ML19316A040
| ML19316A040 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 01/15/1973 |
| From: | BABCOCK & WILCOX CO. |
| To: | |
| Shared Package | |
| ML19316A038 | List: |
| References | |
| NUDOCS 7911210602 | |
| Download: ML19316A040 (65) | |
Text
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- ATTACIDfENT I
_ CORE FLOODING NOZZLE MECHANICAL DESIGN l
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i LIST OF FIGURES 1
Existing Core Flooding Nozzle Sleeve j
2 Oconee I Core Flooding Nozzle Insert 3
Core Flooding Nozzle Af ter Removing Existing Sleeve l
4 Core Flooding Nozzle Weld Preparation Prior to Inserting Modified i
- Insert i
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5 Core Flooding Nozzle Insert Installed in Core Flooding Nozzle 1
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n The core flooding nozzle modification for the Oconee I nuclear plant is basically a variable diameter thermal sleeve which reduces the nozzle opening from 0.72 ft2 to 0.44 ft2 rication, and field installation of the sleeve.This section reviews the design, fab-The existing core flooding nozzle and thermal sleeve are shown in Figure 1.
The existing sleeve will be removed to enable installation of the modified sleeve.
The restrictor is fabricated in two scages as shown va Figure 2.
Because of schedule restraints related to installing this modification at Oconee, it was necessary to use available raterial.
Thus, Type 304 stainless steel pipe was used and weld overlay was deposited to meet _the required 9" I.D.
The pipe and weld overlay were U.T. examined before machining with P.T.
examination af ter final machining.
accordance with ASME Section III.
These examinations were performed in Removal of the existing sleeve is accomplished by grinding the weld buttons which hold it in place, and performing a P.T. examination on the ground areas (Figure 3).
The nozzle is then ready for installing the restrictor.
This will be accomplished by welding and machining the weld buttons and ring as shown in Figure 4.
The restirctor is inserted and a full penetra-tion weld with permanent backing ring is made in accordance with ASME Section III (Figure 5).
A progressive P.T. is performed to insure a qual-ity weld.
The weld buttons center the restrictor.
A drain hole is drilled the bottom of the weld to allow a small flow of water behind the re-at strictor to prevent crud buildup.
The restrictor and attachment veld (Figure 5) are evaluated in accordance l
with ASME Section III.
The significant transients which affect the re-strictor and weld are reactor coolant system heatup and cooldown including the core flooding system periodic test transient and decay heat removal initiation.
All transients are considered as normal operating conditions and are considered in determining thermal stresses and the fatigue usage factor.
The fatigue analysis includes a strength reduction factor of two on the weld per ASME Section III.
The weld has also been designed to with-stand the faulted condition where a differential pressure of up to 2250 poi may occur because of a core flooding line LOCA. A dynamic magnifica-
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tion factor of two was applied to the pressure to account for instantaneous application.
Based on these criteria, the average shear stress in the weld yields a t4afety margin of 1.4.
These assumptions and safety marg'n are i
sufficient to insure the structural integrity of the ndzzle, restrictor, and weld for all operating and faulted conditions.
During the core flooding transient, the maximum Ap across the nozzle is expected to be approximately 200 psi.
This is a factor of greater than 20 less than the design loading assumptions. 'Therefore, it is not consi-dered credible that the restrictor retaining weld would fail during core flooding tank discharge.
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During operation of the decay heat system, the Ap loads on the restrictor are insignificant.
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FIGURE 1 EXISTING CORE FLOODING N0ZZLE SLEEVE s
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~ M V ' v a ...a* ff./b~- - ~ ~ ~.- ~_ 800 Bottom of Active Region 400 0 0 200 400 600 000 1000 1200 1400 1600 1800 2000 Time, s e FIGURE 4-1 CORE PRESSURE VERSUS TIME 2400 %P o 2000 1600 a " 1200
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w 0 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Time, s S 6 0 0 0 m 2 0 0 0 i 1 i i i i E M m I T SU S 0 R 0 E 1 V i R E i W i s O P i E e RO m C i T m 2 4 E R U G I F 0 1 i i i i m i 1 6 2 0 8 4 0 1 0 O 0 0 0 Ea. NGEE 9 FIGURE 4-3 INNER VESSEL FLUID VOLUMES VERSUS TIME 2000 2400 2000 k p 1600 "O Top of Active Region d 1* ' Mixture Volume E 1200 I ~= Liquid Volume 800 Bottom of Active Region ~ 400 0 0 200 400 600 800 1000 1200 1409 1600 1800 2000 Time, s e FIGURE 4-4 VENT VALVE FLOW VERSUS TIME 3200 2500 - 2400 2000 - f1600 0 8 1200 l/ / s00 f \\_/ 400 Lt ws_- 0 200 400 600 000 1000 1200 1400 1600 1800 2000 Tlas t FIGURE 4-5 LEAK FLOW VERSUS TIME 9000 8000 7000 6000 E 5000 4000 %3 3000 2000 1000 0 ~/ 0 200 400 600 800 100h 1200 1400 1600 1800 2000 Time, s e o FIGURE 4-6 WATER HEIGHT IN CORE AND DOWNCOMER VERSUS TIME 36 32 28 7 o 24 ~ o .E. f 20 2 ( 2 5 16 f 0 f owncomer 5 12 - IY ) E 8 Downcomer
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N 3 Core- ,1 l \\ 4 b Core 1 0 l 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Time, s P ~ FIGURE 4-7 FLUID VELOCITIES FROM THE DOWNCOMER TO nic LOWER HEAD DURING CFT INJECTION 6 4 Path 29 m lAr x \\ r / \\ l \\ i / \\ l \\ 0 I I I g -2 / \\ I \\ E l \\ f g = 1 1 / Path 19 It C -4 L"/ f i /
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A ,, - - - -. - =.., / g -6 W 140 220 300 380 460 540 620 700 780 860 Time, s 6 N FIGURE 4-8 AXIAL POWER SHAPE FOR CASE 1 2.0 1.8 1.6 1.4 1.2 g Ax al Peak = 1.786 1'0 E Radial Peak = 1.7157 2 0.8 Axi al Power Sha'pe \\ O.6 - - - Power Di stri bu tion k Used in THETA 0.4 - 0.2 T 0.0 1 2 3 4 5 6 7 8 9 10 Axial Segment - - - - ^ - _.. -,. _. _. _ -. _ = _ _,. _... _. _ _ _ _ 1 FIGURE 4-9 CASE 1, LEVEL 5 - SINK TEMPERATURE VERSUS TIME 1400 1200 i 1000 i j. ,e s00 1 E .S_ 600 T a 400 C + 200 't b. O -200 400 600 800 1000 1200 1400 1600 1800 2000 Time, s e 4 ~ 0 FIGURE 4-10 CASE 1, LEVEL 5 - HEAT TRANSFER COEFFICIENT VERSUS TIME 106 5 10 y c; E' 4 l S 10 E 4 m M L O 3 10 0 m E 102 m 101 l 0 400 800 1200 1600 2000 Time, s I i 9 0 0 0 ~ 2 0 0 8 1 EM I T S 0 U 0 S 1 6 R EV E RU 0 T 0 A 1 4 R E PM ET 0 G 0 2 N 1 I DDAL s C 0 e 0 m 0 i 1 T 5 LEVEL 0 0 8 1 E SAC 0 0 6 1 1 4 0 E I 0 R 4 UG IF 0 0 2 \\ 0 0 0 0 0 0 0 0 0 0 0 0 0 4 2 0 0 0 0 1 4 1 8 6 4 2 w,i3 . ; = 3".a L FIGURE 4-12 CASE 1, LEVEL 9 - SINK TEMPERATURE VERSUS TIME 650 9 600 550 500 E E 450 O ta 400 h 350 -~ 300 0 200 400 600 800 1000 1200 H00 IW M E Time, s FIGURE 4-13 CASE 1, LEVEL 9 - HEAT TRANSFER COEFFICIENT VERSUS TIME 5 10 ~ ~ .104 t "I T E h 103 m I E G I I 0 102 0 t g E N -W 10I 100 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Time, s I FIGURE 4-14 CASE 1, LEVEL 9 - CLADDING TEMPERATURE VERSUS TIME 1400 1200 1000 t. 800 2O g 600 i [ k 400 230 0 0 200 400 600 800 1000 1200 I400 1600 1800 2000 Time, s l ll 0 0 0 2 0 0 8 1 E Df T 0 S 0 U 6 1 S REV ERU 0 0 T 4 A 1 REP M ET 0 0 K 2 N 1 I S 0 s 1 0 0 0 e, L 1 m E i T VE s L 0 1 0 J 8 E SAC 0 0 M 5 6 1 4 ERU 0 G 0 4 I F 002 0 0 0 0 0 0 0 0 0 0 0 0 0 4 1 2 0 8 8 2 0 1 1 7 i 5 ".E~ sG i FIGURE 4-16 CASE 1, LEVEL 10 - HEAT TRANSFER COEFFICIENT VERSUS TIME 105 W m M 4 10 d: e. ms 5 103 m E E 2 [ 10 s N E 101 W e W 100 0 400 800 1200 1600 2000 Time, s FIGURE 4-17 CASE 1, LEVEL 10 - CLADDING TEMPERATURE VERSUS TIME 1200 i000 800 ?.: 5 i 600 mi f i um / 400 / 200 ~- 0 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Time, s FIGURE 4-18 AXIAL POWER SHAPE FOR CASE 2 1.6 1.4 1.2 \\ a 1.0 [ %2 0.8 Axial Peak = 1.533 Radial Peak = 1.665 Axial Power 0.6 Sh ap e - - -- Power Di stri bu-tion used in THETA 0.4 0.2 1 2 3 4 5 6 7 8 9 10 Atlat Segment 6 -_._s a-s FIGURE 4-19 CASE 2, LEVEL 7 - SINK TEMPERATURE VERSUS TIME 650 600 550 i 3 500 t .I 3 458 400 3 350 3 ~ 300 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Time, s i l 1 FIGURE 4-20 CASE 2, LEVEL 7 - HEAT TRANSFER COEFFICIENT VERSUS TIME 105 w h me 4 10 m b e W R 103 m R - r ~ ~ 2 S3 0 102 the \\ E seu ~ I 101 Y = 0 h 10 400 800 1200 1600 200,0 Time, s I FIGURE 4-21 CASE 2 LEVEL 7 - CLADDING TEMPERATURE VERSUS TIME 1200 1000 Yaj 800 .E g 600 G 400 200 0 200 400 600 800 1000 1200 W Time. 5 a FIGURE 4-22 CASE 2, LEVEL 9 - SINK TEMPERATURE VERSUS TI!E 650 600 500 t.: b 5 450 L E: a G 400 350 'A 300 O 200 400 600 800 1000 1200 1400 1600 1800 2000 Time, s FIGURE 4-23 CASE 2, LEVEL 9 - HEAT TRANSFER COEFFICIENT VERSUS TIME 5 10 M m e 4 10 ~ $ 103 = J E -o 5 102 o 5 =
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~ E 101 m W i ~ 100 i e i i 0 400 800 1200 1600 2000 Time, s FIGURE 4-24 CASE 2, LEVEL 9 - CLADDING TEMPERATURE VERSUS TIME 1200 1000 m J 800 600 A f\\ J t 400 200 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Time, s FIGURE 4-25 CASE 2, LEVEL 10 - SINK TElfPEUATURE VERSUS TIFE 650 600 500 d E @ 450 = 3 %a 400 T 350 300 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Time,s FIGURE 4-26 CASE 2, LEVEL 10 - IIEAT TRANSFER COEFFICIENT VERSUS TIME 0 10 m W 4 10 ? L ~ ~ f 103 b E ~ G: 5 2 10 h N g E 101 O e i ~ l 0 10 i 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Time, s i FIGURE 4-27 CASE 2, LEVEL 10 - CLADDING TEMPERATURE VERSUS TIME 1400 1200 1000 t,,- 000 E e s00 L / VJdA 200 0 0 200 400 800 000 1000 1200 I400 1600 1200 2000 Time, s t FIGURE 4-28 AXIAL FONZR SHAPE FOR CASE 3 1.6 1.4 [ i Antal Peak = 1.466 Radial Peak = 1.432 1.2 Axial Power shape F ~-- -- - --- Power Di stri-bution used %g 1.0 in THETA f / 0.8 0.6 ~ l 0.4 e 1 2 3 4 5 6 7 d 9 10 Atlal Segeert g 0 0 0 2 0 0 9 EM I 0 T 0 6 S 1 U S RE V E 0 0 R 4 U 1 TAR E P M E 0 0 T 2 1 KN I S 0 0 s 9 0 1 L e, m E i V T EL w 0 0 3 8 E SAC 0 0 9 6 2 4 E RU 0 G 0 4 I F 0 0 2 I 0 0 0 0 0 0 0 0 0 5 0 5 0 5 0 5 0 6 6 5 5 4 4 3 3 7,:B* .E.* i G FIGURE 4-30 CASE 3, LEVEL 9 - HEAT TRANSFER COEFFICIENT VERSUS TIME 105 I 4 10 o7 \\ ~~ 3 h 10 s W~ Z 2 2 C 3 102 O t c \\ 2 10I ~ i ~ l 100 0 400 800 1200 1600 2000 Time, s FIGURE 4-31 CASE 3, LEVEL 9 CUDDING TEMPERATURE VERSUS TIME I400 1200 1000 Y f 800 = as 800 k - I k f 1 = G 400 200 0 0 100 400 600 800 1000 1200 1400 1600 1800 2000 Time, s FIGURE 4-32 CASE 3, LEVEL 10 - SINK TDIPERATURE VERSUS TIME 1400 1200 1000 800 p B h 800 k Im 400 200 0 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Time. s l l ( l [ l FIGURE 4-33 CASE 3, LEVEL 10 - IIEAT TRANSFER COEFFICIENT VERSUS TIME 105 m D 4 10 M P a 103 5 [ P 5 a S 102 s t N a t E 1 10 = I iOO 0 400 800 1200 1600 2000 Time, s E8 E H E P m o w S w C4w w a a N f w $wa 8 e w z oo e 5 J U E ) a C i 8 O M Aw>w o A / o" m w m< a r 8 5 o I m 1 4 M E o H N 8 m s o 8 E g 8 o a 8 E ~ J 'ainteJadwal Butppel3 pm_-- .am m_eame.a_4m--- w n se- _am. .m_eahw-m---aa- .ma4w, es_.-4.4 s__a__-ma A a a.m__a ATTACHME';f III } i 4 a f f f I I I I I l t I 1 i 4 1 d P h i ) I ,I a i 1 I 4 4 4 i 1 4 l i 4 .I L .m -. ,..-_-,.,,y-,m,,,, y,7,-. m y w.m ,w,7., ,w.., w e-.,,w www wy yr= -,pe-e g k f Previous analyses have shown that a marginal amount of water is maintained in the core following a core flooding tank line break. This is due to a partial degrading of the ECC System as a natural consequence of the acci-dent. In order to improve the safety of the design, a flow limiting insert is to be placed in the core flooding tank nozzle to control the accident. By limiting the violence of the blowdown, less reactor coolant system water will be ejected from the primary system. Thus, more water will be maintained in the core during and af ter blowdown. The acceptability of the insert is dependent on three points. First, it must be shown that it can be built and installed to function as designed. This has been addressed in Attachment 1. Second, it is necessary to show that the insert as designed will produce the desired results. This has been addressed in Attachment II. Finally, it is necessary to show that the insert will not jeopardize the perf orme. ace of the ECC System during other accidents. This is addressed in this attachment. By standard methods of analysis, a i-factor has been determined for the 2 insert. The value of this factor is 0.2 based upon an area of 0.7213 ft and is used to solve for the pressure loss op in the following equation: klW [W_ 3p, 288 pg A where W = flow rate, Lbm/sec p = density, Lbm/f t g = gravitional constant, Lbf e A = Area, ft The k-factor for the coce flooding line resistance used by B&W in the evaluation of LOCA's presented in BAW-10034 was 6.3. This value is typical of all plants of this type. Theproppsedinsertwouldincrease the resistance by only 3%. To show that such an inc ease is acceptable, an analysis of the worst case large break, an 8.5 f t cold leg split, has been carried out for two different k-f actors. The first value, k = 8.3, has an increase (6.3 + 2.0) an order of magnitude higher than the proposed insert. This was chosen before the insert had been designed in order to bound the result. The second value, k = 5.5, is based on an experimental measurement of the line k-factor without the insert, k = 4.8, plus a conservative evaluation of the insert effect, k insert = 0.7. With a more concrete design and a better evaluation of the effect of the insert, we expect the actual line resistance to be k = 4.8, plus k insert = 0.2 or k = 5.0. III-l t The results of the two different k-factors are shown in Figures 1 and 2. Figure 1 shows the core flooding tank injection rate for two tanks. Fig-ure 2 shows the resulting peak cladding temperatures. Both temperatures are acceptable and are within the AEC Interim Acceptance Criteria. These results show that there is no adverse effect of the insert for large breaks. For small breaks, the core flooding tanks provide water at a very slow Thus, the important parameter in the core flooding tank system is its rate. pressure volume relationship and not line resistance. An increase of only 3% in CFT line resistance would have no effect on small breaks. I III-2 a ~ FTCURE 1 CORE FLOODING TANK INJECTION RATE DURING AN 8.5 FT COLD LEG LOCA FOR VARIOUS FLOW RESISTANCES 4 8000 1 7000 f 4, l \\. k = 5.5 _.-- Experimental + insert 6000 rr y/ \\ 's t i = 8.3 _ _ _ _ Oesign 3,,, f \\ + Orif. ice g j <y, 4000 m \\ f \\ w ws\\ N I %\\ E k 3000 s 2000 1000 0 O 4 8 12 16 20 24 28 32 36 40 Time s FIGURE 2 HOT SPOT CLADDING TEMPERATURE DURING AN 8.5 FT COLD LEG LOCA FOR VARIOUS FLOW RESISTANCES IN THE CORE FLOOD TANK LINE e 2600 2400 2200 a -~~~~-~~____ ' ' ~ ' ' *. g '~ s~3 ( ~ o' f [ N 3300 s e f N 1600 1 I 5* 1I10 0 K = 5,5 ( 2116*F) ? 4;; I200 G - - _ _ _ K = 8. 3 ( 216ttop) 1000 800 600 0 10 20 30 40 50 60 70 1 T im e, s l