ML19253B058
| ML19253B058 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 09/07/1979 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | Rubenstein L Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7909140432 | |
| Download: ML19253B058 (11) | |
Text
TENNESSEE VA.LLEY AUTHORITY CH ATTA NOOG A, TENN ES5cE 37.101 400 Chestnut Street Tower II September 7, 1979 Director of Nuclear Reactor Regulation Attention:
Mr. L. S. Rubenstein, Acting Chief Light Water Reactors Branch No. 4 Division of Project Management U.S. Nuclear Regulatory Commission Washington, DC 20555
Dear Mr. Rubenstein:
In the Matter of the Application of
)
Docket Nos. 50-3'!7 Tennessee Valley Authority
)
50-328 Enclosed is our response to the Reacter Systems Branch question on Net Positive Suction Heat (NPSH) calculations for the ECCS pumps transmitted by your letter to H. G. Parris dated August 23, 1979.
This response will be incorporated in Amendment 62 of the Sequoyah Nuclear Plant Final Safety Analysis Report as question 6.63.
Very truly yours, TENNESSEE VALLEY AUTHORITY
~.
,~
~
,._. _ m
~L. M. Mills, Manager Nuclear Regulation and Safety Enclosure 3433M s5
\\
k 7 90014 0 V32 An EcuM Cccer tumty Emclo,er
ENCLOSURE 6.63 Reactor Systems Branch (212.0)
Provide the following information to resolv'e the staff's concerns whether sufficient NPSH is available to RHR pumps during a worst-case flow condition:
(a) Show that the kinetic head loss term (V /2g) has been appropriately factored into the NPSH analysis by identifying that it was included in the pump manufacturer's speciff. cation of required flow, or by including it in the calculations provided.
(b) Provide preoperational test results which demon-strate that for a worst-case flow condition flow through the as-built RHR pumps will not exceed that assumed in the analysis (4500 gallons per minute).
Include discussion (s)/ data interpretation to verify the worst-case flow condition (i.e., address the RHR auxiliary containment spray) from the sump and to confirm that sufficient NPSH is available to the ECCS pumps.
Response
(a) The kinetic head contribution to suction head for the RHR pumps was included in the manufacturers NPSH test curves which were individually determined for each pump.
(b) Refer to the " Revised NPSH Calculations for the RHR and Contair. ment Spray Pumps Operating in the Recirculation Mode" as revised August 23, 1979, to account for RHR flow rate of 5500 gpm (attached).
3dbO'N5
REVISED NPSH CALCULATIONS FOR THE RHR Ala CONTAINMENT SPRAY PUMPS OPERATING IN THE RECIRCULATION MODE REVISED AUGUST 23, 1979 to Account for RER Flow Rate of 5500 gpm a
+
l t.
, 7,
- b m ul uu) m.[,l I "jj
'k I n t
Objective The purpose of these calculations is to confirm that the net position suction head available (NPSHA) exceeds the net positive suction head required (NPSHR) for the residual head removal (RHR) and contained spray system (CSS) pumps under worst case ECCS conditions.
Conditions 1.
Physical configuration of piping as per isometric sketch, figure 1, 2.
Both RHR and both CSS pumps operating at rated flow ( 5500 gpm and 4750 gpm respectively),
3.
NPSHR for the pumps as per figure.s 2 and 3, 4.
Maximum water temperature 160 F (per FSAR fig 6.2-31),
5.
Containment post-LOCA pressure, atmospheric (P = 14.7 psia),
6.
Containment flooded to elevation 693'0" (technical specification minimum injection volume and ice melt per FSAR figure 6.2 -3/c).
References 1.
"Model Study of the Sequoyah RHR Sump," TVA Report No. WM 28-1-45-102, October 1978.
2.
" Flow of Fluids Through Valves, Fittings, and Pipe," Technical Paper No. 410, Crane, 1969.
Calculations The NPSH is the total suction head (absolute at the impeller eye) minus the vapor head (absolute) of the liquid being pumped.
NPSH = h
-h
+h
-h (1) a vp a-st fs where:
h,
= atmospheric head, absolute pressure (in feet of liquid) on the surface of the liquid being pumped.
H
= vapor head, the head in feet corresponding to the vapor "E"
pressure of liquid at the temperature being pumped.
h,
= static head, static height in feet that the liquid s"
supply lebel is above the impeller eye.
friction head, all suction line losses (in f eet) including h
=
fs all sump screen and form losses, and friction losses through pipe, valves, and fittings.
1 l
343 m
Of these, the atmospheric head is the product of the containment pressure and the specific volume.
h, = 14.7 x 144(0.01639) = 34.694 ft.
160 F and The vapor head is the product of the saturation pressure at the specific volume.
h
= 4.7414 x 144(0.01639) = 11.191 ft.
As defined above, the static head for the RiiR pumps is:
h,t = 693'0" - 655'7-1/2" = 37'4-1/2" and for the CSS pumps:
h
= 693'0" - 656'0" = 37'0" The friction head loss is the sum of sump screen and form losses and the pipe, valve, and fitting losses. Of these, the loss through the sump, beginning at, and including the inlet screen and ending at, and including the discharge pipe inlet, may be computed using:
- z.,
h
=C 2
sump L 2g where:
C. = the sump loss coefficient as determined in the physical model tests at Norris Engineering Laboratory Gleference 1)
V' and
- - = the velocity head in the discharge pipe
-8 given C, = 0.45 u
and an IS" sch 10 outlet pipe 13.675 f t/sce then V = flow rate =
(20500)(144)(4)
=
3 (7.48)(60)(3.1416)(17.5)"
area and h
= (0.45)(13.675 )~ - 1.306 a sep (2)(32.2)
~
The friction losses for the com:non piping are greatest in the longer length, W to X in figure 1.
Losses in this section computed using reference 2 are:
Straight pipe:
34' of 18" sch 10 42' of 18" sch 40 76' of 18" sch 40 (used for calculations)
Fittings: LR 90 elbow (2)
L/D = 20 L = 28(2) = 56' LR 50 elbow (1)
L/D = 12 L = 18' Tee - run (1)
L/D = 20 L = 2S' Total = 120' of IS' s un 2.0 fg*y qf_.}
R
/j O p(;R @bI{ bN oUjd i
t a
Valve:
fully open gate, L/D = 13 L = 19' of 18" sch 40 Water properties:
P
= 14.7 psia T
= 160 F 3
p
= 60.99 lb/ft
.41 centipoise u
=
Re = 50.6 Qp = 50.6 (5500 + 4750) 60.99 du 16.876 (0.41) 0
= 4.57 x 10 (fully turbuledt) f
= 0.0138 2
h
= 0.0311 fLQ y
5 d
= 0.0311 (0.0138) (76 + 102 + 19) ( 10250 )
5 16.876
= 6.483ft.
The friction losses to the RER pump are greatest in the longest length, B to C in Fig;ure 1.
Losses in this section computed using reference 2 are:
Straight pipe:
36' of 14" sch 40 Fittings:
LR 90' elbow (3) L/D = 20 L = 22 (3) = 66' 45' elbow (1) L/D = 16 L = IS' Tee - run (1) L/D = 20 L = 22' Total = 106' of 14" sen 40 Treat the 18" x 14" reducer as a contraction 1 = 13.124 = 0.78 E
16.876 t
K = 0.15 4D = 12 L = 14' Water properties:
P, T, p, u as above 50.6 u _ 50.6 (5500 ) (60.99)
Ile
=
13.124 (0.41)
= 3.15.c 106 (turbulent) 0.0148 f
=
h,= 0.0311 (0.0148) (36 + 106 + 14) 5500~
BL 5
13.124 5.57 f t
=
3433<10 The friction losses to the CSS pumps are greatest in the longest lengt..
X to Z in Figure 1.
Losses in this section computed using reference 2 are:
12" straight pipe:
41' of 12" sch 40 12" fittings:
LR 90 elbow (2) L/D = 20 L = 2(20) - 40' Tee - leg (1)
L/D = 60 L = 60' 12" x 20" Reducer (expand) K =.4 L/D = 30 L = 30' Total 130' of 12" sch 40 Valve:
fully open gate L/D = 13 L = 13' Water properties:
P, T, p, u as above Re = 50.6 Qp -_ 50.6 (4750) 60.99 du
'11.938 (0.41)
Re = 2.99 x 106 (turbulent) f = 0.0144 hxzi2,, = 0.0311 (0.0144) (41 + 130 t 13) (4750) 5 11.938
= 7.67 ft 20" straight pipe:
25' of 20" sch 20 20" fittings:
LR 90* elbo -
(2) L/D = 20 T. = 2(32)
= 64' 20" x 16" reducer K = 0.12 L/D = 10 L = 16' 20" Tee - run L/D = 20 L = 32' Total 112' of 20" sch 20 Water properr.ies:
P, T, p, u as above Re = 50.6 Qp _ 4750 (60.99) du.
- 19.25 (0.41)
Re = 1.86 x 106 (turbulent) f = 0.0158 xz20,, = 0. 0311 (0. 0158) (112 r 25)
U. i5 v h H
e 19.25
= 0.58 ft, h
=H
,, + h
'D
- U' g
xz20" kfY yD. 3 $
seaso id f h
i i
,i i
<.i
.n o
U U j b. JtjLl3CL_3
_4_
Summary of friction losses in feet:
Item RHR Pump CSS Pump Sump (including screen loss) 1.306 1.06 Common pipe (W to X) 6.483 5.28 RHR Suctien pipe (B to C) 5.57 CSS Suction Pipe (X to Z) 8.25 h
(t tal) 13.36 14.59 fs Therefore, from (1):
NPS -
=H
-h
+h
-h a
vpa st fs
= 34.694 - 11.191 + 37.375 - 13.36
= 47.376 ft.
and NPSHA
=h
-h
+h
-h.
CSS a
vpa se Is
= 34.694 - 11.191 + 37.0 - 14.5c
= 45.91' ft.
The NPSIm is 34 ft. from Figure 2.
gg and The NPSHR is 17.0 ft. from Figure 3.
CSS Conclusion The above calculations show that:
1.
The R}{R pumps available suction head exceeds the minimum required by at least 13.4 ft.
Excess head bHR ~
biR.
~
= 13.4 ft.
The CSS pumps available suction head exceeds the minimum required by at least 28 ft.
Excess head
= NPSHA
~
= 28.913 ft.
G..i D Y s b '
ELEVATIONS:
20"x iP."x 20" A,W S'JMP OUTLET EL 669'-8-3/16" TEC (TYP)g RHR PUMP SUCTION EL 655'-7-1/2"
,20"x l 2" C,Y RED (TYP) 0,Z CONT SPRAY PUt'P FL 656'-0" SUCTION
\\
=0 DISTANCES:
30' 0F 18" SCH 10 + 38' 0F 18" SCH 40
--J;"
AB 3G' 0F 14" SCH 40 r_, aj DC 37' 0F 12" SCH 40 + 21' OF 20" SCH 20 rm 7
BD 34' 0F 18" SCH 10 + 42' 0F 18" SCH 40
{g_.9 -
c
'n WX 31' 0F 14" SCH 40 h ': ~S XY 41' 0F 12" SCH 40 + 25' 0F 20" SCH 20 XZ EirT r
ljh]
g f
%a ti g
NOTES:
[18"x12"xl8"
- 1. ILLUSTR ATIVE ONLY, N TEE (TYP)
TO SCALE.
AJ
- 2. ALL BENDS ARE 90 X
-l 50 ELL UNLESS OTHERWISE A (45 ELL e
y k
B 4 ' ' F L L ;,7-18"x 14" ECC RED (TYP)
((
14" Si o I EE (TYP)
A 00 C
C E5 k
'"'"* '-
1 I
' O O
t
- o 0
i 8
O O
O D
O M
D CL 1
O
._ o O
9 acL.
W
.c 1
O b<
W I
O
- o
!n d<
D O
W Z
c I
O
~i O
(\\}
}N gi Cr O
I.
O
'7 u^
O O
O O~
m rq N
N (1.d) HSd N 0381nO3B n nw[lllu;_;
u bLil.)j(u;h[
34333,3
OO
- O co oo
- os Q.
2 O
D CL o
>I 1
CC c-O CD F-8 z
~ c Ld c
eet Z_
<I i-Z O
0
.c
- 0o I
7 10 Ld re
{
E s
O L.
a e
o O
C 9
m n
a m
(13)
HSdN G3'alnC3B 3430154