ML19209D173
| ML19209D173 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 10/17/1979 |
| From: | Stewart W FLORIDA POWER CORP. |
| To: | Ross D NRC - TMI-2 BULLETINS & ORDERS TASK FORCE |
| References | |
| 3--3-A-3, 3-0-3-A-3, NUDOCS 7910190491 | |
| Download: ML19209D173 (7) | |
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Florida Power
'
- P O 4 A Y IO N October 17, 1979 File:
3-0-3-a-3 Mr. D.
F. Ross, Jr.
Director Bulletins & Orders Task Force Office of Nuclear Reactor Regulation U.S. Nuclear Regulaf.ory Commission Washington, DC 20355
Subject:
Crystal River Unit 3 Docket No. 50-302 Operating License No. DPR-72
Dear Mr. Ross:
Enclosed is Florida Power Corporation's interim response to ltems 3A and 3B of ittachment A to your August 21, 1979 letter.
This response addresses the sources and effect on natural circu-lation of noncondensf 51e gases following a smail break LOCA.
The final response to ltems 3A, B,
C, and D are nearing comple-tion by B&W and will be submitted as soon as possible.
Very truly yours, FLORIDA POWER CORPORATION
'R o
.( occaenu W. P. Stewart Manager Nuclear Operations ECSekcWO2(D70) 11/4 265 791019 47/
General Office 3201 Tnirty-fourtn street soutn. P O Box 14o42. st Petersburg. Fiorida 33733 813-866-5151
STATE OF FLORIDA COUNTY OF PINELLAS W.
P.
Stewart states that he is the Manager, Nuclear Operations, of Florida Power Corporation; that he is authorized on the part of said company to sign and file with the Nuclear Regulatory Commission the information attached hereto; and that all such statements made and matters set forth therein are true and correct to the best of his knowledge, information and belief, c
Ub 1
(Ld.O t
W. P. Stewart Subscribed and sworn to before me, a Notary Public in and for the State and County above named, this 17th day of October, 1979.
t ud\\
,,, i n i j Notary Public Notary Public, State of Florida at Large, My Commission Expires:
August 8, 1983
\\ il,4 2b CameronNotary 3(D12)
f;0NCO'lDEilSIBLE GASES There are two possible ways in which the release of noncondensible gases in the primary system could interfere with the condensation heat transfer processes which occur in the steam generator during small loss of coolant accidents.
If noncondensible gases filled the U bend at the top of the hot leg, then water vapor would have to diffuse thrcilgh the noncondensible gases before they cnuld be condensed in the steam generator.
This would be a very slow process and would effectively inhibit natural circulation.
Lesser amounts of noncondensibles would reduce the heat transfer by condensation because the vapor would have to diffuse through the noncondensibles to get to the condensate on the tubes.
Table 1 lists the potential sources and amounts of noncondensible gases for a 177 fuel assembly plant. However, most of these gases would not be released for small break transients. Appendix K evaluations performed for the 177FA plants demonstrate that cladding temperatures remain low and no cladding rupture nor metal water reaction occur.
Thus, these sources can be neglected.
Also, the steam generator is a heat sink only if primary system pressure is above t 1050 psia.
Therefore, gases present in the core flooding tank can be neglected in addressing the effect of noncondensible on SG condensation.
The only sources of noncondensibles which might separate in the RCS are the ases dissolved in the coolant, the gases in the pressurizer, gases in the maketlp and borated water storage tank and gases released from an allowed 1",
failed fuel in the core.
Thus, the maximum arount of noncondensible gases in the system, assuming. all gas comes out of solution, no noncondensibles are lost through the break flow, that there was ora percent failed fuel, and the injection of 6.4 x 104 lbm from the makeup tank and C',lST (typical of % 1500 sec of HPI),
would be:
Dissolved in coolant 563 scf In pressurizer 166 Fission gas 2
Fuel rod fill gas 11 MU tank 24 BWST 14 Total 780 scf 3
This gas would occupy a volume of 2;.4 ft at a pressure of 1050 psia, the lowest pressure condition in the primary system for which condensation heat removal will occur.
It should be noted that the assumed integrated injection flow does not have a significant effec' on the total volume of noncondensibles which might be present in the primary system. Since the volume required to 3
completely fill the U-bend in the h' t leg is 125 ft, the nom adansible gases will not impede the flcw of vapor to the steam generator.
1174 267
_2-The heat trans fer during condensation is made up of the sensible heat trans-ferred through. the dif fusion layer and the latent hcot released due to congen-sation of +he vapor reaching the interface (see Figure 1).
The model of Colburn and Hougen 1) gives the following equation for the heat transfer in the vapor phase:
4 = hg(Tg - Tg ) + Kg Mg hf(Pg - Pg )
(1) g j
g g
j 2
4 = craensation heat flux, btu /hr f t 2U F hg = heat transfer coefficient for vapor layer, Btu /hr f t Tg = bulk temperature, F
g
= temperature of interface, UF Tgj Kg = mass transfer coefficient, Mg = molecular weight, Ibm /lb mole fg = latent heat of vaporization, Stu/lbm h
Ib f
Pgo = partial pressure of vapor at bulk conditions,' f 2 Pgi - partial pressure of vapor at the interface, lb f ft2
.373 h- ~ O 9
9 = 1.02 D P/pCL1 K
Z 10 pD t
2 D = diffusion coefficient, f t /hr z = height Ib ft f
R = gas constant,1545 lb mole R T
absoiute temperature at bulk candi Lions, OR 2
g = acceleration of gravity, f t/hr 3
p = densi ty, Ibm /f t 3
po = density at bulk conditions, lbm/ft 3
pi = density at interface conditions, lbm/f t p = viscosity, Ibm /hr ft pcm = Pai - D00 pai tn pao pai = partial pressure of gas at interface, I 2
f pac = partial pressure of gas at bulk conditions, h 1174 268 For the application to OTSG condensing heat trrrefer during small break tran-sients, the tern hg(Tg3 - Tgi) can conservative,y oe neglected since the vapor velocities would be very low.
- Tcus, 4 = Kg Mg hfg(Pgo - Pgi).
(2)
The heat trrnsfer with noncondensible gases present is obtained by iteration".
An interface temperature Tgj is assumed, which fixes Pgi, and the heat transfer across the liquid condensate film is computed from 4 = hr(Tg; - T )
(3) g where 3'
II4 P (pf - o )g hfa f k
f g
pf ZO9j-Tj f
g 3
pf = density c f fluid, Ibm /f t ec. =
3 p = dar.sity of vapor. lbm/f t 9
U kf = therm;l cont'uci.ivity o f fluid, Btu /hr f t F T = call tempereinra, F g
The partiel pc:sure of the gas at the bulk cond tions can be calculat2d from the mle fraction of noncondansible gases. When the heat flux cc:,.uted from cauation 2 mdch'.s that caputed by equuion 3, the proper intcrfcce temperature has been found.
The impact of noncontensibles on the condensation heat transfer pre ess du-ing a small break was examir,ad for the 0.04 ft2 and 0.01 ft2 cold leg reaks ancly-zed for the 177-FA plants. The breaks utilize the SG for heat removal for a significant portion of the transient. Hand calculations were performed, using the theory presented above, to ascertain the effect of non-condensibles on the transient.
The amount of noncondansible gases, assuming that all et.ses come out of solu-tion, would b2 2.61 molcs. The effect of these gases is to raise the pressure rod primary tauparature to obtair the same heat transfer. Assuming that the noncondensibles accumulated only within the steam generator upper plenums and the steam generator tubes, the system pressure increase, due to noncondensibles, would only be 25 osi, for a 0.04 ft2 break, and 40 psi, for a 0.01 ft2 break.
It should be noted that this effect is predcminantly due to the inclusion of,d the partial pressure of the noncondnnsibles, which is 24 psi for the 0.04 ft brcat and 34 psi for the 0.01 ft2 break, in th2 total system pressure. The;e calculations represent the maninum impact as they were conputcd at the time of maxiruum condensation heat flux for the respective cases.
As shot n, the influence of noncondcasibles coes not significantly effect the condensation heat transfer process. The estimates made are conservative in that they assumed all the gas is located in the steam generators (none is in the tcp of the reactor vessel or pressurizer) and no gases escape through the break. Thus, the presence of noncondensible gases in the system should not significantly affect the small break transient.
1174 269
FIGUTcE 1 n
Ulf fUS10!! LAYEll w
/
/
l
_p P
If
~ ~ ~ FBo l
a v#,s VAPOR At!0
/
/\\,
P a
/
j a
o Ej
--T
//
' / p g
f
/
,Q T.g' l
/
/'
/{'i l
/(n
,/s C0t:Of.t! SATE
{
33 b
[... _i n
P TOTAL i'i:ESSUT:E f
2 aj PARTliL I'llESSU;'E Of CAS l.T li:lEf.Fi.CE, ib;/it
=
9 Pa Pt.RTI AL Fi: ESSURE Ci GAS AT DUL!; CCl nlTICi:S,lt;;/f t -
=
o 2
Pgj PARTIAL PRESSURE OF VAPOR AT INTERFACE, Ibg/ft
=
2 Pg g PARTI AL PRESSU"E OF VAPOR AT Culf 00 :DIT101:3, Ib;/ft
=
Il,'.L L l Ei h.f,i.TLl:E, "f T
=
u Taj l E!.;fEi' A ii'3 E
'.T li!T'.i:f!:E, 'f
=
Tg BULK TEl.'PER ATURE, F
=
g P Ei._ Zi:0 E :
1) 09 L L U f. !, l.. l'.
f.'.
l:0i'r':;:, D.., "i.U ' Ci' 0 f r.00i.L a C0ll0E! SEi:C iT3 ':i%TUi.CS 0.' YAPC!:S L1Tii 1:0WCEl0E!:S11:'
Cl. 3 E S", 1:". d:9 Ci!:'. 2E(i1), 1;J.
1174 270
m-
.o TABLE 1 S9"RCES CF MCCUD'NSIt'NS - 177 FA PLANT Total rvailable
).
g.,.
n
.y t 1% VETAL-WATER REACTION Individual Individual Individual Individual Total Cas Total Gas Tetal Total Gas Total Total Cas Volume Volenes Hacs Masses
.'.: 1.
Ir.d. Gn
!.a s Masses Vol.
Ind. Cac Mass Passes Source Gas scf s(
- 15.
15.
ec*
Vel. scf 15.
Ib.
scf Vol. sc f 15.
Ib.
Dissolved in reactor H &N 563 11 ~ 39 3 14 "2 ~ 1*7 2
2 2
coolant
- 158
- 12.3 Pressurizer steam H &N 136
- 1 - 65 5.9
!! - 0.4 2
2 2
2 8 Pace N
71 N - 5.5 2
2 Pressurizer water H &N 30
!! - 20 0.91 11 - 0.11 2
2 2
2 "P"#*
N - 10 N - 0.8 2
2 Fission gases in Kr & Xe 186 Kr - 20 65.5 K r - 4. 8 1.9 Kr - c.2 0.66 Kr - 0.05 1.9 core Xe - 166 Xe - f0.7 Ye - 1. 7 Xe - 0.61 Fuel rod fill gas lie & soem 1133 I!c - 1002 14.8 Fe - 11.5 11.3 lie - 10.9 0.15 IIe ! C.12 11.3 N2&02 N2 - 32 N2 - 2.S N2 - 0.3
- 12 - 0.02 02~9 02 - 0.8 02 - C.1 02 - 0.01 Metal water reaction 11 416,500 2320 4165 23.2 2
(100%)
MU tank gas space
!! &N 726
!!; - 421 26.1 112 - 2.3 2
2 6
N2 - 305 N2 - 23.8 MU tank water space
!! &N 24 II2 - 16 0.71 H2 - 0.09 2
2 N2-8 b2 - 0.62 I
BWST Air (N2 1383 N2 - 902 121.2 N2 - 70.3
{
&0) 02 - 481 02 - 50.9 2
i CF tank gas space N,
26,248 2047 (two tanks) j CF tank water space N,
964 75 i
(two tar.ks)
Assemptions 3
1.
ItCS contains 40 std. cc H /K water & 20 std. cc N /Kg water, with water volune = 10,690 f t at 583F and 2200 psia.
~
2 g 2
2.
Pressurizer water contains 40 std. cc II /Kg water & 20 std. ec N /Kg water with l{enry's Law relation between water space and steam space at 650F.
2 2
l Water volume = 825 ft3 and s team volume - 716 f t3 3.
Fission gases based on inventory in core at 292 EFPD.
j 4.
Fuel rod gas based on each rod containing 0.0375. gmol He, 0.0011 cmol N2 and 0.00029 girol/02
~
L 5.
Metal-water reaction based on 52,000 lb. 2r cladding.
Q 6.
MU tank values based en tank containing 200 f t3 3
gas space'and 4C0 ft water space at 120F with the water containing 40 std. cc ll2/Kg and 20 std.
cc N /Kg with llenry's Law relationship between gases in water and in gas space.
y 2
7.
BWST contains 450,000 gallons of water saturated with air, i.e., 15 std. cc N /Kg and 8 std. cc 0 /Ki;-
2 2
' N 8.
Each CF rank contains 1040 ft water and 370 f t gas space with 600 psig N2 at 120F with Henry's Law relation between water and gas.
3 3
N 9.
Values for 1% failed fuel based on Xe and Kr fission product inventcry and fuel Iid fill gas (lie) in 1% of fuel rods being released to coolant.
10.
Values for 1% metal-water reaction based on gas.es in Item 9 above and H2 retc.ned from 1% of Zr cladding (520 lb.) reacting with coolant.
f
.