ML20235J637
| ML20235J637 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 07/08/1987 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| Shared Package | |
| ML20235J640 | List: |
| References | |
| NUDOCS 8707150673 | |
| Download: ML20235J637 (24) | |
Text
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r TENNESSEE VALLEY AUTHORITY CH ATTANOOGA. TENNESSEE 374o1 SN 157B Lookout place JUL 0 81987 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 Gentlemen:
In the Matter of
)
Docket Nos. 50-327 Tennessee Valley Authority
)
50-328 SEQUOYAH NUCLEAR PLANT (SQN) - LEAKAGE OF SPRAY WATER BEHIND THE CRANE WALL FOLLOWING A POSTULATED DESIGN BASIS ACCIDENT (DBA)
On September 18, 1986, a condition was identified at SQN whereby, during operation of the containment and residual heat removal (RHR) spray systems following a DBA, spray water collecting on the operating deck floor could be drained directly into areas outside the crane wall through the opening fer containment air return fan A-A.
Initially, the concern was that this drainage would result in undesirable low water levels above the sump. Upon further investigation, the concern shif ted from the low water levels in the sump to the potential flooding of containment air return fan A-A, thus making that fan inoperable. Applying the single failure criteria and assuming containment air return fan B-B fails, the flooding of fan A-A would render both fans inoperable following a DBA.
This condition has been evaluated, reported to NRC in Licensee Event Report (LER) 50-327/87003 and plant modifications have been designed and implemented to preclude the flooding of containment air return fan A-A.
A summary description of the condition, evaluation of the condition, modifications to correct the condition, and the status of the impleinentation of those modifications are provided in enclosure 1.
A copy of the report evaluating hydraulic behavior of a scale model of the SQN sump with low water levels is given in enclosure 2.
A letter from the vendor evaluating containment air return fan performance with entrained water in the air is provided in enclosure 3.
A commitment to amend the text of the SQN Final Safety' Analysis Report (FSAR) to reflect the modifications described in enclosure 1 is given in enclosure 4.
6707150673 B70708 ADOCK0500g7 PDR S
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'*' U.S. Nuclear Regulatory Commission JUL 0 81967 Please direct. questions concernin6 this matter to Rusty Proffitt at (615) 870-7461.
Very truly yours, TENNESSEE VALLEY AUTHORITY
/
R.
ridley, D* rector Nuclear Safet and Licensing cc (Enclosures):
Mr. G. G. Zech, Assistant Director for Inspection Programs Office of Special Projects U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 Mr. J. A. Zwolinski, Assistant Director for Projects Division of TVA Projects
-Office of Special Projects U.S. Nuclear Regulatory Commission 4350 East West Highway EWW 322 Bethesda, Maryland 20814 Sequoyah Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry Road Soddy Daisy, Tennessee 37379 4
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ENCLOSURE 1 1
SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 1
I DOCKET NOS. 50-327 AND 50-328 i
SUMMARY
DESCRIPfl0N
)
0F SPRAY WATER LEAKAGE BEHIND THE CRANE WALL AT SQN
ENCLOSURE 1 SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 WATER LEAKACE BEHIND CRANE WALL BECAUSE OF ACTUATION OF THE CONTAINMENT AND RESIDUAL HEAT REMOVAL (RHR) SPRAY SYSTEMS INTRODUCTION' Immediately following initiation of a postulated Design Basis Accident (DBA),
both the Emergency Core Cooling System (ECCS) and the Containment Spray System
-(CSS) are aligned to take suction from the Refueling Water Storage Tank (RWST). The ECCS supplies water to the Reactor Coolant System (RCS) to cool
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l the core, while the CSS generates a spray inside containment to assist in mitigating the temperature and pressure transient resulting from the postulated DBA.
Coolant that escapes through the breach in the RCS and the containment spray flow is collected in the containment sump. Approximately 30 minutes after initiation of the postulated DBA, the ECCS and'the CSS are realigned to operate in the recirculation mode by drawing suction from the containment sump for the duration of the event.
A crane wall partitions the containment into an inner cylindrical region and an outer annular region. The containment sump is located within the inner cylindrical region.
During operation in the recirculation mode following a postulated DBA, low water levels in the containment sump could provide for the generation of local fluid vortices near the sump suction inlet. These vortices, if of sufficient strength, could potentially cause pump cavitation by entraining air bubbles in the pumped fluid. To preclude this occurrence, the crane wall is sealed watertight to an elevation of 13.2 feet above the containment sump.
Therefore, for a DBA, a minimum elevation of 13.2 feet of water above the containment sump is provided for when the ECCS is in the recirculation mode, with any excess being able to leak outside the crane wall. Using a scale model test, the 13.2 feet of water has been shown to be adequate to preclude generation of local fluid vortices near the containment sump suction.
The operating deck, located above the containment sump, is designed to collect falling spray water and divert it to the inner crane wall region through the refueling canal / reactor cavity area.
On September 18, 1986, a condition was identified whereby, during containment spray operation, spray water could bypass its intended flow path to the inner crane wall region by draining directly to areas outside the crane wall through an opening for the containment air return fan designated as fan A-A.
Subsequently, the equipment access hatch and personnel access door trenches were also identified as potential inner crane wall bypass leakage paths. These trenches would also direct spray water through the opening for containment air return fan A-A.
Upon further consideration, it was noted that the operation of the two containment air return fans could divert spray water entrained in containment atmosphere by exhausting the mixture to accumulator rooms located outside the crane wall. Although expected to be substantially smaller than the draining of spray water from the operating deck through fan A-A, long-term operation of the fans could have a similar effect on water level in the sump.
Also, the
1
. two-phase mixture will place additional loads on the fans and motors that have
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not been previously considered. A significant flow of water through containment air return fan A-A could result in the failure of that fan.
If a single failure is postulated, the remaining containment air return fan, fan B-B, would also be inoperable.
This would result in total loss of containment air return f an capability.
The preceding conditions have been evaluated and corrective actions to prevent those conditions from occurring have been identified and implemented. A description of the conditions, summary of the evaluation performed, and
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details of the corrective actions follow.
l l
CONDITION DESCRIPTION The crane wall subtends a 300 -arc within the steel containment vessel above 0
the operating deck, figure 1.
There are two containment air return fans, designated fan A-A and fan B-B, located between the crane wall and the steel 0
containment vessel within the 60 -are not subtended by the crane wall. The intake for fan B-B is elevated above the operating deck floor, and the intake for fan A-A is located below the operating deck floor, figure 2.
There is a two-inch high curb surrounding the refueling canal. Thus, as containment l
i spray water runoff collects on the operating deck floor, the water will tend to drain through several uncurbed areas about the pit containing fan A-A until the water level on the floor reaches an elevation of two inches above the floor. Above this two-inch elevation, the containment spray water will drain both through fan A-A and into the refueling canal. The drainage into the refueling canal is directed to the containment sump.
Drainage through fan A-A is directed outside the crane wall and is, therefore, diverted from containment sump, until the 13.2-foot elevation level identified in the SQN Final Safety Analysis Report (FSAR) is reached.
Similarly, a buildup of containment spray water on the operating deck floor would result in flow into uncurbed trenches below the equipment access hatch and the personnel access door. There is a seal between the containment and operating deck that is located in these trenches. This seal is expected to remain intact should water fill the trenches. With the seal intact, water flowing in these trenches would drain to regions outside the crane wall through the inlet of containment air return fan A-A.
Thus, this drain flow would also be diverted from the containment sump, until the 13.2-foot elevation level identified in the FSAR is reached.
In addition, the operation of the fans themselves would cause containment spray water to be ducted to regions behind the crane wall.
Containment spray operation causes highly turbulent airflow.
This turbulent airflow may result in entrained water droplets from containment or residual heat removal (RHR) spray being drawn through both air return fans. As was the case with drainage through fan A-A, the entrained water is ducted to regions behind the crane wall and is therefore also diverted from the containment sump, until the 13.2-foot elevation level identified in the FSAR is reached.
The preceding flow and drain paths were evaluated to determine possible impact on both the water level in the sump and the operability of containment air return fans. A summary of that evaluation follows.
1
. CONDITION EVALUATION The total volume of water inside containment but outside of the RCS following a DBA has been calculated. Assuming that the design works as intended (that is, no runoff flow follows the flow paths identified in the preceding section) and using minimum actual ice weights taken from surveillance testing, the distribution of water inside containment following a DBA has also been calculated. The results of these calculations are summarized in table 1.
However, the flow paths identified in the preceding section can divert additional containment spray water to areas outside the crane wall, thus decreasing the water level inside the crane wall.
The following evaluation of these flow paths was made.
The design of the operating deck is supposed to provide for containment spray runoff to be directed into the refueling canal and from there to the containment sump.
There is, however, a two-inch curb on the operating deck about the edge of the refueling canal. Thus, containment spray water runoff must collect in a pool on the operating deck to a depth of more than two inches before runoff into the refueling canal will occur.
There are trenches in the operating deck floor below the equipment eccess hatch and the personnel access door that run to the opening for containment air return fan A-A.
At the time the evaluation was performed, there were no curbs between the trenches and the operating deck. Thus, as spray water falling on the operating deck would begin to form a pool, water would flow into these trenches, pass through a raceway, and then drain through the opening for containment air return fan A-A and into accumulator room 3.
Recalling that fan A-A is located at an elevation below the operating deck, spray water collecting on the operating deck would also flow directly into the opening fer fan A-A and drain into accumulator room 3.
The operation of containment air return fans A-A and B-B will also suck water entrained in the containment atmosphere through the fan openings and into accumulator-rooms 3 and 4. respectively. Containment spray is designed to direct spray inside the crane wall only. However, for the purposes of the current evaluation, a homogeneous distribution of spray throughout the total air volume above the operating deck, including the region outside the crane wall, was conservatively assumed. Using this assumption, the total rate of entrained water that would pass through the two fans has been evaluated to be 140 gal / min, or 70 gal / min per fan.
The containment air return fans have been evaluated by the vendor and found to be capable of performing their intended function with this amount of entrained water in the containment air. A copy of the letter from the vendor documenting that evaluation is given in enclosure 2.
Accumulator rooms 3 and 4 are located outside of the crane wall.
Thus, spray water that would pass through the containment air return f an openings would be diverted from the containment sump.
Assuming both trains of containment spray were in operation, the rate at which water will be diverted to behind the crane wall was calculated to be about 6,000 gal / min. The water level outside
. the crane wall will rise to about 16.0 feet (elevation 695.8) and drop to 7.8 I
feet (elevation 687.6) inside the crane wall. At this point, water spillover from outside to inside the crane wall will equal the rate of water loss to behind the crane wall from the operating deck. At the conditions evaluated, it is estimated that this equilibrium water level condition will be attained in about 20 minutes after initiation of the postulated DBA.
Net positive suction head (NPSH) requirements of the RHR and containment spray pumps were evaluated and found to be well below the levels available with 7.8 feet of water above the sump.
The FSAR states a water level cf 13.2 feet will be available in the sump at the time of switchover from the RWST to recirculation from the sump.
Containment and, had it been initiated, RHR spray may be terminated when containment pressure drops to 2.81 psig. Assuming one train operation of both the containment and RHR spray systems, the containment pressure is calculated to drop to the 2.81-psig level seven days after initiation cf the postulated DBA. With two trains of containment spray operating, it is estimated that the 2.81-psig pressure level will be reached in four to five days. Thus, elevated containment pressures preclude terminating spray operation as a means of preserving water level inside the crane wall at the 13.2-foot elevation level identified in the FSAR.
Using a scale model of the SQN containment sump, the hydraulic behavior of the sump with low water levels was investigated.
Slight surface swirling of water was observed in the region of the sump suction with a water depth equivalent to eight feet above the sump. Using data from other tests, water levels as low as 3.2 feet above the sump have been evaluated and determined not to adversely affect long-term ECCS operation.
Although more pronounced local swirling may be expected to occur at the lower water levels, the data evaluated indicates that generation of vortices of sufficient strength to result in pump cavitation would not occur. A copy of the evaluation report is given in enclosure 3.
In summary, for spray operation following a postulated DBA, calculations have been performed that predict as much as about 6,000 gal / min of spray water can be diverted.from the operating deck floor to behind the crane wall by the flow paths identified in the preceding section. At this rate of flow, the water level inside the crane wall will stabilize at a height of 7.8 feet above the sump within approximately 20 minutes af ter initiation of a postulated DBA.
This height is 5.4 feet below the water level identified in the FSAR.
Using a scale model of the SQN sump design and other supporting test data, water levels equivalent to as low as 3.2 feet above the sump were evaluated.
At the lower water levels, local fluid swirling was noted. Although such swirling is indicative of vortex development, the swirling observed in the tests would not result in pump cavitation. Also, given the conservative nature of the calculations performed to estimate the water level inside the crane wall, the actual water level in that region is expected to be higher than the 7.8-foot elevation that was calculated. Furthermore, testing has demonstrated that the entrainment and transport of air bubbles through a 7.8-foot elevation to the pump suction, where ingestion into the recirculation system could result in cavitation and pump degradation, will not occur. Also, NPSH requirements will be adequately satisfied with 7.8 feet of water above the sump.
e However, the large volume of water that could drain from the operating deck through fan A-A could cause that fan to become flooded.
Once flooded, fan A-A would be inoperable. Using the single-failure criteria to postulate fan B-B to fail, the flooding of fan A-A would render both fans inoperable. This scenario would adversely affect the performance of the ice condenser during a hypothetical DBA.
Thus, a method was developed for eliminating or restricting drainage of spray water collected on the operating deck into f an A-A.
- Also, to maintain the water level above the samp as close as possible to the 13.2-foot level given in the FSAR, a method was also developed for redirecting entrained spray water collected in accumulator rooms 3 and 4 to inside the crane wall.
MODIFICATIONS Two modifications to the flow paths identified above have been devrpoped. A description of those modifications follows.
Curbs on Operating Deck Curbs will be installed around the equipment access hatch, the personnel access door, and the pit containing containment air return fan A-A.
These curbs, or " kick-plates," will be either 4.5 or 5.0 inches high, or either 2.5 or 3.0 inches higher than the curb surrounding the refueling canal. The increased height of the new curbs will cause spray water collected on the operating deck floor to spill into the refueling canal rather than drain through the trenches running about the equipment hatch and the personnel access hatch and through containment air return fan A-A.
The location of the curbs is shown schematically in figure 3.
The placement of the curbs on the operating deck floor will eliminate concerns over water runoff from the operating deck through containment air return fan A-A.
The water loss rate from the operating deck floor to behind the crane wall will be reduced from 6,000 gal / min to 140 gal / min.
The 140 gal / min of water is entrained spray sucked through the containment air return fans. A letter from the fan manufacturer confirming that there is no detrimental effect on fan performance because of this amount of water entrained in the air passing through the fan is provided in enclosure 2.
The water level would stabilize at 7.8 feet above the sump. This water level j
is within the range of levels that were evaluated and determined not to result l
in potential ECCS performance degradation.
However, a reduction in ice bed weight is being considered for SQN.
Reduction in ice bed weights would
/
further reduce the water levels below the 7.8-foot level. Thus, additional modifications were undertaken to return entrnined spray water from accumulator rooms 3 and 4 to the containment sump.
Drains in Accumulator Rooms Containment air return fans A-A and B-B exhaust into accumulator rooms 3 and 4,
respectively.
Spray water entrained in the airflow through the fans will be deentrained into the accumulator rooms as the air velocity decreases.
Modifications will be made in the accumulator rooms to trap the deentrained spray water and drain that water back inside the crane wall.
. The modifications that will be implemented ara:
Install 5.0-inch curbs in each room as rcquired.
I Seal penetrations through the accumulator room floors as necessary.
]
Using four-inch piping, construct a drain that runs from each accumulator room floor to inside the crane wall as shown in figure 5.
- Install orifices on the existing floor drains to limit total flow through them to less than five gal / min.
This will provide for essentially all entrained spray water that may be carried into the accumulator rooms by operation of the containment air return fans to be returned to inside the crane wall. A schematic of the accumulator room drains is shown in figure 5.
STATUS OF MODIFICATIONS The status of the two sets of modifications described in the preceding section is as follows:
All design and engineering for curbs and drains are complete on unit 2.
- Field modifications associated with.the curbs and drains are complete on unit 2.
Calculations supporting design and engineering of the curbs and drains have been checked and verified for unit 2.
Drawings have been updated to reflect the subject modifications for unit 2.
Thus, all efforts associated with the curb and drain modifications have been completed on. unit 2.
All efforts associated with this modification will be complete on unit 1 before restart.
The containment air return fan motors have been evaluated by the vendor and determined to be capable of perfonning their intended function with a uniform distribution of spray water in the containment atmosphere above the operating deck. The electrical system is cur' rent.ly being evaluated to determine if it is capable of handling the increased loading that would result from such operation. The evaluation is expected to be completed by July 15, 1987.
SUMHARY Conditions have been identified that, following a postulated DBA, could provide for the diversion of containment spray water from the operating dock floor to outside the crane wall. The water level outside the crane wall would rise to a height of 16.0 feet, and the water level inside the crane wall would fall to 7.8 feet. Water levels would then stabilize; the flow diverted from the operating dock to behind the crane wall would equal the leakage from
_a
. outside to inside the crane wall. These water levels were evaluated using minimum actual ice weights taken from surveillance testing.
An evaluation of scale model testing has shown that, at water levels above the sump of 3.2 feet or greater, strong vortex generation does not occur. Mild vortices that may be generated as water levels approach the 3.2-foot elevation are not expected to entrain air bubbles that, should they be ingested into the ECCS, would cause pump cavitation that could result in degradation of long-term ECCS
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performance.
1 The draining of spray rater from the operating deck through containment air return fan A-A, however, could result in the flooding of that fan and thereby render it inoperable.
If, by use of the single-failure criteria, containment air return fan B-B was assumed to fail, both containment air return fans would be inoperable; and the ability of the ice condenser to mitigate the containment pressure and temperature transient would be reduced.
- Thus, modifications to preclude the flooding of containment air return fan A-A were developed. Curbs or " kick-plates" will be installed about the containment air return f an A-A and about the trenchas under both the equipment hatch and the personnel access door. These curbs, being between 2.5-and 3.0-inches higher than the curbs located around the refutling canal, will cause spray water runoff to flow into the sunp through the refueling canal.
Also, undesired drainage of entrained spray water collected in accumulator rooms 3 and 4 will be restricted by installation of curbs in those rooms, sealing possible leakage paths where practical, and the placement of flow limiting orifices in drains to the waste disposal system. Also, drains will be installed from accumulator rooms 3 and 4 to inside crane wall to provide for spray entrained in the airflow to be returned to the sump region.
These modifications will provide for maintaining an acceptable water level in both the containment sump and outside the crane wall during operation of containment and RHR spray.
Design and engineering work for the curb and drain modifications has been completed, and the hardware installed in the plant.
Supporting calculations have been documented, and changes to affected drawings have been made and checked. The fans and motors have been evaluated by the respective vendors and determined to be able to perform their intended functions under the conservative assumption of a homogeneous distribution of the spray water in the containment atmosphere above the operating deck. Also, the electrical systems in accumulator room 3 and 4 have been evaluated to ensure that the water, entrained in the spray, does not affect the environmental qualifications of the electrical systems. To complete closure of the issue of spray leakage outside the crane wall and its effect on the operability of the containment air return fans folicwing a postulated DBA, the adequacy of the electrical system to handle the increased loading that would result from such operation is being evaluated.
3 Table 1 ESTIMATED WATER LEVELS INSIDE CONTAINMENT FOLLOWING A POSTULATED DESIGN BASIS ACCIDENT Water Resulting Available Elevation Location (r,al)
(ft)
)
)
Inside Crane Wall 357,000 13.2 Outside Crane Wall 175,400 7.8 Reactor Vessel Cavity 115,000 Total Volume of Water 647,000
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ENCLOSURE 2 SEQUOYAH NUCLEAR PLANT (SQN) UNITS 1 AND 2 DOCKET WOS. 50-327 AND 50-328 REPORT X-1178
" REPORT OF WATER FLOWING THROUGH A JOY FAN AT TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT" l
J l
l JOY MANUFACTURING COMPANY NEW PHILADELPHIA DIVISION
~
338 SOUTH BROADWAY P. O. BOX 5000 e ~
NEW PHILADELPHIA, OHIO 44663 Phone: (216) 339-1111 Telefax: (216) 339-8210 Telex: 098 3413 May 15, 1987 Tennessee Valley Authority Sequoyah Nuclear Plant P.O. Box 2000 Soddy Daisy, TN 37379 Attention:
Mr. Jim Warren Subject
- SEQUOYAH NUCLEAR PLANT ANALYSIS DUE TO WATER FLOW TilROUGH FAN.
Reference:
A) TVA Letter Dated Feb. 5,1987 B) TVA P.O. No. NR-74095A
Enclosure:
Analysis Report X-1178 Gentlemen:
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Enclosed is the analysis report on the Joy Fan which will endure the accident
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condition described in reference (A). Also attached with this report is a letter from Reliance Electric.
If you should need any more information, please do not hesitate to call.
Sincerely, JOY MANUFACTURING COMPANY 10.A.177a<x-W.A. Mathias Contract Engineer New Philadelphia Division WAM/vw j
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/
o REPORT NO.
I-1178 DATE May 14, 1987 e
i JOY M ANOFACTURING CO.
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N E W :P.H I L A D E L P H I A. O H I O
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REPORT OF WATER FLOWING i
THROUGH A JOY FAN AT TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT i
thias/ M A M d W.A.
M PEPARED BY T.A. Bisseet/ f g.,, g CHECKED BY Dr.
J.A.
Murph
[*
1 APPROVED BY
<p REVISIONS DATE PAGES AFFECTED REMARKS eei gu 4
4
I 3
OY MANUFACTURING CO.
PAGE a
REPORT NO.
W.A.
Mathias NEW PHILADELPHIA, OHIO PREPARED Bf T.A.
Bissett CHECKED BY DATE May 14, 1987 INTRODUCTION:
The Tennessee Valley Authority has requested JOY Manufacturing Company to analyze the effect of water flowing through a JOY fan during an accident condition at Sequoyah Nuclear Plant.
The accident and conditions are described below 0
I.
Time
=
Accident starts.
10 minutes II.
Time
=
a)
Fans s r. a r t.
b)
Water entrained through fans = 125 gpm.
105* F.
c)
Air and water temperature
=
50 minutes III.
Time
=
Air and water temperature increases to 160*
F.
and remains constant for 5.6 days and then decays to 100* F.
at 30 days.
10 to 20 days IV.
Time
=
Containment spray is shut off at'the earliest time of 10 days.
It is assumed containment spray is terminated no later than 20 days.
100 days V.
Time
=
Fans stop.
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R ace 2
g 3
JOY MANUFACTURING CO.
X-Il78 REPORT NO.
- ^- Mathias i
NEW PHILADELPHIA, OHIO PREPARED BY T.A.
Bissett
(*J1ECMED SY DA315 MaY L4, 1987 u
FAN DATA Fan Model:
45-26-1200 (Steel Rotor)
Serial No.:
GF-16318 and GF-16317 Motor No.:
6002&7.1 50 HP 460/3/60 Insulation Class RN TVA has also asked what effect would there be on the fan units if the water flow was increased to 150, 200. and 300 gpn.
Calculations:
Brake horsepower calculation will be based on tha fan operating at the accident density of 0.098 lbm/ft3 This density value was defined in the original contract.
The effect
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of water flowing through the fan will be evaluated on a msss flow ratio.
Case 1 40,000 CFM @ 5.53" TP @.098 lbm/ft3 Fan Duty:
Water Flow Race:
125 g/ min 40,000 CFM x.075 #/ft$ = 3000 #/ min of air 1000 #/ min of water 125 gpm x 8#/ gal
=
TOTAL MASS 4000 #/ min Calculate BHP of Jan operating at.098 lbm/ft3; fan. total efficiency = 76%.
CFM x total pressure 40,000 x 5.53 BHP
=
6356 x
EFF 6356 x
.76 g
46 BHP
=
Now, ratio the BHP by the total mass flow divided
)
by the air mass flow.
This will be a conservative-1 method of calculating BHP due to. water flowing
]
through the fan.
J 1
0
..p.
9 f
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.Y' MANUFACTURING CO.
PAGE 3-o 3
R E P C P.T N o.
v ii,9 NEW PHILADELPHIA, OHIO PREPARED SY W. A. Mathias CHECKED SY T.A.
Bissetc l
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OATE May 14, 1987
'+
=
3000 r/ min 61.3 hp with 125 g/ min BHP
=
Calculate the f.< H P for the other flows using the same procedure.
=
=
Case 4 300 gpm BHP
- 82. 8 HP-
=
CONCLUSIONS:
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Attached to this report is a letter from Reliance Electric Company stating this motor will be able to operate up.co 75 horsepower with 4000 ft/ min air velocity.
With this information, the maximum water flow through the fan is 200. gal / min.
Any amount over this will increase the BHP over the 75 horsepower limit.
The fan will operate through one (1) accident condition as long as the 200 gal / min is not exceeded, however, there will be considerable wear to the fan rotor.
After one (1) accident, the, fan (motor) unit must be replaced.
a t
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Attachment to Report X-1178 RELIANCE ELECTRIC S TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT POSTULATE DESIGN BASIS EVENT ON RELIANCE ELECTRIC MOTOR X-328203 The motor X-328203 can survive the Sequoyah Nuclear Power Plant event described in TVA's letter of 2/5/87.
The motor will ' be able to operate up to 75 horsepower with 4000 feet / min. air velocity with balanced 460 volts applied at the motor t.erminals.
This event can only be endured once by the motor and only the thermal life capabilities of the motor have been taken into account.
The thermal l'ife of the motor during normal service ;onditions coupled with the TVA Sequoyah Nuclear Power Plant event scenario will use up the majority of the life of the motor when operated with the overload conditions.
It may be beneficial to consider a custom motor design specifically for the new postulated event.
A new motor design would not then be need to function.in the marginal operational zone of the motor design.
. Reliance Electric feels that there is only marginal data available for operation of mo t o r s'. i n this type of overload conditions during an' accident scenario, therefore additional type
. testing is recommended.
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Report Prepaired By:
4< M y
EfY d Y Date:
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ENCLOSURE 3
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SEQUOYAll NUCLEAR PLANT (SQN) UNITS 1 AND 2 l.
DOCKET NOS. 50-327 AND 50-328 1 ;;;
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REPORT NUMBER WR28-2-45-130 l
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" HYDRAULIC PERFORMANCE OF THE SEQUOYAH RHR SUMP i
AT REDUCED DISCHARGE AND WATER LEVEL" l
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