ML19263D284
| ML19263D284 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 03/20/1979 |
| From: | Stallings C VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Parr O Office of Nuclear Reactor Regulation |
| References | |
| 169, NUDOCS 7903270327 | |
| Download: ML19263D284 (8) | |
Text
.
Ve co VIRGINI A EL ECTRIC %ND PO 4 ER COMP ANY, RICMMOND, VIRGINI A 23261 March 20, 1979 Mr. Harold R. Denton, Director Serial No. 169 Office of Nuclear Reactor Regulation FR/EJL Attn:
Mr. O. D. Parr, Chief Light Water Reactors Branch No. 3 Docket No. 50-338 Division of Project Managenent U. S. Nucicar Regulatory Commission Washington, D. C.
20355
Dear Mr. Denton:
NORTH ANNA POWER STATION - UNIT 1 STARTUP PHYSICS TEST RESULTS - SUPPLEMENTAL INFORMATION Recently, there have been several telephone conversations between members of the NRC and Vepco staffs regarding the power coefficient test results and the Doppler-only power coefficient data that were obtained during the initial startup physics testing program for North Anna Unit 1.
As a result of these conversations, the NRC staff has requested that Vepco supply additional information regarding the interpretation and evaluation of these results.
Enclosed in the attachment is the specific question asked by the NRC staff together with our response.
Should you have any further questions or comments regarding this material, please contact us.
Very truly yours,
[ b)b. ']t gl/
/
1 b
C. M. Stallihgs, Vice President Power Supply and Production Operations cc:
Mr. James P. O'Reilly Office of Inspection and Enforcement Region II Attachments 7003270 3A7
ATTACfDIENT 6
e
Question:
Describe the methodology that was used to evaluate the total power coefficient test data for North Anna Unit 1.
Figure 1, which was presented in the Vepco Startup Physics Test Report for North Anna Unit 1, depicts the mea-curement data and accident analysis acceptance criteria for the Doppler-only power coefficient. Describe the methodology that was used to evaluate this data, and explain why these results are acceptable.
Response
Power coefficient test results are evaluated by determining whether the design values fall within the tolertnce applied to measured values. The measurement uncertainty, associated with individual determinations of total power coefficient is 30%. Table 1 lists the North Anna Unit 1 measured values, allowable range, and design values for total power coefficient. The acceptability of these power coefficient test results was verified by the fact that the allowable range ( 30%), which was applied to the measured values, encompassed the design values.
Since the validity of the design model has been verified by this acceptable comparisen of measured and predicted data, littic significance should be associated with individually measured values of total power coefficient.
The values for the Doppler-only power coefficient are inferred from the measured values for the total power coefficient *and the design values for the mo'derator coefficient. As with the total power coefficient measured results, the tolerance associated with the Doppler-only power coef ficient values is 30%.
This is a conservative measurement uncertainty because the tolcrance is applied on a percentage basis. The resultant uncertainty value, expressed in terms of pcm/% power, that is associated with an individual Doppler-only power coefficient value is less than the uncertainty acsociated with the measured total power coefficient value.
The design and inferred values for.the Doppler-only power coef ficient are given in Tabic 2, As shoun in this tabic, the results are
~
acceptnble sJnce the design values are within the 130% allouabic range that is applied to the inferred values for Doppler-only power. coefficient.
This comparison of neasured and predicted data provides verification of the design model, and no further significance need be associated with individual, inferred Doppler-only power coefficient values.
As indicated in the startup report, there is also an FSAR acceptance criterien that is used to evaluate these results. This criterion is depicted in Figure 1.
Specifically, the criterion that is used is that the best fit line through the individual data points must fall within the limiting values used in the safety analysis.
As indicated by the figure, this criterion was net.
Figure 2 shous the design value. for the Doppler-only power coefficient together with the values used in the safety analysis.
As can be seen from this information, the safety analysis values envelope the design predictions.
In sur. mary, the results of the Unit I tests inave verificd the dcsign models for the pos:cr confficient and the Doppler-only power coefficient.
Additionally, it has been verified that the design Doppler-only power coeffi-cient values are bounded by the limits used in the safety analysis.
e
Tab]a 1 TOTAL POI.'Eli COEFFICIENT Design Value Power Level l
Ifencured Vnlue A11cvable Range (BOL, Ecst-Estimate) 30%
--15.24 pcm/% power 10,67-19.81 pcpi/% power
-14.02 pcm/% power 50%
-12.74 pcm/% power 8.92-16.56 pcm/% power
-13.75 pcm/% power 75%
-13.57 pcm/% power 9.50-17.64 pcm/Z power
-13.39 pcm/% power 90%
-10.70 pcm/% power 7.49-13.91 pcm/% power
-13.31 pcm/% power 9
9 e
9
TABLE 2 DOPPLER-ONLY POWER COEFFICIEI;T Design Value Power Level Inferred Valu~e Allowable Range (BOL, Best-Estimate) 30%
-13.62 pcm/% power 9.53-17.71 pcm/% power
-11.35 pcm/% power 50%
-10.77 pcm/% power 7.54-14.00 pcm/% power
-10.75 pcm/% power 75%
-11.08 pcm/% power 7.76-14.40 pcm/% power
- 9.96 pcm/% power 90%
- 7.59 pcm/% power 5.31-9.87 pcm/% power
- 9.38 pcm/% power t
e 0
W e
k,_
J' O
p p_.;
.g l
r- -
[
d..
/
mn l
t-=
/ i- }
7
-G~;
'.---l t
m
,f
, 4, o
w t
47 D
i, f __ O M
C3
]
z C =-
1 g
,/
EC 1f M
p 2
1
~ %
- t m
c
}
v-I s.
m-E :- Er--_/
s
,c il L.
H I
-I C
t w
I
__[
3-a 1
1
'd g
> I w I r
O U
i L_.
-=-=/_
s M'
i o
Q e ja
.$" d;"
O q _a.
,5.m c
.l:-
_ t -- >
t w
.~
- 7. 7 n
i
-- ~-
s-
.M
- "* = --
N N'--
__ _/,-.._ _ _ b.-1)~f a
EC [b.
7, y
l L.-
y w
W
/
2-
- -= -
4-d ~..'
/-..
W '. e/
- .7 :: < x.
=
r 3 :
---f pg
- 3 f-l-
1 L
~
~
W
/
-i b>
E as t-a f~
>=
q
- a. ~ > a 5'
~
o-M 2 d C D C OO H
/
r g
[
h g -[
__.O [
=
~~
6 [1 %
E
-;*;'=/
l 55 55 i
t
=Og
_._-..j_.
m=
q=
3
-'- ~_:l rp
='N.
L 2
C 2:
1.--
-t =-
n C
/ m- _ _ _ - / =_. _.. - --
g...._ __.__
a 3--
- 2 y
] = =- =.__ _ ~7c__ _-- -_ _. _
p= e._
g g
t!
a c.
_._. / := = _- __
-...- t 3
b
=l '= =.- -. -_^ * = =. - -- - - : - -I :__f l.-: - -- n i r - :
-~ s
-/. = ;
- --/r_ = r r.- :
r 1._._ _ _d o N
C C
v N
O O
C C
.v
.O N
e, e.
4 c.4 1
1 1
1 1
I I
I i
1 (32?.0d %/H3d) J"*1DIl3303 E2.".0d E2'IddOG e
FIGURE 2
_NORT11 ANNA l' NIT I - CYCLE 1 i
DOPPLER POUER COEFFICIENT USED IN ACCIDENT ANALYSIS AND PREDTCTI'D VALUES AT Il0L AND EOL
-20 i
l,
+
1 l
i N. IN-'-
NOTE 1 l<-- -- - I l
-l t-
- I fi
,4 i
~. _
j i
.I i
~
At.
_ _ ~.
p_,l_:_ I' _ _. 2...
l i.
t' w%
..{.
.l.
- l
.-.s'-
l m
i s,
l l
.{
_ __{
i
%'N c
i
-14 I
i
'7 f s; I
t i
N
'l-
- 4w I
i j'
j l
.__.... _ '. __~.
_.. 7 l
d_
I
! 7',:
1
,.1 l
U i
7
' T l'
v"
-12 I
~..l.
i
. _ q.. _.. _ ;,. ~ !.._
IH
_.i.
z t
1 I
m g
~,_ -,,
i l
BOL PREDICTION i
-O
-10 "I-,
.l.
G i{.
~
~
i 4
._..-- NOTE 2p
-p x
'~h ' ' ; j - ' ;-;. l., -
EOL PPEDICTION j
i N
i t
[
. i...
A
.p...,
g 2
-6 y
__.. NOTE 1: " UPPER CURVE" MOs t NEGATIVE l'
_h
.l.
g l
DOPPLER ONLY POWER DEFECT -1.6%AK
_4 m
o j NOTE 2: "LOWEE CURVE" LEAST NEGATIVE I
R DOPPLER ONLY POWER DEFECT -0. 843%AK :
-2
- l a,[;._7 J
].;. _p _g 4I ;
iji i
f T.
.t-7._. _.g _ _m___
q -_.p__ n u
4 I.
l
(
0 0
20 40 60 80 100 POWER LEVEL (%)