ML18144A028
| ML18144A028 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna, 05000000 |
| Issue date: | 11/19/1985 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Harold Denton, Thomas C Office of Nuclear Reactor Regulation |
| References | |
| 85-753, NUDOCS 8511250319 | |
| Download: ML18144A028 (39) | |
Text
~*
f,,*
e VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 November 19, 1985 W. L. STEWART VxcE PRESXDENT NUCLEAR OPERATIONS Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation Attn:
Mr. Cecil 0. Thomas, Chief Standardization and Special Projects Branch U.S. Nuclear Regulatory Commission Washington, D. C.
20555 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY SURRY AND NORTH ANNA POWER STATIONS REACTOR SYSTEM TRANSIENT ANALYSES Serial No.85-753 E&C/NAS:asp Docket Nos.:
50-280 50-281 50-338 50-339 License Nos.: DPR-32 DPR-37 NPF-4 NPF-7 In our letter to you of April 14, 1981, Serial No. 215, we transmitted our Topical Report VEP-FRD-41, 11Vepco Reactor System Transient Analysis Using the RETRAN Computer Code.
11 The report, which was provided for review by your staff, describes the system transient analysis capability which Vepco is using in support of core reloads, and other operational or design changes at our nuclear units.
Following a request for supplemental information, to which Vepco responded with letters dated February 27, 1984, July 12, 1984 and August 24, 1984, the staff issued a letter approving the report for referencing in license applications on April 11, 1985.
In the Safety Evaluation Report (SER) accompanying this approval, the staff referred to Vepco 1s RETRAN capability "for performing transient analyses using the RETRAN01/MOD03 Computer Code.
11 Since no RETRAN02 analyses were presented in the topical report or the supplemental submittals, no reference to Vepco 1s use of RETRAN02 was made in the SER.
Vepco has informally discussed its desire to have the SER for VEP-FRD-41 extended to RETRAN02/MOD03 applications informally with your staff (Mr. J. Guttmann, USNRC Reactor Systems Branch and Mr. D. Moran, USNRC Standardizations and Special Projects Branch) on April 2,
1985.
Based on that discussion, we are submitting for your review an additional set of analyses performed by Vepco with the models documented in VEP-FRD-41 and the supplements discussed above.
These analyses provide comparisons of results obtained for identical transients using RETRANOl (the code version used to perform the analyses presented in VEP-FRD-41) and RETRAN02.
As discussed in the attachment, the results are very nearly identical except in the area of nonequilibrium pressurizer behavior, where substantial improvements were made in the solution scheme in RETRAN02.
i
Mr. Harold R. Denton Page 2 e
We are requesting, based on these results, approval to reference VEP-FRD-41A and the associated SER in future licensing applications involving Surry and North Anna Power Stations where analyses have been performed using the RETRAN02 Computer Code.
In order to support upcoming licensing submittals, we request your approval by February 1986.
Very truly yours, Attachment cc:
Dr. J. Nelson Grace Regional Administrator Region II Mr. H_a ro 1 d Berna rd Standardization and Special Projects Branch Mr. J. L. Carter Reactor Systems Branch Mr. J. Guttmann Reactor Systems Branch Mr. Steven A. Varga, Chief Operating Reactors Branch No. 1 Division of Licensing Mr. Edward J. Butcher, Acting Chief Operating Reactors Branch No. 3 Division of Licensing Mr. D. J. Burke NRC Resident Inspector Surry Power Station Mr. M. W. Branch NRC Resident Inspector North Anna Power Station
e ATTACHMENT 1 COMPARISON OF RETRAN01 AND RETRAN02 COMPUTER CODE RESULTS 1
e TABLE OF CONTENTS Title Page LIST OF TABLES......................................... 3 LIST OF FIGURES.....................................
4 1. 0 INTRODUCTION....................................
6 2.0.DESCRIPTION OF MODEL.............................
7
- 3. 0 RESULTS OF ANALYSIS............................... 8
- 4. 0 CONCLUSIONS..................................... 10 5. 0 REFERENCES...................................... 11 2
e LIST OF TABLES No Title Page
- 1. Initial Conditions for Steady-State Operation........ 12
- 2. S ignif icari t Events During Reactor Trip Transient..... 12
- 3. Significant Events During Turbine Trip Transient..... 13
- 4. Significant Events During Loss of Flow Transient..... 13 3*
e LIST OF FIGURES Reactor Trip No Title Page la. Midcore Heat Flux.................................. 14 2a. Nucl*ear Power...................................... 15 3a. Midcore Fuel Temp.................................. 16 4a. Heat Extraction.................................... 17 Sa. Steam Pressure..................................... 18 6a. Inlet Temperature......................... -......... 19 7a. Pressurizer Pressure._.............................. 20 Ba. Loop Flow.......................................... 21 Turbine Trip No Rx Trip No Title Page lb. Midcore Heat Flux.................................. 22 2b. Nuclear Power...................................... 23 3b. Midcore Fuel Temp:................................. 24 4b. Heat Extraction.................................... 25 Sb. Steam Pressure................................ _..... 26 6b. Inlet Temperature...................... *............ 27 7b. Presiurizer Pressure.. :......... ~.................. 28 Sb. Loop Flow....... -....... :............................ 29 4
e e
LIST OF FIGURES (CONT.)
Loss of Flow No Title Page le. Midcore Heat Flux....................... *........... 3b 2c. Nuclear Power...................................... 31 3c. Miclcore Fuel Temp.................................. 32 4c. Heat Extraction................................ ;... 33 Sc. Stearn Pressure..................................... 34 6c. Inlet Temperature....................... ;.......... 35 7c. Pressurizer Pressure........................ ~...... 36 Sc. Loop Flow....... _.................................. _.. 37 5
e
1.0 INTRODUCTION
Virginia Electric and Power Company (the Company) has performed analyses to compare the results calculated by RETRANOl and RETRAN02, two versions of the RETRAN computer code which have been released by the_ Electric Power Research Institute (EPRI).
Topical reports related to RETRAN have been submitted by the Utility Group for Regulatory Application and have been accepted by the NRC (Refer-ence 1).
The NRC approved the Company's lice_nsing topical report VEP-FRD-41A,"Reactor System Transient Analyses using the RETRAN Computer Code",
on April 11, 1985 (Reference 2). The analyses presented in VEP-FRD-41A were per-formed using RETRANOl. Since the Company intends to use RETRAN02 for its licensing analysis,
- the NRC requested comparative analyses ustng RETRANOl and RETRAN02 to support extension to their review and approval to RETRAN02 (Referen~e 3).* The three transients that were selected for this comparative study were:
- 1. Reactor Trip
- 2. Turbine Trip without Reactor Trip
- 3. Complete Loss of Flow These transients demonstrate the significant features of the models (nonequi-librium pressurizer behaviour, point kinetics response, response to large flow variations, etc.) but are straightforward enough that differences in paramenter trends are readily identified and assessed.
Section 2 describes the models used for the analysis. Sections 3 and 4 contain.the results and conclusions.
6
e
- 2. DESCRIPTION OF MODEL Two RETRAN input decks, a North Anna Single Loop Model compatible with RETRANOl and a similar model compatible with RETRAN02, with nineteen control volumes and twenty-nine flow junctions were used for this analysis. A general description of these models was provided in References 4-7. RETRAN02 is an extension of RETRANOl containing additional user conveniences, the ability to optionally model addi-tional phenomena and upgrading of.some of the RETRANOl models. RETRAN02 can be used with the same options available in RETRANOl with the exception of the follow-ing changes which represent an upgrade of the RETRANOl models:
- 1. A revised solution technique for the nonequilibrium pressurizer model.
- 2. Analytical expressions for water properties (as opposed to a table).
- 3.
The use of junction flow and fluid properties for the wall friction calculation.
Only the minimum changes required to convert the RETRANOl data deck to RETRAN02.
were made. Initial conditions for all transients are shown in Table 1.
7
e
- 3. RESULTS OF ANALYSIS Comparison of the time zero edits shows that the two versions of RETRAN calculate steady state 'initialization parameters which match to within less than 1%. The transient results are described below.
- a. Reactor Trip The reactor was tripped at 0.0 second and the transient was executed for 10 seconds. Figures la through 8a show that the results of the two calculations are essentially identical except for pressurizer pressure. The difference in pressur-izer pressure is due to the revised nonequilibrium pressurizer model_ solution technique. The significant events during the reactor trip transient are listed in Table 2.
- b. Turbine Trip The turbine was tripped at 0.0 second and the transient was executed for 10 seconds. Again figures lb through 8b show that,the results of the two calculations are essentially identical except for pressuriz~r pressur~. The pressurizer pres-sure increases more rapidly during the transient in RETRAN02 than in RETRANOl, due to the revise1 nonequilibrium pressurizer model solution technique. The signif-icant events during the turbine trip are listed in Table 3.
8
e
- c. Complete Loss of Flow The pumps,.. were tripped at O. 0 second and the transient was executed for 10 sec-onds. Figures le through Be show that the results of the tw6 calculations are identical except pressurizer pressure.
The primary coastdown flow rates calcu-lated by the two versions of the code are essentially identical. The significant events occuring during the loss of flow transient are listed in Table 4.
9
4.0 CONCLUSION
S The results of the three transients analyzed above using RETRANOl and RETRAN02 show that the two codes produce essentially identical results except the primary side pressure calculation.
The secondary side pressures predicted by the two codes are essentially identical. The following conclusions can be reached:
- 1. Steady state calculations show less than 1% difference in such parameters as temperatures, pressures and enthalpies.
- 2. RETRANOl and RETRAN02 predicted essentially identical flow coastdown for the loss of flow transient using the same model and initial conditions.
- 3. RETRAN02 predicts larger and faster changes, in the primary side pressure than RETRANOl. This is primarily due to the revised solution technique for the nonequi-librium pressurizer model.
10
e
5.0 REFERENCES
- 1.
Letter from C. 0. Thomas (NRG) to T. W. Schnatz (UGRA),
"Acceptance for Referencing of Licensing Topical Reports EPRI CCM-5, 'RETRAN-A Program for One Dimensional Transient Thermal Hydraulic Analysis of Complex Fluid Flow Systems,' and EPRI NP-1850-CCM, 'RETRAN02-A Program for One Dimensional Transient Thermal Hydraulic Analysis of Complex Fluid Flow Systems, 111 September 4, 1984.
- 2.
Letter from C. 0. Thomas (NRG) to W. L.Stewart (Vepco),
Acceptance for Referring of Licensing Topical Report VEP-FRD-41, "Vepco Reactor System Transient Analysis Using the RETRAN Computer Code", April 11, 1985.
- 3.
Conference between R. M. Berryman, K. L. Basehore and N. A. Smith (Vepco) and Messrs J. Guttmann and Chiu Liang, USNRC Reactor Systems Branch and D. Moran, USNRC Standardization and Special Projects Branch, Bethesda, Md., April 11, 1985.
- 4.
Vepco Topical Report, VEP-FRD-41A, "Reactor System Transient Analyses Using the RETRAN Computer Code", submitted by letter from W. L. Stewart (Vepco) to H. L. Thompson, Jr. (NRG), Serial No. 85-77, July 3, 1985.
- 5.
Letter from W. L. Stewart (Vepco) to H. R. Denton (NRG), "Vepco Reactor System Transient Analyses", Serial No. 060, February 27, 1984.
- 6.
Letter fromW. L. Stewart (Vepco) to H. R. Denton (NRG), "Vepco Reactor System Transient Analyses, Serial No. 376, July 12, 1984.
- 7.
Letter from W. L. Stewart (Vepco) to H. R. Denton (NRG), "Vepco Reactor System Transient Analyses", Serial No. 376A, August 24,1984.
11
e Table 1. Initial Conditions for Steady-State Operation Parameters Value Units Core Power 2830. 50 Mwt Total Loop Flow 104.25E+6 lb/hr Pressurizer Pressure 2220 psia Enthalpy at Lower Plenum 551. 20 btu/lb Steam/Feed Flow 12.464E+6 lb/hr Steam Pressure 856. O_
psia Feedwater Enthalpy 418.50 btu/lb Table 2. Significant Events During Reactor Trip Transient Event Steady State Initialization Steady State Operation Reactor Trip Turbine Trip Pressurizer Heaters on
+10%
Atmospheric Relief Valves Open Setpoint Value N/A N/A N/A N/A Controller Span 1050 psia Time(seconds)
RETRANOl RETRAN02 0.0 0.0 0.0 0.0 0.0 0.0 2.005 2.005 3.445 3.429 9.440 9.379 12
Table 3. Significant Events During Turbine Trip Transient Event Steady State Steady State Turbine Trip PORV Open #2 Initialization Operation 50% of Setpoint Value N/A N/A N/A Controller Span Atmospheric Relief Valves Open 1050 psia PORV Open tJl 2350 psia Time(seconds)
RETRANOl RETRAN02 0.0 0.0 0.0 0.0 0.0 0.0 4.765 4.563
- 6. 610 6.552 6.695 6.393 Table 4. Significant Events During Loss of Flow Transient Event Steady State Initialization Steady State Operation Pump Trip Low Flow Trip Reactor Trip PORV Open #2 50~~ of Turbine Trip Pressurizer Heaters on
-10~~ of Setpoint Value N/A N/A N/A 25194.0 N/A Controller N/A Controller lb/sec Span Span Time(seconds)
RETRANOl RETRAN02 0.0 0.0 0.0 0.0 0.0 0.0 2.140 2.138 3.140 3.138
'i':;':;':;':'i':
4.882 5.145 5.138
- 8. 770 8.941 13
'I.
1. 2 1. 1 C
1 *. G 0
R E
0,9 H
E A
T 0.8 F
L u 0.1 X.
F R
0.6 A
C T
1 o.s 0
N 0
0.4 F
J N 0.3 J
T J
A 0.2 L
0.1 o.o 0
2 FlGURE Ja RE.ACTOR TRIP e
MIDCORE HEAT FLUX 3
RETRANO 1 VS RETRA.N02 4
5 6
T H1E I SECONDS l
- RETRR~Gl:X RETRRN02:SOURRE 7
B 9
10
120 110 N JOG u
C L
E 90 A
R p
80 0 w E R 70 F
R 60 A
C T
J 5G 0
N 0
40 F
J N
30 l
T l
A 20 L
10 0
0 2
FlGURE za REACTOR TRIP NUCLEAR POWER 3
RETRAN01 VS RETRAN02 4
5 6
T J HE !SECOND5l RETRAND,=X RETRRNO~=SOJRRE 7
e 9
10
\\,
2000
\\900
\\800 1100 F u E 1600 L
l E 1 so*o t1 p E
R 1400 A
l.
u R 1300 E
F \\ 200 1100 1000 900 0
1 2
e FIGURE 3a RE.ACTOR TRIP MIDCORE FUEL TEMP 3
RETRANOJ VS.RETRANOZ I
4 5
6 lJ t'IE t5ECONDSI RETRFlNOi=X
~ETRRN02~soJFlRE.
7 8
9 10
1. 2 1. 1 1-j E
1
- G A
T E o.s X T R
A 0.6 C T 1
0 0.1 N
F 0.6 R
A C T 0.5 J
0 N
0,4 0
F l
0.3 N
1 T
J 0.2 R
L
- 0. 1 o.o 0
e FIGURE 4-a REACTOR TRIP e
SG HEAT EXTRACTION RATE 2
3 RETRANO! VS RETRAN02 4
5 6
T J NE l 5ECOND5 l RETRRNOl=X RETRANG2=SQURRE 7
6 9
10
.l
e 1100 5
T E
A 1050 t1 p
R E
5 1000 s u R
E 950 p
5 J
A 900 0
2 P'IGURE sa REACTOR TRIP STEAM PRESSURE RETRANOJ VS RETRAN02 3
4 5
6 7
TJHE !6ECON0Sl RETRR~Ol='X RE 1 RRN02 = SCvR~E B
9 10
~-*
. J N
L E
560 T 560 T
E t1 p E
R R
T U 540 R
E F
520 P'lCURE 6a REACTOR TRIP INLET TEMPERATURE RETRANOl V~ RETRAN02 500-ti:;:;::;:;:==::;::;:::::;::;;::=::;:;:;::::::;::;:::;::;::::;:::;:;::;:;;:;::;:::::;:;:;;:;::;:;:;::;:::;:;::;:::::;::;::::;::;::;:;:;;::;::;::::;::;:::;:::::;:::=::;:;;:;::::::;::;::::::;::;;;::::=:;::t Ci 2
3 4
5 6
T H1E l SECONDS l RETRA!,j01 ::X RETRAN02:SCJARE
. 7 6
9 10 lS
i,.
2200 p
R E 2175 5
5 u R
I 215G z
E R
p 2125 R
E 5 s*
U 2100 R
E p 2075 s
I Fl 205G FJCURE 7a REACTOR TRIP PRESSURIZER PRESSURE JU:TRAN01 VS RETRA.N02 Tlt1E !SECONDS\\
RETRRN01:X RETRR~C2:5CuRR.E 2:
l. 2 l. 1 1, 0 L
. tl 0 o.s p
F L
O.B 0 w 0.1 f
R
.R C
0,6 T
I 0
N 0,5 0
f
- 0. 4 N
0 t1 J
0.3 N
R L
0.2
- 0. 1 o.o I
0 2
3 FJGURE &a REACTOR TRIP LOOP FLOW RETRANOl VS RETRAN02 4
5 6
T ll'IE !SECCND£l RETRAN01:X RETRA~OZ:SG:UR~t 7
B 9
10 Z_i
- l. 2 l. 1 C
l. G 0
R E. 0.9 H
E A
T Q.B F
L u 0.1 X.
F R,0,6 A
C T
J Q.5 0
N 0 o.*
F J
N Q.3 J
T J
A 0.2 L
0, l o.o 0
2 FIGURE lb TURBIN! TRIP NO RX TRIP MIDCORE HEAT FLUX RETP.ANOl VS RETRAN02 3
5 6
7 T J ME !SECONDS I RETRA'-101 :X RE TRC\\NO, :S(h/R~E 8
9 l 0
,.,~
C {_
120
\\ l 0 N 100 u
C L
E 90 A
R p
80 0
M E
R 10 F
R 60 A
C T
j so 0
N 0
40 F
I N
30 J
T J
A 20 L
10 0
0 2
FlGURE 2 b TURBINE TRIP NO RX TRIP NUCLEAR POWER 3
RETRANOl VS RETRAN02 4
5 6
T J ME I SECONDS i fiETRRNC"::X RE: C::C."iG2 :S(h!RR[
1 8
9 10
2000 1900
}600 1700 F u E 16GO L
T E 15GO M
p E
R 1400 A
T u R 1300
[
F 1200 1100 1000 900 0
2 FIGURE 3b TURBINE TRIP NO RX TRIP MIDCORE FUEL TEMP 3
RETRAN01 VS RETRAN02 4
5 6
T H'IE t6ECON0Sl RETRANOl=X RE1RRN02=5C-i.JARE 7
6 9
iO
l. 2 l. 1 H
E 1. G A
T E o.s X
T R
A G.8 C
T l
0 0.7 N
F 0.6 R
A C
T o.s l
0 N
Q.4 0
F I
0.3 N
I T
I 0.2 A
L 0._ 1 0. ()
0
-- ~----
- FIGURE fb TURBINE TRIP NO RX TRIP SG HEAT EXTRACTION RATE 2
3 RETRA.NOl VS RETRAN02 4
5 6
TIME I SECONDS l RETfiANOi=X RETRRN02=S~URRE 7
8
- 9.
10
l 5
T E
R
'1 p
R
[
s s u R
[
p 5
l R
I - -
I e
1100 1050 1000 95Ci 900 FIGURE ~b TURBINE TRiP NO RX TRIP STEAM PRESSURE RETRANOl VS RETRAN02 lJME !SECONDS!
REfR~N01 =X.
RETRAN02::SQJRP..E 2E
l J
N L
E T
T E
t1 p E
.R A
T u R
E F
e FIGURE 6b TURBINE TRIP NO RX TRIP
. INLET TEMPERAtURE RETRA.NOl VS RETRJ.N02 600-U---------~-------------~
580 560 540 520 Jlt1E !SECONDSi RETRFlN01:X.
R.E TR FlN02: 5 t-ul=IR E 27
2350 P 2300
-R E s 5 u R *2250 J z E
R P
2200 R
E 5 s u R 2150 E
p 5
J 2100 A
. 205G FIGURE 7b TURBINE TRIP NO RX TRIP e
PRESSURIZER PRESSURE RETRANOl 'V$ RETRAN02 2000-ti:::;;;;:;:;::;::;:;;;:;::;:;::;:;::::;:;::;:;:;:;::;::::;::;::;:;::;::=:;::;:::;::;:::::::::;:;::;:;::;:;::;::;:;:;::;:;:;::;:;:::;:;::===:;::;::;::;:::::;:::;:;::;:;:;:===;::;:::===~
- 0.
2 3
4 5
6 TJHE ISECOND.Sl HJRRNGi:X
~ETR!=!"IGZ=S~uRRE 7
6 9
iO 2E
,t'.
FlGURE 8b TURBINE TRIP NO RX TRIP LOOP FLOW RETRANOl VS RETRAN02 l. 2 1. i 1. G L
0 0 o.s p
f L o.e 0
lol 0.7 F
R A
(
0.6 l
l 0
N o.s 0
F 0,,4 N
0 M
J Q.3 N
A L
0.2
- 0. 1 o.o 0
2 3
4 5
6 7
6 9
l 0 T 1"1E !SECONDSl RET!s.C',/~l=X RE TF.RI\\~~ =Hlv.c;*,[
29
l. 2 1. 1 C
- i. G 0
R E o_.9 H
E A
T 0.8
. f L u Ci *,
X.
F R
0,6 A
C T
l o.s 0
N 0
0.4 F
J N
0-3 J
T J
A 0.2 L
- 0. l o.o 0
2 FlGURE IC LOSS or Fl.Olf e
MIDCORE HEAT FLUX 3
RETP.ANOl VS RETRAN02 4
5 6
TJHE 16ECON05l RElRR"IOl:.X RE1RRN02=S0iJR"E 8
9 10
120 110 N 100 u
C L
E 90 A
R p
BO 0..
E R
'10 f
R 60 R
C T
J 5G 0
N 0,o f
J
~
30 J
T J
A 20 L
10 0
0 2
F'ICURE 2C LOSS OF YLO'I NUCLEAR POWER 3
RETRAN01 VS RETRAN02
,4 5
6 TJHE !5ECON0Sl RElRRNCl::X RETRRND,::SGvP.'\\E 7
6 9
iO 3i
j 2000 1900 1800 1700 F u E 1600 L
T E 1500 P1 p E
R 1400 Fl T u R 1300 E
F 1200 1100 1000 900 0
-~--- --------------------------
e P'lGURE 3 C LOSS Of FLOY MIDCORE FUEL TEMP 2
3 RETRANO l VS RE'I'RAN02 _
4 5
6 T J t1E l6ECOND5l RETRR~~l=X RE.TRRNG2=St;uR~E.
7 e
9 i 0
- -L 1. 2 1. l H
E 1. 0 R
T E
o.9 X
T R
R 0,6 C
T J
0 0,7 N
f 0,6 R
R C.
T o.s J
0 N
0.4 0
f J
0-3 N
J T
J 0.2 R
L
. 0, 1 o.o 0
. 1 FlCURE,c LOSS or FLOW
.SG HEAT EXTRACTION RATE RETRANOl VS RETRAN02 2
3
. 4 5
6 7
6 TIME I SECONDS\\
R[TRAN01 =X.
RETRAND2:SGUP.RE 9
10 3:.
1100 s
T E
Ft 105G M
p R
E s 1000 5 u R
E 950 p
5 J
Ft 900 PlCURE 5C LOSS OF FLOW STEAM PRESSURE RETRANOl VS RETIWi02 T J ME ! SECDND*S l RETRAl./01::X RETR'1"02::SGJAI\\E
J N
- l 580 E
T*S60 T
E M
p E
R A
T U 540 R
E F
520 e
0 FIGURE 6C LOSS Of FLOW e
INLET TEMPERATURE RETRAN01 VS RETRAN02 2
3 5
6 7
TJ11E t6'ECONOSl RETRRSC'1:-X RE T R Fi "l Q 2 = S G, 1 AR E B
9 10
p R
E 5
5 u R
J z E
R p
R E
5 s u R
E p
5 J
A 235G 2300 2250 2200 2150 2100 2050 FJCVRE 7C LOSS OF FLOW PRESSURIZER PRESSURE RE'l'RANO 1 VS RE'TRA.N 02 200D;i:::;:;::::::::;::;::;::;:::::;:::;::;:;::;:;:;::=::;:;:;:;::;:;:;;::;:;;::;::;::;:;:;;:::;:::;:;;:;:::;;::;:::;::;::;:;::;:;:;:;;::;::;;:;;;:;::;;::::;:;::::;:;;;::::;:;:;::;:;:::;::::;:;:::;:;::;::;;:;::::;:;:::::;+
0 2
3 4
5 6
1 B
9 10 TJP1E lSECONOSl RETRRNOl =X.
RE1RRN02=5GJARE
------i
FIGURE ec LOSS or FLOY LOOP FLOW RE'TRAN O l VS RETR.AN02 l. 2 1. 1 l.o L
0 0
Q.9 p
r L
o.s 0 w Ci.1 F
R A
C Ci. 6 T
J 0
N o.s 0
f Q.4 N
0 t1 J
0.3 N
A L
0.2
- 0. 1 o.o 0
2 3
4 5
6 7
6 9
10 T J ME 15ECON051 RE1'RAN:J1::X
~E TRANG2 ::SGJF!~.E