xenon is a deg r eda tion Iroduct of Iodine 12 135.
Iod ine is gas in the feel rods, and it has 12 a certain residence c b s o r !. t i o n of fis.sian neutrcn.
1/
As it c h a :.s os froa Iodine 125 to xenon I
15 135, that property in the fuel rod changes.
That 16 is, it changes the amount of fissioning that will s
17 go in that fuel rod.
18 Now, does that seen to answer your 19 cuestion or no t?
20 0
Control rod is a ( po i so n), is it not?
21 A.
All right.
1 22 0.
So that as it's retracted from the core
)
23 by falling in this case, it inserts positive 1
24 reactivity by the absence of the poison?
25 A.
Yes.
1.v T t. a 9 /a 16 :s A L L L L i: 7 n s. H; n i e n d, J r. L.
hCLSTCN, TEXAS
('12) 652-5911 y_ +_
1 C.
Ckay.
I'n acking how does the x o r.o n 2
conditions affect ti.e a.n o u n t of reactivity 3
incerted by renoving the poison control blade 4
from the core over a certain s;-a c e ?
5 A.
It increases it.
A C.
Inc r ea so n tne enount of reactivity 7
inserted by w i t hd r a s. i ng the roc?
C A.
Yes.
C O.
- l. o L. ?
1 r; A.
because t! e residence absorption of 11 x e rt o n 125 is greater than Iodine 125, except that 12 core neutrons are absorbed in the fuel redc.
1 C.
'< h a t ' s that got to do with the presence 14 or absence of the control rods?
15 A.
It has to do not really with the you 16 can ta ke one group of core conditions and i
\\
{
17 calc ula te the affects of a d rop o f a notch or L
13 wh a teve r and get one set of res ul t s.
Yo u can
)
l 19 take another and get a different set.
?C Now, grr.nted, the fuel rod or the 21 control rod. drop is a drop.
There will be a 22 difference in results if it happens that there's 23 a great deal of xenon in the fuel rod space 24 between the pellets and the 25 c.
That s ta te s a conclusion.
I don't I N T E R.N A T I C ' A L CCURT F F F C R '.'f H S, I t. C.
j iiOUSTON, TEyAS (713) 652-5911 u
\\
.understtnd the causal ri e c t a n i s n.
bhy does the
~
}.resence of xenon is xenon a I.o i s e n, inci-3 dentally?
t.
A.
No.
Not in the sense 5
C.
Xenon does not absorb 6
A.
No.
It doesn't keep then away from the 7
fuel rod.
6 C.
If xenon is not a polson, how can It 9
affect the fission r a te et all?
s.
10, A.
bell, it acts i t's like a r o d.? r a t o r 11 in the sense that it increases the percentage of 17 neutrons that causes fissioning at that place.
12 C.
Xenon acts too slow down 1*
A.
Ca t, t u r e 15 C.
Excuse me?
Ic A.
So r r y.
i 17 c.
A noderator will slow down the neutron l
15 and attempt to thermalize it?
19 A.
I've never heard it that way.
20 C.
This is a thernal neutron core; correct?
21 A.
Yes.
22 C.
A mod e ra to r will slow down neutrons?
23 A.
Yes.
24 C.
Xenon acts in that capacity like water, 25 it slows d
.i the neutrons?
19 i t c.s t. i l t U.i L.
L t. L si i F: 1 1. it '4 :..~ 1', i t. C.
j -
1:C U S T O N, TEXAS (712) A52-Scl1
~ _.
1 A.
No.
- 71. e tern used is r e r. i n i c capter2.
2 It'c a different process.
2 c.
tiha t does this resinic capture do which 4
affects the rod notch worth?
5 t.
It increases the rod notch worth if it 6
is present.
7 C.
I:o w?
n A.
hy capturing nore neutrons and r !
9 i n c r e a s i rig the fission as a result E
10, O.
1:a i t a ninute.
11 A.
All right.
12 C.
You're telling
.m e it wasn't a 1:o i s o n, so 12 I don't know how it can capture neutrons.
If i t j
14 does, then t !.e r e ' s less neutrons --
i lj 15 A.
The process appears to be one sinilar to l., -
16 noderating.
I don't want to say it's the sane.
17 C.
Foderating is the antithesis of capture.
t.
- 1 f,i 18 It does not capture neutrons.
It reflects then 19 and slows then down.
20 A.
Fa ther than hanging up on trying to cet 21 the exact label for process 3.
22 Q.
I'm not interested in labels.
I'm 2b interested 24 A.
It's impossible for me to explain it q-25 without using some kind of analagy for a process.
IN1ERNATIONAL COURT REFORTERS, INC.
HCUSTON, TEXAS (713) 652-5911 g
_.N e_.
+
6
U 1
C.
Chay.
I.e t ' s select 2
A.
I think coderator is a reasonable 2
analogy.
4 0
So it's your belief that xenon slows i
1 '
5 down neutrons like water does?
6 A.
It doer sonetting to then to
.m a k e them 7
nore likely to induce fission.
O C.
cxay.
You carefully worded that not to 9
infer that you're not r?cre what it does to the 10, neutrons.
11 A.
I don't have the 1 roper term.
I'r not 17 satisfied with "carture.'
And I ' r.
not satisfied 12 with "roderated."
It O.
Put something magical her: pens in the e
15 presence of xenon which :akes fissioning
.r. o r e IF likely; r ig h t?
17 A.
The processes has been recognized fo r le over 2C years as occurring.
19 C.
I didn't say it doesn't occur.
h'e ' r e 20 h a v i ng difficult of your explanation of it.
~
A.
The word "nagical" was disturbing to no.
21 22 C.
All right.
Let's take it out of that 23 realm.
Can you describe it nore concretely?
)
2d A.
No.
That's about the best I can do.
25 You get the result from this that I've described.
I ::i E F." A T I O N A L C O L* R T DEFCRTLRS, I ?!C.
li C U S T C N, TEXAS (712) if2-5911
-v
k' 1
(.
All right.
And you believe that the 2
presence of xenon and it's affect on neutron:
I will cause a localized fissioning rate greater 4
than that allowso for in the analysis of the 5
design basis rod drop accident?
C 9
Yes.
7 C.
Le t 's go to roderator tc,perature. 'hhat e
does nodera ter t e n g. e r a t u r e c' o as an initial c
condition which causes this scenario to be worse Ir.
then rod drop?
A.
All right.
Ten r e r a tu r e alone would 12 decrease the moderation, because the water would 12 ee less dense.
14 C.
Yes?
i
\\
15 A.
If voids, however, are absent, then it's 16 possible to overcome the fact that the water is 17 at a higher tenperature such that the coderating j
IE wo uld be more substantial.
l le C.
Okay.
bell, you list under your three i
20 conditions xenon conce t ra tion, noderator 21 temperature and pe r cen tag e of voids.
You were 22 describing your last s ta ter en t the affect of 22 percentage of voids.
2#
Is noderator temperature a s e }.a r a t e 25 initial condition with its own affects, or are I.s'a t h N A T I C U A L CCUPi RLFC5"EEC, I t4 C.
I! C t'." T C N,. TEXAS (712) 652-5611
I
_1 there only two ' xenon co nce t r a t ion e r.d Icreentage 2
of voids?
3 A.
I think there are really only two.
Le t t
ne see.
Yes.
I think tha t's right.
5 c.
Is xenon condition and rcreentage of vo id s?
7 A.
Ye s.
S 0
All rigat.
I.e t ' s take r e r e e n t a ey e of 9
volds.
Is it a high r.c r e en t ag e or low percentege 14 that's the problen?
11 A.
The problen is low percentage.
17 c.
Al l right.
Lo w percentago of voids 13 neans thet there is
. ore noderator in existence 14 and you nay have.~ere neutrons and nora 15 fissioning; is that correct?
14 A.
Fore fission.
17 C.
All right.
Co that when a rod drops l
12 under these conditions, your localized fissioning
~
19 is allegedly greater than that analyzed?
2C A.
Yes.
21 Q.
Okay.
So what's the basis of these
~2 2 of your conclusions as to the affects of initial 23 conditions on the analysis anyway?
24 A.
They are costly d e r iv ed from the NURPC 25 0572 conclusions.
I N T F.H N A T I O N A I.
COURT R E P C S T.S fs S,
INC.
I ~~
1: C t' S T C N, TEXAS (713) 657-5911 s
(.-
~
t
.I C.
0572.
khat's the title of that N U r. E G 7 7
A.
Review of Licensee Events Petort, IE76 3
to 197E.
4 C.
Was that authored by the
- t. C B F 7 5
A.
Yes.
C C.
ro w, did t in e I.C E F express the identical 7
concern that you've s ta ted here that a control P
red of this descri. tion could ited to fuel d a r. a c e ?
l 9
A.
Yes.
20, C.
Fould yee find that fortion of the
.c U 31'C 21
- 'oro thay reach that c a r. e conclusion?
12 A.
Yes.
Pa g e E-A and P-3.
12.
C.
Chay.
-I s there a particular portion of 14 quotable length?
15 A.
Alnost in itc entirety quotable.
That's 16 all there is.
]7 Q.
Fa y I see that?
18 A.
Sure.
19 C.
Ckay.
Is there any other basis fo r your 20 assertions other than the NUPEC?
21 A.
No.
I've I take the ACBS as I.r e t t y 22 good, so I haven't searched around for any others.
23 There have been some INE reports of this.
24 0
The ACES expresses a concern for short 25 reactor period.
Cf what sa f o ty concern is short I N 'i l:E!:AT ICI: A L C C L'H T Fr.FCHTEES, IVC.
h0US7CN, TEXAC (713) G52-5011 L :-
v 1
- sac ur fericc?
I A.
As I understand reactor period, it ra e a n s 2
there is an occillation in conditions such as the chorter period of time, the pore concentrated the 5
event is.
r, O.
hhat event is of concern here?
7 7.
The event here is insertion by a rod 2
drop.
f C.
All right.
'culd you restate your 10 definition of short reactor period?
11 A.
Yes.
I'o trying to recall t h c. t.
12 C.
Le t ne try a n o t i.c r cuestion and cet to 12 it from e different angle.
1/
Le t 's assure that everything you say as 15 of this point is true that the conditions can 15 exist, this rod can exist and it does drop 17 several notches.
Chen what happens?
18 A.
The delayed neutron fraction is 19 accumulated to the next generation of r.e u t r o r.s as 2C the rod moves down.
As it falls, neaning there 21 is local damage at that point.
22 c.
'*ha t do you mean "neaning there is local 22 damage"?
There's something there that I didn't i
2d tollow.
e 25
. ^.
.eaning that the fiscioning is rol id.
s
] t 'l t:ii.N A T I G !; A L C C L i-I P.i l' C 6 '. i. e i,
3M.
!! C U S T C N, TEyAF (712) 952-Sc11
w.
1 t e r.- n t c r : 1 ;.
..-.srctcs q u i c i.l y.
T!. e rete of it I
increases.
3 C.
What have you described there that is 4
any different from i nc r e a s i ng 1.o w e r level, or 5
A.
Cnly C
C.
increasing fission rate?
7 A.
It's not really, except again, for the e
two conditions.
S 0
Co you've get a rapioly increasing rower
.r.
10, ra te under these conoitions?
11 A.
Pa r t i cul a rl y the high xenon.
12 C.
And then what happenc?
12 A.
You (; c t a r e,r i d increase in power Iron It those particular rocs I
15 O.
All right.
L JG A.
involved.
I i
17 C.
All right.
1 i
18 A.
Probably would be four or perhaps eight, 19
- guess.
20 C.
All right.
21 A.
And you get fuel damage caused by the 22 over -- the local ov e r po we r i ng of those rods.
23 c.
Ho w do you conclude that the fission 2d ra te will be sufficient to cause fuel danage?
25
.\\.
Again, t.C 9 5 coens to state that they 14 'l F. li t-A I 101 A L L C L O. 's b L 14 ti '. t. x ti,
I:4.
II C U S T O N, TEXAS (713) C57-SS11
1 havo co.e close to
- r... u t :.. _nt of reactivity 2
insertion such that they are in danger of 3
exceeding these cafety 3 f.1 1 t s.
4 C.
Where does the ICPE nake reference to S
that?
5 A.
- 'e l l, on the t s. o races that I cited here.
?
C.
Yes.
?
A.
On page 0-2 of tne NUREC 9
Q.
Yes.
10, A.
to you want ce to read sore?
II c.
I just want ze n an ver to
- c. y q u e.s t i o n.
12 I'd like to knot: what event the ACRE has 12 reference to?
14 A.
All right.
15 C.
Th a t you allege cyproached fuel damage.
16 A.
The ACRS was concerned about an event at 17 bresden II which they don't date.
i IP O..
All right.
19 A.
Actually, two events where it said one 20 five second period was recorded.
And then it 21 says a rod c a r.a b l e of causing the one five s e c,o n d 22 period on being withdrawn one notch if uncoupled 23 and stuck in the core this was not an 24 uncougled rod.
This was a coupled rod.
It was 25 jus'. withdrawn unwisely.
I N T E R.V A T I C N A L C C L' F T FEFORTERS, IFC.
li C U S '! C N, TEXAS (712) 552 C.9]1 MMMMMM MMMMMM MMMMMMMM MM MMMMMMMN NNN
1 c.
All right.
2 A.
/nd stuck in the cerc, centinuing on, 3
could, in falling a n u.m h e r of notches, cause a e
_significantly shorter period leading to fuel 5
camage.
F C.
That's just a surnise on the AcrS part.
7 There have been no instances which such events S
have occurred.
5 hey just extrapolated f r ors t l. e 9
tresden events that it might be rossibic; is that It correct?
e 11 A.
Ye s.
Eut they say a determination needs 12 to he nade as to whether the high rod notch worth 12 produced by high xenon concetration extends ever 14 a large enough region of rod n e v e r: e n t te cause 15 fuel damage from a d r o r. r e d rod.
16 C.
Is that your con ten t ion as well?
17 A.
Yes.
le Q.
Th a t ' s a succinct sta temen t of your 19 con ten t io n?
2C A.
Yes.
21 C.
All right.
You have not performed any 22 of_your own calculations in answer to that posed 22 question, have you?
24 A.
No.
25 O.
Al l right.
Pave you examined any of' I h 21. F N A T I C M A L C C I.i n T R E P C h 'l L H E,
INC.
~
li C L' S T C tt, T E.X A E (717) 652-5911 1
'I applicant's analysis on roc r.c t e n
-o r u.
w_
s te 2
life?
3 A.
I don't believe I have, because I'..
not 4
certain there are any.
5 C.
All right.
A A.
Put I don't helieve I have just u n t' e r 7
those things.
I have eyanined rod drop.
?
c.
eut not this particular variety?
9 A.
Not with thic particular condition in L
IC.
rind.
Il C.
All right.
Le t 's go on to your 12 contention on turbine.missles.
13 A.
I n2ec to go to the john before I have a 14 turbine missle.
15 PP.
EIDDLE:
Le t 's taAe a break.
16 l
17 (Short recess) 1 L
IS 19 C.
(Fy Pr. Fiddle)
Let's turn to your 20 contention on turbine missles nunber 47.
21 1.'a v e you exanined applicant's turtine 22 missle analysis?
22 A.
I think that I have.
24 C.
All right.
hould you indentify for nc 25 wha t's in error in that analysis?
I s a ici : w r I c :4i, L tcen1 1,._ F G i'. 0 t i., I:40
!! C US i C N, 1FXAS (712) C52-5911
_)