ML17303A797
| ML17303A797 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 02/25/1988 |
| From: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| References | |
| 161-00826-EEVB, 161-826-EEVB, TAC-67346, NUDOCS 8803080276 | |
| Download: ML17303A797 (93) | |
Text
REGULA1 Y INFORMATION DISTRIBUTIOC' SYSTEM (RIDS)
ACCESSION NBR:8803080276 DOC. DATE: 88/02/25 NOTARIZED:
NO DOCKET FACIL:STN-50-528 Palo Verde Nuclear Stationi Unit ii Arizona Publi 05000528 AUTH. NAME AUTHOR AFFILIATION VANBRUNTiE. E.
Arizona Nuclear Power ProJect (formerly Arizona Public Serv RECIP. NAME RECIPIENT AFFILIATION MARTINiJ. B.
Region Si Ofc of the Director
SUBJECT:
Forwards response to RJ Pate request for justification for continued operation of Unit 1 4 inability of Contr'ol Element Assembly 56 to reliably drop during testing. Addi info solicited by C-E 5 fol I oUJed.
DISTRIBUTION CODE:
IE22D COPIES RECEIVED: LTR ENCL
(
SIZE:
TITLE:
- 50. 73 Li,censee Event Report (LER)i Incident Rpti etc.
NOTES: Standardized plant.
O5OOO528 RECIPIENT ID CODE/NAME PD5 LA LICITRAiE INTERNAL:
ACRS MICHELSON AEOD/DOA AEOD/DSP/ROAB ARM/DCTS/DAB NRR/DEST/ADS7E4 NRR/DEST/ESB 8D NRR/DEST/MEBVH3 NRR/DEST/PSBSD1 CARR/DEST/SGB 8D
'RR/DLPG/G*B10A NRR/DREP/RAB10A N~
= ~/SIB'PAi REG 02 RES/DE/EIB RGN5 FILE 01 EXTERNAL:
EQSQ GROH M
H ST LOBBY NARD NRC PDR NSI C MAYSi Q COPIES LTTR ENCL 1
1 1
1 1
1 1
1 1
f 1
0.
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 5
5 1
1 1
1 1
1 RECIPIENT ID CODE/NAME PD5 PD DAVISi M ACRS MOELLER AEOD/DSP/NAS AEOD/DSP/TPAB DEDRO NRR/DEST/CEBSH7 NRR/DEST/ICSB7A NRR/DEST/MTB 9H NRR/DEST/RSB 8E NRR/DLPG/HFB10D NRR/DOEA/EAB11E NRR/DREP /RPB 10A NRR/PMAS/ILRB12 RES TELFORDi J RES/DRPS DIR FORD BLDG HOYi A LPDR NSIC HARRIS> J COPIES LTTR ENCL 1
1 1
1 2
2 f
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
2 2
1 1
1 1
1 NOTES:
1 1
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 48 ENCL 47
Arizona Nuclear Power Project P<.-r'I~I <<>
P.O. BOX S2034
~
PHOENIX, ARIZONA85072-2q+
I"(gal Fpg gb February 2
88 ional Administrator 161-00826-EEVB/JRP Mr. John B. Martin, Reg Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission, Region V 1450 Maria Lane, Suite 210 Walnut Creek, CA 94596-5368
Dear Mr. Martin:
Subject:
Palo Verde Nuclear Generating Station (PVNGS)
Unit 1 Justification for Continued Operation Inability of CEA 56 to Drop File: 88-A-056-026 This letter is in response to a request from Mr. R. J.
- Pate, of your staff, to provide Justification for Continued Operation of Unit 1 in light of the recent inability of Control Element Assembly (CEA)
Number 56 to reliably drop during testing prior to initial criticality after the first refueling outage.
Since then, ANPP has been gathering and analyzing information pertaining to this event.
In addition to the formation of an in-house review group, Combustion Engineering (CE) was included in the investigation and their recommendations were solicited and followed.
Attachment A will provide the following information for your review:
I. Event Description, II. Event Investigation, III.
Event Evaluation and IV.
Conclusion/Corrective Action.
Attachment B
provides the list of figures.
Based on the information and
. material presented
- herewith, the continued operation of PVNGS Unit 1 presents no undue risk to the public health and safety.
Very truly your E. E. Van Brunt, Jr.
Executive Vice President Project Director EEVB/JRP Attachments cc:
O.
M.
De Michele (all w/attachments)
J.
G. Haynes G.
W. Knighton E. A. Licitra T. J. Polich R. J.
Pate 88030802 76 Og000528 880 pDR ADOCH, 0 pDR
7
ATTACHMENT A EVENT DESCRIPTION On January 22,
- 1988, Unit 1 was in Mode 3 at normal operating pressure and temperature.
The CEA Drop-Time test was in progress.
During the testing of CEA 56, the CEA did not drop when its
. individual power supply breaker was opened.
The Reactor Trip Switch Gear (RTSG) was then opened to assure power was removed to the CEA and that it was not an individual breaker fault.
The CEA still did not drop into the core.
After moving the CEA up and down through several cycles (referred to as CEA-"exercising"), the operators were able to insert the CEA to the bottom of the core using the normal Control Element Drive Mechanism (CEDM).
CEA-exercising was continued until the CEA would drop freely to the bottom of the core.
The CEA drop time
'was within the acceptance criteria established by Technical Specifications and.was consistent with the other CEAs.
The CEA was then left at the bottom of the core in order to
,allow completion of drop-time testing on other CEAs.
All other CEAs passed the surveillance test.
The following day testing was resumed on CEA 56 since the cause of the initial binding had not been determined.
Electrical testing of the CEDM coils indicated that there was either a
binding problem somewhere along the
- CEA, or the CEA extension shaft, or the CEDM grippers failed in such a way as to "lock" the grippers on to the extension shaft creating a
rachet effect (the CEA could be withdrawn but not reliably inserted).
Coincident with this event it became necessary to cool the plant down to Mode 5
in order to repair a leak in an RCS auxiliary piping system.
It was decided that further testing would be performed after entering Mode 5.
EVENT INVESTIGATION After discovery of the problem with CEA 56, plant management after consultation with ANPP Senior Project Management, formed an on-site task force review group.
This group was made up of Engineering Evaluations Department.
personnel, Unit 1
Plant Manager, Unit 1 Work Control and CE.
They were tasked with being the focal point for organizing, coordinating, evaluating and directing the trouble shooting and inspection regarding CEA 56.
CE provided inspection, evaluation, direction and assistance during the investigation and recovery.
Subsequent testing of CEA 56 while in Mode 5 consisted of pulling it up 10 inches and then inserting back into the core.
Page 1
0
The CEA moved freely up 10 inches, but could not be inserted nor dropped to the bottom of the core.
The CEA was then pulled to 30 inches'n a
stepwise fashion.
The CEA moved freely out of the core but could not be returned to the bottom of the core.
The CEA was left at the 30 inch level until further evaluations could be made.
Following the cooldown, further testing of the CEDM coil traces verified that the CEDM was performing, electrically, as designed.
The decision was then made to proceed with removal of the CEDM Upper Pressure Housing in order to determine if there was mechanical interference between the extension shaft and the motor guide tube.
Upon completion of this effort no indication of mechanical interference was found.
The CEDM was removed with
" no evidence of binding.
A horoscope examination was performed on the accessible portions of CEA 56 in the Upper Guide Structure (UGS) through the opening of the pulled CEDM.
The boroscope examination allowed inspection of the extension shaft down to the top of the UGS upper support plate, the
- spider, and the extension shaft spider joint.
No evidence of mechanical interference or CEA damage was found using this technique.
Subsequent to the horoscope examination, an attempt to exercise the CEA was made (with the CEDM removed).
This was done utilizing an overhead hoist with a
dynometer installed to measure the lift resistance.
The CEA was initially lifted at a tensile load of approximately 480 lb
, then moved freely upward with the dynometer indicating only tke hanging weight of the CEA (approximately 280lbs).
The lifting force was removed and the CEA did not move downward under its own weight.
An additional 75 lb load was added to the CEA per CE's recommendation.
This effort was not successful and the CEA remained at 32 inches withdrawn.
To continue the investigation, it was necessary to remove the reactor vessel head to gain access to the inner portions of the UGS.
The reactor vessel head was removed and stored on its support stand.
A preliminary inspection.
was then performed using binoculars to determine if CEA 56 was in any way. oriented differently than the other CEAs.
It appeared to be oriented correctly with respect to the others.
Through the use of special
- cameras, an inspection of CEA 56 was performed looking at the extension
- shaft, the extension shaft/spider
This examination determined that the visible portion of the CEA showed no damage or deformation that would be related to
'excessive downward thrust loading.
The inspection continued down the finger to the UGS support plate where it was then noted Page 2
Ii J
II I
j
that it's CEA fingers were oriented to the east in the UGS guide tubes.
This led to the assumption that the binding was located below the
- UGS, and was in one of the west most fingers.
To more fully inspect the full length of the CEA fingers, the UGS was removed from the vessel and placed in its storage location within the refueling pool.
At the same time this allowed the top of the fuel assemblies to be inspected.
A camera inspection of the top portions of the nine fuel assemblies centered by CEA 56 was performed, resulting in the finding of an indication of damage in the flare of the southeast guide post of fuel assembly P2C117.
CE had provided for a method to check each of the twelve fuel assembly guide tubes with a ball-check gauge to verify the diameter clearance within the tube, and to ensure the bottom of the guide tubes were free from debris that could prohibit the full travel of a CEA finger.
This inspection led to the discovery of a bal'l bearing in the bottom of the southeast guide tube post of fuel assembly P2C117.
This
. was removed by vacuuming the guide tube.
No other debris was found that could have affected CEA 56.
Caliper measurements of the ball gave a
diameter of 0.153 inches.
In parallel with the ball gauge inspection, a full-length finger inspection of the affected CEA was performed.
The camera inspection of the CEA fingers revealed several marks along the twelfth finger (this finger would reside in the southeast guide tube of fuel assembly P2C117).
It should be noted that CE System 80 utilizes a twelve finger CEA which has four fingers in the center fuel assembly and two fingers in each of four adjacent fuel assemblies (Fig. 8).
The location of the affected CEA finger is shown in Figure 8.
These'marks were located in the same orientation as the marks found on the flare of the fuel guide post in question.
A comparison of the mark on the CEA finger and the finger
- diameter, as measured on a video screen showed the mark to be approximately 1/8>> across.
EVENT EVALUATION As a result of these binding was due to finger and the fuel occurrence of this investigations, it was determined that the the ball bearing lodging between the CEA assembly guide post flare (Fig. 12).
The henomena is onl ossible if the ball bearin enters from the UGS su ort late travels down the UGS uide tube to the fuel assembl uide ost flare area.
This was further proven by taking a similar sized ball bearing, a
dummy fuel
- assembly, and a
dummy CEA finger (all dimensionally correct) and assembling them together in the same orientation as would have existed for CEA 56.
The finger was free to move in the outward direction but it was discovered that the finger became lodged by the ball bearing when moved inward and further insertion of the finger was prohibited.
Page 3
I o
The CEA finger O.D.
coupled with the guide tube I.D.
would prohibit the ball bearing from traveling down the tube with a
CEA finger in the guide tube.
The diametrical clearance between the guide tube post and the CEA finger is 0.1575 inches at the top of the guide post flare but the clearance narrows to 0.126 inches at the bottom of the guide post flare.
A review of the operating equipment in or around the UGS was performed; and it was determined that the ball bearing originated from the MST which is used to tension and detension the reactor vessel head studs.
The ball bearing recovered from the guide tube, plus ball bearings from the Multi-stud Tensioner (MST) were sent to an independent laboratory for metallurgical analysis.
The MST ball bearings. and the one removed from the guide tube were confirmed to be metallurgically equivalent using standard industry comparison techniques.
The ball bearing that was removed from the guide tube was found to be contaminated and not activated.
Therefore, the ball bearing was not in the reactor coolant system during the first cycle and must have been introduced during the refueling outage.
The most probable course of travel for the ball bearing is summarized below:
a ~
b.
The MST was removed, from the reactor vessel head to the storage location with the studs stored in the MST (Fig. 1).
The MST was being utilized for stud cleaning in the storage location (Fig. 1).
c ~
d.
While the stud cleaning was in progress, the reactor vessel head was removed to its storage location (Fig. 1).
The UGS was then removed to the UGS storage pit (Figs.
1&2).
e.
The ball bearing was released from the MST (Fig. 1).
g, h
During the course of work activities, the ball bearing fell into the UGS Storage Pit and onto the top of the UGS upper support plate (Figs.
1&2).
The UGS was reinstalled in the reactor vessel (Figs.
1&2).
The reactor vessel head was reinstalled.
7
~
During the course of heating up and running the RCPs, the ball bearing dropped between the UGS guide tube and the CEA finger (Figs. 3-12).
The ball bearing became lodged between the CEA finger and the fuel assembly guide post (Fig. 12).
Page 4
l t
t
k.
The CEA drop time testing resulted in the discovery of CEA mechanical binding.
Other pathways were reviewed and found not to be as probable because of Q.A.
inspections prior to lifting off the reactor vessel head.
Had a bearing assembly failed while the MST was positioned on the reactor vessel flange (during stud detensioning),
the ball bearing could have fallen, on to the floor of the refueling canal.
As the level in the refueling pool was raised and lowered during the refueling evolution, it would be conceivable that the ball bearing could have been swept into the UGS while it'as in the reactor vessel.
This scenario is highly unlikely since a
ball bearing traveling from the fuel transfer canal floor would fall into a gap between the reactor vessel and the flange (Fig.
2A).
As previously discussed, damage was found on the southeast guide post of fuel assembly P2C117.
It can be characterized as a
uneven contact mark on the flare region of the guide post with a minor amount of raised metal on the mid-height portion of the flare (Fig.
- 16).
The function of the guide post flare region is to provide a
smooth surface for entry of CEA fingers into the fuel assembly.
CEA alignment is such that no contact is made with the post flare region following reactor reassembly, even with the CEA fully withdrawn.
A review of the indications on the guide post confirmed that observed damage is confined to the guide post flare region of the guide tube (Fig. l2).
No damage that could interfere with CEA travel was evident in the lower portion of the guide tube since the ball gauge traversed the full length of the guide tube without binding.
In addition, there was no indication that the ball bearing traveled below the guide post flare region.
Since no CEA guide post flare area contact is made during operation and no material which could become loose was observed in the damaged area the guide post is considered acceptable for unrestricted continued operation.
CEA 56 is a twelve finger CEA.
It was inspected for damage caused by interaction with the ball bearing.
The initial observation made of this CEA immediately after the reactor vessel head was removed was that the CEA was leaning slightly toward the east axis of the reactor.
All the CEA fingers were in contact with the east side of their respective UGS guide tubes.
This suggested that the particular finger which was stuck was toward the west axis.
All the CEA fingers were inspected at the point which corresponds to approximately 30 inches withdrawn.
Although wear marks were observed on the east side of the fingers of the CEA, none were evaluated to be Page 5
l I
excessive or requiring further examination.
These marks were made either by normal contact with the guide tube during reactor trips or by contact with the guide tube/end fitting while the CEA was stuck.
The CEA finger which did interact with the ball bearing was examined over its entire length.
Evidence of scratches normally occurring due to metal-to-metal contact between CEAs and guide tubes were evident and evaluated as acceptable.
Scratches and occasional indentations were observed at several elevations on the CEA finger and generally within a
small area of the circumference of the finger.
The most severe indication was located on the CEA approximately 147 inches from the bottom of the CEA.
- Thus, when the CEA is 30 inches withdrawn, the damaged area of the CEA would be adjacent to the damaged area of the fuel assembly guide post. It could be characterized as a depression approximately.
1/8 inch wide at the surface of the CEA and approximately 3 inches long in the axial direction.
This corresponds to the region of the top of the B C pellet stack in the upper portion of the CEA (Fig. 21).
It was visually determined that the CEA cladding was not breached.
Based on the above evaluation the CEA remains acceptable for continued operation because:
0 0
0 All indications of contact with the ball bearing are above the region where swelling of the boron carbide pellets will occur in amounts large enough to close the diametrical gap with the cladding.
All indications of contact with the ball bearing were in an area above the,length of the CEA which enters the tight clearance buffer region of the guide tube at the bottom of the fuel assembly.
Sharp edges were not involved in the creation of damage.
The loads exerted on the CEA finger were within the original design basis axial loads.
The spider joints and upper nuts were examined and found to be satisfactory.
The entire length of the CEA was found to be free of any abnormal bowing.
Although the inspection supports the conclusion that the CEA cladding retains its structural integrity, the consequences of a cladding breach in the damage area have been reviewed.
Control rods supplied by various vendors have been operated with cladding cracks.
These cracks were near the rod tips, and were induced by a combination of corrosion and high tensile stress created by absorber swelling.
Even with this outward
- stress, the associated cladding deformation has not interfered with control rod drop.
In the Palo Verde
- case, there will be no outward strain of the cladding due to swelling, at the location of the indication.
Page 6
A breach in the cladding would result in exposure of the boron carbide pellets to reactor coolant.
Based on limited BWR data, the washout of boron carbide is minimal unless the rod is heavily irradiated (Boron-10 depletion of greater than 504).
Exposures required to cause these levels of depletion would only occur near the lower tip of the rods.
An evaluation was performed to determine the impact of a ball bearing in the RCS on core performance.
It was concluded that the following three items were the only significant concerns with respect to continued operation:
1)
The effects of a
ball bearing on core operation (potential for blockage and reduction of safety margin);
2)
The potential for the ball bearing to become lodged in a fuel assembly causing fretting damage that may impact cladding integrity.
3)
The potential that a ball bearing, within a
fuel assembly could travel from its location in the RCS to the point where the mechanical interference would prevent insertion of the CEA.
The effects of a stuck CEA is addressed in the safety analysis.
1)
Potential for flow channel blockage:
There is a very low probability that a 0.153" nominal ball bearing could fall or, otherwise be transported downward past the top fuel spacer grid into the fuel assembly or be transported upward past the bottom fuel spacer grid into the fuel assembly.
There are 14 cross-sectional flow areas (two per guide tube and at the four corners) that would 7ust allow the passage of the 0.156" ball bearing (See Fig.
20); this constitutes 1.1% of the cross sectional flow area
- of the fuel assembly.
The axial location of the fuel pins (within the fuel assemblies) do not extend to the edges of the top or the bottom spacer grids.
ANPP Safety Analysis Section and CE have performed an evaluation of the effects of the ball bearing within the fuel assemblies.
Their analysis demonstrated that a
ball bearing trapped in the fuel assembly could not reduce the margin to DNBR during transient events.
2)
Potential for fuel pin damage:
Another effect considered is that of a ball bearing trapped between a fuel pin and a spacer grid.
This could result in a limited amount of fretting.
In the event that this occurs it would be bounded by the allowed 14 failed fuel limit currently used as the design basis.
Page 7
Potential for debris immobilizing a CEA:
This concern can be broken down into two possible scenarios:
a).
The ball bearing falls into a fuel assembly guide tube; b)
The ball bearing rests in the fuel or on top of the fuel, and is picked up by RCS through the flow holes to the upper plate of the UGS.
The ball bearing at the bottom of a fuel assembly guide tube. will present no adverse consequences.
In order to move a ball bearing that is seated at the bottom of the guide tube it would have to be subjected
. to a hydraulic force-such as RCS flow.
In this scenario, the flow holes of the guide tube are above the elevation of the seated ball bearing.
Therefore insufficient flow exists to suspend or liftthe ball bearing and it would remain seated at the bottom of the guide tube.
During a CEA trip, the CEA will fall no closer than 0.2 inches from the bottom of the guide tube. If the turbulent flow within the guide tube, during a CEA trip, does cause the ball bearing to lift, the height that it could be lifted to is limited by the elevation of the guide tube bleed hole (less than 1.5 inches above the bottom of the guide tube).
At that elevation the CEA is approximately 99 percent inserted.
The geometries of the components involved make it highly unlikely that the ball bearing'ould wedge between the CEA finger and the guide tube.
If it is assumed that there may be
'a ball bearing in the core which cannot be identified or recovered.
This ball bearing may have been in the UGS and may have fallen into the core during reactor vessel reassembly.
When the RCPs are placed into service it can be postulated that hydraulic forces could result in the ball bearing being lodged in the same location which produced the mechanical interference of the CEA.
There is only one credible pathway which the ball bearing can follow that can produce an interference of the type observed in this event.
It would be necessary for the ball.
bearing to travel from its location in the core up into the upper plenum (Fig. 10), via flow holes in the UGS support plate and then down through the UGS guide tube, between the CEA finger and the UGS guide tube (Fig. 14).
An evaluation (documented on an Engineering Evaluation Report) shows that there is less than a 0.54 probability that this event could occur when full RCS flow is established.
The probability of the event is reduced even further during one RCP and two
RCP combinations.
This will contribute to a
Page 8
reduction of the probability of this event occurring by increasing the likelihood that a ball bearing, it if exists in the core, will be swept down the hot leg prior to Mode 2
operation.
An evaluation was also performed to determine the impact of a ball bearing on individual Reactor Coolant System Interfaces.
It was concluded that the following, items were the only concerns with respect to continued operation.
1 (1)
(2)
(3)
(4)
(5)
(6)
Reactor Coolant Pump Control Element Drive Mechanism Reactor Internals Chemical and Volume Control System Safety Injection/Containment Spray System Sampling and Instrument Sensing Lines Reactor Coolant Pump In the event up into the impeller and nozzles.
It affected.
that a 0.153 inch diameter ball bearing is sucked Reactor Coolant Pump, it should pass through the diffuser and out of the pump through the discharge is unlikely that hydraulic performance would be The radial clearance between the impeller O.D. and diffuser I.D.
is 6
mm (0.236 inch) so it is possible that the ball bearing could'pass through this gap and become lodged on the top of the impeller, particularly if there is reverse flow through the pumps as will occur with less than four pumps operating.
The ball bearing would not pass further up into the bearing or shaft seal area because the radial clearance between the impeller hub and bearing sleeve bore is 0.0275 inch; (Fig. 27). If the ball bearing size is reduced through wear, it is still unlikely that it would enter the pump bearing because the downward flow of seal injection water would prevent this.
The radial clearance between the impeller lower shroud O.D. and mating suction pipe I.D. is 1-2mm (0.04-0.08 inch),
so the ball bearing will not jam or pass through this area.
2)
Control Element Drive Mechanism The PVNGS Control Element Drive Mechanisms are located at the top of the Reactor Vessel head vertically in a no flow area.
An analysis was performed
. on the components of the CEDM to determine if sufficient clearance was available to allow for the passage of foreign material in the'size of a 0.153 inch diameter ball bearing.
The area between the drive shaft and the latch guide tube is the only area which would provide sufficient clearance for the Page 9
object to enter the CEDM motor.
Foreign material of this size and shape in this location would not cause or prevent a
In the event the object could travel against gravity within a no flow area, sufficient clearance exists above and below the latch in the window area of the CEDM where the object would be trapped with no detrimental effect to the CEDM operations.
3)
Reactor Internals Various paths of a
ball bearing were evaluated with the possibility of the ball bearing coming to rest at different locations in the internals other than what has already been discovered.
The first path considered with the Reactor Vessel Head removed was a ball bearing falling between the UGS upper flange and the core support barrel flange possibly continuing into the lower head region of the Reactor Vessel where the ball bearing, during operation, could be carried from the lower RV Head into the lower end of the fuel assemblies.
Ball bearing with a
.153 diameter would not cause a detrimental effect on the internals.
e A slight possibility is that the bearing could fall into a
Surveillance Capsule Holder.
This is very unlikely since the Holder is shadowed by the thick walled section of the Reactor Vessel.
However, if a ball bearing were to fall here, it is unlikely that it would interfere with the operation of the Surveillance Capsule Retrieval tool during an outage.
Finally, the ball bearing being captured in the Heated Junction Thermocouple guide tube, is an extremely torturous path and highly unlikely.
4)
Chemical and Volume Control System A.
Potential Paths to the CVCS 1.
2.
3 ~
4 ~
5.
,6.
7 ~
Letdown line from RCP Loop 2B.
RCS loop drains to Reactor Drain Tank (RDT).
Miscellaneous reliefs, drains, vents, leakoff, etc. to RDT.
Miscellaneous reliefs, drains, vents, etc. to Equipment Drain Tank (EDT).
Shutdown cooling to Letdown Purification line.
RCP controlled bleedoff to Volume Control Tank (VCT).
Safety injection mini flow to Refueling Water Tank (RWT).
Note:
Any lines with flow into RCS (charging, aux.
- spray, seal injection, etc) with check valves to prevent reverse flow are not considered as potential sources.
Page 10
I II 0
B.
Possible Scenarios for Ball Bearin 2 ~
3 ~
4 ~
5.
Lodge in pipe or component with no effect.
Lodge in pipe or component with subsequent failure of pipe or component causing loss of letdown or charging, or possibly a reactor trip/shutdown in worst case.
Breakup of ball bearing due to impact or mechanical force (pump, valve, etc.).
Chemical reaction of carbon steel ball bearing with Boric Acid with subsequent plateout of by-products or removal by purification.
Removal from system through filters, ion exchanger, strainers in CVCS.
6.
Cause reduced flow, blockage of flow and/or pressure oscillations.
C.
Im act of Ball Bearin in Path listed in Part A
1 ~
A ball bearing entering the CVCS letdown line would be stopped by the Letdown Flow Control Valves (LCV's) and/or the Letdown Bypass Orifice.
The cage on the LCV's provides a
strainer type effect preventing further travel.
The cage flow holes are tapered from 0.094 inches (outside) to 0.051 inches (inside).
The presence of the ball bearing in the inlet of the LCV's would probably cause pressure oscillations in the Letdown line due to continual blockage of one of the flow holes followed by subsequent unblockage as the cage rotates from the flow unbalance created by the blocked hole.
Similar pressure oscillations were experienced when weld slag was found at the valve inlet.
The ball bearing could break up over time due.to repeated impact and pass through the valve.
There's a
possibility that a small piece could then stick in one of the flow holes either reducing
- flow, causing unstable control or causing the valve to hang-up or stick.
The pieces that pass through the valve would flow to the purification filters and subsequently be removed either during draining of the filter or replacement of the filter element.
Bypass of the filters is possible through CH-355 which would allow the bearing to flow in the Letdown Ion Exchangers, Pre-Holdup Ion Exchanger,
- EDT, Pre-Holdup
- Strainer, Letdown Strainer, Gas Stripper, Holdup Tank, Boric Acid Concentrator, or VCT depending on valve Page ll
lineup.
The pieces would only reach the VCT if the purification filters were bypassed at the same time that the Purification Ion Exchangers were bypassed due to high letdown temperature (not a likely scenario).
Even if the pieces did reach the VCT, they would then go to the charging pumps and be pumped back into either the RCS or seal injection filters.
These small pieces would not impact charging pump operation.
A ball bearing in the Letdown Orifice Bypass line would remain upstream of the orifice with no loss in system performance.
The orifice is much to small to pass the ball bearing, flow (0.5gpm) in this line is infrequent, used only during recovery from loss of letdown when flow has been lost for greater than, 30 minutes and when at normal operating pressure and temperature.
2.
If the ball bearing made its way to the low points in the RCS loops, it would eventually make it to the RDT
, for processing when the loops are,drained at which time the ball bearing would remain in the RDT or be pumped to the Reactor Drain Filter.
3 ~
4 ~
As mentioned in item 2 above, any input to the RDT is processed and the ball hearing and/or pieces of the ball bearing would be removed.
Any input to the EDT is processed as is the contents of the RDT.
5.
Any particle (ball bearing) introduced to the letdown purification system from the shutdown cooling system would be removed.(2 microns) as in normal purification mode mentioned in item 1.
This flow enters downstream of the LCV',s and Letdown Bypass Orifice.
6.
Its very unlikely that any ball bearing or part of a
ball bearing would pass by the first RCP seal since seal injection pressure should be greater than RCS pressure causing flow into RCS.
The clearances are much too small even if seal injection was lost or stopped assuming the seal is not grossly failed.
7 ~
Mini flow return from the Safety Injection System to the RWT is a potential flow path 'but very unlikely to be the source for the ball bearing because of the piping configuration.
If it did, the ball bearing would end up on the RWT bottom; the suction strainer for the Low Pressure Safety Injection/High Pressure Safety Injection (LPSI/HPSI) pumps has a
0.09 inch screen particle retention capability.
Page 12
l i
1 II
Entry into the CVCS is the most desirable place for the ball bearing to go in order to remove it from the RCS.
However, the size is large enough that it may not pass the LCV's to the purification system.
This is acceptable because if the ball bearing did not make it to the LCV's, it is, anticipated that the Back Pressure Control Valves (BPCV's) will experience oscillations in conjunction with pressure oscillations and be easily detected.
At that time the. parallel LCV could be placed into service and the LCV experiencing oscillations could be isolated for removal of the bearing.
There is a possibility that presence of
. a ball bearing will not cause noticeable pressure oscillations and remain undetected.
In this
- case, long term degradation of the cage could occur due to impact velocities of the ball bearing.
The carbon steel ball bearing would probably deteriorate before the 17-4PH cage.
Based on the above it is determined that operation of the CVCS with a ball bearing in the system will not compromise safety of the plant or personnel.
5)
Safety Injection/Containment Spray System An evaluation of the effect of the presence of a ball bearing in the Safety Injection System (SIS)/Containment Spray System (CSS)/Shutdown Cooling System (SDCS) indicates the following conclusions:
During the unlikely event of"an Engineered Safety Feature actuation, the screens in the RWT and containment sump would not allow the bearings to pass (the screen size is designed to filter a maximum particle size of 0.09 inch).
As a result, the bearing will not enter the system during post accident operation.
The sump
'and RWT are the only suction sources for the HPSI.
t During operation of the SDCS, it could be assumed that a
bearing in the RCS would make it to the hot leg suction lines.
- However, due to the size of the SDCS, it would be anticipated that a
bearing would pass through the system and either return to the RCS or be drawn into the purification system of the CVCS.
No damage would be expected to the major components, such as the SDC heat exchangers and LPSI (or* Spray) pumps.
A bearing, lingering in the system from previous SDC operation, is not expected to prevent SIS/CSS operation.
Due to the flow under the seat orientation of the systems'eader isolation valves, a
bearing will not prevent their opening.
The LPSI mini-flow orifices would pass the bearing to the RWT.
The spray nozzles would also pass the bearing.
Page 13
0
6)
Sampling and Instrument Sensing Lines The PVNGS sampling and instrument sensing lines are located such that the migration of a ball bearing is all but excluded from entering the lines (not located at the bottom of piping).
In a sampling line there is no flow until a sample is drawn.
At this time the flows are very low and a ball bearing would have to be resting directly at the entrance of the flow path (suspended) in order to enter the line.
There is no flow through the instrumentation sensing lines attached to the reactor coolant system.
This combined with the small diameter of the sensing line, assures that the probability of a ball bearing blocking a sensing line is extremly low.
Safety class instrumentation is comprised of four channels which would reduce the likelihood that safety systems would not perform their design function.
The preceding analysis of the ball bearing within the reactor coolant system has provided assurance that the impact of a ball bearing would be minimal.
Nevertheless, extensive visual inspections of all accessible areas of the UGS upper support plate were performed using a drop camera and light to provide assurance that there is no debris in the UGS, that could interfere with CEA movement.
The camera was lowered into each CEA shroud area and around the shroud itself to e
provide a
detailed inspection.
The UGS upper support plate was subsequently vacuumed and all vacuumed debris was collected.
The inspection and vacuuming did not provide evidence of any ball bearings.
After reassembly of the reactor vessel internals the reactor cavity was drained and a piece of debris was found and removed from the flange area of the UGS, outside of the guide tube shrouds.
This debris was confirmed by the inspection videotapes to be on the UGS flange during the UGS and CEA inspections.
This debris was identified as a 7/8" x 3/l6" roll pin from a tool that had been used to uncouple the CEAs from their extension shafts (to prepare CEA 56 for camera inspection) while the UGS was in the laydown area.
This was confirmed by matching the two sheared ends.
A sighting which later proved to be a carbon steel roll pin was noted on the inital viewing of the video tape, however, it was not identified as foreign material.
A corrosion layer from the carbon steel roll pin obscured any sharp edges or observable depth of the object.
When the roll pin was recovered the video tape was reviewed again and the faint edges of the pin were observed with dimensions matching that of the recovered pin.
A corrosion resistant 52100 type bearing steel ball bearing would not have been obscured by it's corrosion layer.
Page 14
IV CONCLUSION/CORRECTIVE ACTIONS The evaluation of the minor damage done to the guide post indicates it will not.
prohibit full power operation.
An evaluation has also determined that the damage to the CEA finger will not prevent the CEA from performing its design function providing a negative reactivity insertion when called upon by the Plant Protection'ystem.
This will be verified by the performance of the normal post-outage CEA drop-time test.
CE evaluated the damage documented by the video inspection of the CEA and has concluded that it could be used for continued operation based upon the locations and extent of the damage.
The fuel assembly guide tube post was also video inspected and evaluated by CE to be acceptable for continued operation based upon the limited amount of damage.
In order to ensure that all accessible debris was removed, the UGS top plate, UGS flange, and UGS lift rig were extensively inspected and the top plate was also vacuumed.
Following the evaluation of this
- event, and an analysis of the potential consequence of debris in the
- RCS, the following remedial actions are being implemented.
During the RCS filland vent a variety of Reactor Coolant Pump combinations will be run.
This will provide flushing of the fuel assemblies as previously discussed.
2 ~
3
~
4 ~
5-6 All CEAs will be exercised following the filling and venting, in Mode 5, to provide assurance that no debris is in a location that can interfere with the CEA movement.
In the event that debris is evident in the UGS, it will be detected immediately during testing.
The CEA exercising and the CEA drop-time test will be performed at normal operating temperature and normal operating pressure to assure CEA operability and conformance to Technical Specifications.
The pre-criticality run time for RCP combinations will be approximately four days.
The MST design for Units 1
and 2
have been modified and Unit 3 will be modified prior to use to eliminate the possibility that a
bearing will be released during operation.
The design change of the bearing assembly will be verified prior to its use.
Prior to Mode 2
entry, operators will be instructed to review Procedure 41EP-lZZOl "Emergency Operations" and Technical Specification Section 3/4.1.3.1 "CEA Position".
Page 15
Investigations into the occurrence of this event identified areas of concern with the foreign material exclusion program in that it was not designed or intended to exclude material from component failure, e.g.,
MST bearing failure.
The following actions are being taken to enhance the foreign material exclusion program.
l.
A specific procedure dealing with foreign material
'-,'exclusion'ill be developed to assure the controls are adequate to eliminate the introduction of foreign material into plant systems or components specifically associated with safety-related systems.
2 ~
3.
4 ~
A specific training program will be developed and presented to all appropriate personnel when the foreign material exclusion procedure is issued and thereafter as part of annual retraining.
Appropriate supervision and management personnel including Q.A. and ISEG will be trained in their responsibilities for foreign material exclusion.
Implementation of the action items listed in 1 through 3
will be completed by August 31, 1988.
Page 16
ATTACHMENT B FIGURES The following list of figures are available for reference:
1 ~
2 ~
2A.
3.
4.
5.
6.
7 ~
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22
'3.
24.
25.
26.
27.
MST/UGS Floor Layout Internals Lift Rig Layout Reactor Vessel/Internals Interface Modified UGS Assembly UGS Detail UGS Upper Plate Detail UGS Lower Plate Detail UGS Lower Plate Detail CEA Locations UGS Detail Fuel/CEA/UGS Interface Fuel/CEA Finger/UGS Tube Interface Jammed Ball Bearing Sketch Reactor Flow Paths Reactor Vessel Arrangement Fuel Assembly Upper End Fitting (Fuel)
Lower End Fitting (Fuel)
Fuel Assembly Outline Fuel Assembly:
CEA Guide Tubes Fuel Spacer Grid 12 Finger Control Element Assembly Multiple Stud Tensioner (MST)
MST Stud Handling Vehicle (SHV)
Detail of MST SHV Bearing Control Element Drive Motor CEDM Grippers Reactor Coolant Pump Component Locations
,II o
~
0
~ 0 0 0
~ ~0 ~
~ ~ ~
~
~ ~
00 0 0 0
~ 4
~ 0
~
0 0
~
~
<0.'.
~
ro ee ~
0
~
~
~
Oo
~e f0.
~
1
~
~ ~
0
~
0
~ '
~
o
~
ffgAO sroRC-
~ 0
~'
~
~0 ~
~
~
~ ~ 0 e 0
~
~
0 0
0 0
~
~
~ ~
<<oooeeo ~0 RE/Clog n
r r r r UG khf0o ppgg FAILEO li 85th+G p<r~..
8ggg plG
)8 0
~. 0'~5 t,
oo
~
~
eo $o o
~ ~, ~
~I 0 ~
4~ 0a
~0
~ ~ 0 0 0
~
~
~
~
~
~
l,p
~ ~ ~
, ~ 0
~ coo HST LAYDoug C ~
~'
0
~
~
0
~
~ QA
' '~'
~,
0
P IJI
~(f
~', "'r
~ r
~ ~
r
~
~
(
J ~
~ ~
~ ~ r
~
~ ~
~ ~
~
(
C.g
~ r""'i
~,
~
~ ~
'rt(I ~ I V>>
(
~
f
( ~t 4w
( f, ~
~
~ '
~
~ I Q
~ (
~,
"~
O.
t ~ rr
- .t G
Ifl.'
J i ~
~
I(1
CEA 56 CEA Spider FIGURE 2A UGS Shroud tube (tgpical)
UPPER GUIDE STRUCTURE Hold down ring REACTOR YESSEL CORE SUPPORT BARREL CEA Extention shaft Hot Leg outlet flow UGS Upper plate Flow Hole (tgpical)
CEA finger UGS Tie - Tube Site of Baii Bearing which caused Mechnical Interference UGS Lo~er plate GUIDE POST Fuel hssemblg Guide Tube Fuel hssemb1g upper end fitting
ij
a o
<<+II MODIFIED UPPER GUIDE STRUCTURF ASS Eel BQ'ug.
v
0
Cv IVO H
ll Cl.OIS
~ l
~
~ I ia vit 44vvvtl V//// /i/a, 4444 OI//Iav
/I/It
/4v 4 44 aim livia urt Ottr iv C
nsj is~
K~EQ Z
J
~ Slit Y-7 s
CCT)C)
~I ICit vtsfrr
/IVt KCCV a
I i
iult Aviv llC C IC B
SC J I
~ o/Irc/Ts s,oCI) ro oc czhRAU4e tofvttr.ooT Cgt)
Ce OT T
TCCR RIRT RR T
sc ~czc P'r'-o ICOS SIC RCCb CCC ETC g i-')e Zsjcr ITZOIT YVg~R l sge 9'>>
'R CCRC R
CIHW
/COL CIVIC WSIO SCCIIOTC S g 10 Ysv R445 C.Calvt44 ISMCT44 +Et gtj 4
5 TACF CC/
gc/
rpccrtttsoD ifOC COC Rf'VCC Pf>> WCCO 440 PAIOIOCaitvt ICfcro.
VjCRatl YCjCC
~
O C-h na ctrtt wfcc) 5ffIIOTCS DETACLY SCOCC I OI//IOTCO 5ISC DLCTRIL Z scocC Iolucra oCC t/fO/O
~
~
c Cigars oa tl I,t OCICC OC>> WCCCT 50 ACIYO RXC TCTA g 5 TT PCOC/C Troll'V WACC ovctt T//Ia sf/tfrrt
/4/v cc/ vto CCTTICrtccs PIOOCCOOOC sfc tiorfcl tOTO AC40iCOO 144444.
CSKCCSCIO CCIO ll il8 g ce rrcxcro>>
W WCCC IWCIO Ttvs Cf/I/arrl,SICR Csltvlo RCVICCTVCO r/OOCCXICTC sCE 4/orfs lid CSCC Crt @fr scf off cr Srcfr J C sit CIA Rtr 145 CCMC4T44 KKm~R vtC, CCWC OHCKTlCCC TCT S 44%7VKC
0
N 0 e s Ivtrrlppvpcrvv+v I
tt~V~I ryCC Rfrv trfLO ITLl IACVOORRCVI
.V fICOCES 5 CAkC I OCttRTCR SICf Wi %fr C rIOLCS SOS ~,Vrr f TCACCS
@~were 0 0~
0 0 S
a APPROPRIATC PScl5 IDCICTI~
Ec NPLAca.1NurctRA<5A,IAAFotvtN.
o tc1 5TAIrlo Witrl LCIW t TILC55 O t.. 5'TOA C CXSPLAVCCCS MABEL PLLtdrl 'TO ISORrrIAI OcrRPAC'K y
5 IvfIlrr o
(ia rr OVIIOrlleftlVCTCX ICCsCCWtft) laic SCrCACrrrPCr fICC
~ IV
~r ddj~TO~
TTO AAQ ltfrQg->
TPTCSCV CSO rr/u I
0 0
~
t OSC S$P 0
5J.ttt 55C C rIOLCS d.eC rsrr c rcAccs PO~ers nr I I c.i rrtSttftr 5 rtrCC5 6'6$ C 0
0
+
+
0 Q
+
0 0
0 0
0
~o 0
0 0
0 0
0
~
O.O 0'0 cot "
blOIOlc flba8 SIC tt C
gkV
~f Pffft dfC
~ SINCT5 dl C.rrv ltfC r CV.VVOdfC frrIPrcC SVr lp OC rorlrrrrr ArPrV.VIS.
r.fvs ltd' ZO.CCO SIC tO.Vtt Jctctdf Vyfttasc OO VMV5dSC Cr Ctt XOItX', At VtIIOORt OPIION lINOLC5 KARMIC II 0 tl'OlA%tt)RAT~t DELL'ltOCVVOLt'b Otic'A>MO LOCAttO OV XtV PLAN C ScI11IIIOILD lN vtlR PLALL CXIlb SYII A tert t 55 TrrccC fvRFpKS5, TO dC Caattlrrr'uc f@)
rrrSAI 4IIO dt's vrcocvs
+
/+
cl.rtd dSC d.ldo DSC A.'drr
~ 4/M4CPSI
~
~
I'os prrsl S:~CSC V rCXCS t ILOC.CSO E
t! ~
~ IA.Vu
It
.4k ikh 4L
/1k HQEHBKI QO~,.QOi,QO...O~NQO...QO~QO...OO.,
Do o)tQoo QGo)tQoo QnQoi Qoo)
QO"QOjFQl"POVQO QOiFQO~ QOF(QO QOt<QO iQO)~QO iQ)rQO7(Q
>A.
Ak AL+,
/iL (AL+
AL (Ah%
AL (AL /il AL rim>PAR Ac yAL+$(iLgr/ALA ArAhb+~AL~v/4L+r+RL+<Oljv(AL>%Abbr(ALEE</1k'(Akv(ALhv(Akr(Aber(A'AlA&rAL>%Li g@
(QO 8@~</QO.FG g45g) g@5(@L.Pg~~P~qlw(y A~ (i',+A AL
.AR /il
+Ak il (A'I AL
+AL)
AL Ak Ail AR, AL 41k AiI (ALA e]
<z
'pter e 'pmay:
~
<e:
nr r
i>
<erg ~r:eq'rger]
aiQi~igiamkLQiakg~n>QiSssQii aQia4ii~iiaoils4g(Aa@Qiana Q
QeitQoi Oe"NI
~)fQa Qo'~i'Qe O'Q"Qo~'Q'0 Q Qoi~iQo>>
Qo~~
A AL Qk Ai>lk AL (Ak AL A+I AR (Ak, AL AL> il (ALX AL ALR AL MLX
'4~
+%TED 4+>'~F
'<~
QItg
'4<
<%Ty'+~/
'11
4<>
yVJ 4+<'
QOo'QO>'iQO A)(e Oe>[AO+.QOo)tAOo Q'-
mQOe WOe tAOe ROAM QOo1(AOe QOe),
A+ ok Rle 4)is ~AL~v(AL~WAtv1@v(AN(ALhw(ALhw/kPhr (1 1+v(ALv(ALQ~+1L+v~ALNNAL)M+i4
. Q...Qj;Q, (spy,,g...'QXQ.](Q,>[,
47"0,'Qx'ci il&
/p 5
g7Ji7
L
ROLL TO I+60:oeo DVI EZPANSION dddrACI idScalL I/AotwArldAdw4 1 g NA 580
~
g 5ZDCN I
fACE I
ITIOIMA AID ROLI. II'EMIZ ID%
S ZEAL REDVCTION IN ddt L MKAA'05$0&N TRIS LENIN l8 22+'I'.
AAL COVTACT DCTlk2d PLRZE AKO INSERT ALL AROUND RT TNS iNTZAS'A E BOTTOM OF PLATE l7
+SECTION H-H ADrdrru srrS SCALE s FVtLSIZE IVOSLAVNCPLIÃ4IDMOCES
/DAOr~EN zur05CC 5CCT. Ah<A DETA'//
o'a ZoaerI /zgrg KCTION AA-AA Nor<neo gas SIIILE i FVLL 5IZC QB SLEElED LOCVZIOJIS
f f
1
12 ELEMENT FULL LENGTH CEA's H
4 ELEMENT FULL LENGTH CEA's Q
4 ELEMENT PART LENGTH CEA's 13 TOTAL 89 CEA's S DENOTES SPARE CEA LOCATlONS 8
CONTROL ELEMENT ASSEMBLY LOCAT10NS
M
~
~
z I/0 ave g vs'4.
iIpcA CCS.
(soj 9)
)x~$ )
'isa))
+s
~
'+ii-sv 0 0 0 0 0 0 0 0 0 0 0 0 0 0
-f.
)
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 Nrrtg rv07K'S' 5P1t IO Blair'D 000000000000 00 00000000000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 000'000.0000 OOOO 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
M>662lzD 2 AS'SV I htOOISIED UPPER GU.'DE 5 TWCWRE AS'
CONTROL
- ASSEMBLY,
.". HROUD BUFFER PIN 12 fINGER CONTROL ELEMENT ASSEMBLY GALE T PCENUVl
.J UPPER GUIDE STRUCTURE BASE PLATE (TOP PLATE FLOMf HOLE CONTROL ELEMENT SHROUD TUBE FUEL ASSEMBLY ALIGNMENTPLATE FUEL ASSEMBLY UPPER END FITTING FUEL ASSEMBLY Fuel/control element/upper guide structure interface
CEH Finch~
Q.$ S TQ GE
,5@
Z.D.
s6 O. D.
/. Pf 2.D.
l.005 F49'7 9
o 0.
G uiDc-t'OSW AP/'$1.
~~(wgey Fu,u.y)
~ggbRW@ J
- ggpL,
+5Kb-m~~p Q RibL 7 cc88 O. 9'9g S.
FK6. 24
0
CEW Fw6Eg LLGS TUBE O. Ir."
OD I.812 2+elNED QaLr 8Eaaiag
- o. r53 "ag l575 Cca~~<E'.
Oo g la.re, plz" e
0~ o.o.
Fu.c J assai io I V AIPPBW~<<f au.n>p PosT
>qsv ru~iy)
~ives r-~>"
o.
9 Z.P F~aw ASST~<
gybe 748E o.w QD
$ 7I lL
1
TOTAL FLOW
/lll
,Q$ kg IBS>lli, I I
040~
I 2
V 0>
4 56" 7
~ MAIN FLOW
~ BYPASS FLOW THRU OUTLET NOZZLE CLEARANCE THRU INSTRUMENTED
'CENTER G.T.
<THRU SHROUD.BARRR.
ANNUL'US THRU CENTER GUIDE TUBES THRU OUTER GUIDE TUBES THRU ALIGNMENTKEY-WAYS THRU UPPER GUIDE STRUCTURE SUPPORT PLATE REACTOR FLOVl PATHS R/9 Jg
)I
a a a a h 6 4 UPPE.R PLEMUM HOLDDOWN RING CEA SHROUD ASSEMBLY UPPER GUIDE STRUCTURE p
11
~
~ 1
~ ~ VIE
~I
~ ~ Vt
~t t 1
~
t~
~
~
~P
~
V V,
~t V
~
~
~
V
~ "I'att I" ~
t
- It 4.;
~V V
~ V
~<<) '
V W IV ALIGNMEiNT KEY CORE SUPPORT BARREL INLET NOZZLE OUTLET j
NOZZLE CORE SHROUD llew-R SLLPPORT PLaTE 150" ACTIVE CORE LENGTH I
INSTRUMENTATION ASSEMBLY FUEL ASSEMBLY LOWER SUPPORT STRUCTURE FLOW BAFFLE INSTRUMENTATION NOZZLE REACTOR VESSEL ARRANGEMENT
VPPER END FITt'ING I
I Ll I
,'aoaaaaaoaaaoanol
- pgr, GVIDE TVBE ASSEMBLY Ia~a=~"-()~n~auaaaaI S PACER GRED Qo,'o FUEL ROD Qo I
I BOTTOM VIE>Y aaoaoaaaaaoaoaoa LOMiER END FITTING Fis. is FOEL ASSB1EL'(
. --":'-P.is%
)"1",MB)P PEP I
g Jl I
waft Q f
I 1
4
~M I
(8 (1 ~() C,r().,
>Piiff& (S
~ l I
~ g II
<c Jt li ijl TOP VIEW,i I
~ u,'.,
j I
N'...,g'.:.
~ 4 ~.
WIi~ "<<<
gw,A.'.';j..'..-,:,,
I j
I g <<~ ej' ll i g
>. t g
I~ ~;l 1
~M
(
~
~i
"~
SECTfAN D D
J I
030303030203DZ 02
~
g g
0
~
4 s
I S
4
~
e e
0 0 0 iI xxix
(,M
0 h
If
~f L
0
~8
~I
~'
0
~
c0
$ 0 0'o9<
It}
I
~I InXOn 4
+
~
~I I+V
~
f I(
nI0n 4C
~ II 0
0 0
r'<,
/
r 4 I
/
nIO Y
u t
il h
I
TOP gy//
R2&i0 f4 MC ior BOTTON CENTER GUIDE TUBE FUEL ASSEMBLY< CEA GUIDE TUBES
e
,g7 (p'Q WELD LOCATIONS TOP & BOTTOM 0~
S PACER GRID T+
GRID S P RING STRIP GRID PERIMETER STRIP CEA GUIDE TUBE LOCATION FUEL ROD
lf ij f
If l
I I
j
GRIPPER COUPLING HOLDDOWN SPRING LOCKING NUT SPIDER 0
0 Qo 0
0 0
244 5/8 REF PLUNGER PVI SERIAL No 5 PLANT ID Nos FULL I.ENGTK CONTROL ROD ASSEMBLY END FITTING PLENUM HOLDDOWN SPRING STAINLESS STEEI SPACER 135 1/2 B4C PELI.ETS AREA dF Dh I'I0 I-.E B4C PELLETS FELTMETAL 12 1/2 FELT.
METAL5 REDUCED DIA. 8 C
PELL6S 1 1/2 REDUCED DIAMETER 84C PELLETS STAINLESS STEEL SPACER C-E amma
/
~
FULL LENGTH CONTROL ELEMENTASSEMBLY (12 - ELEMENT)
0'
Nl e
'Lu
}j
)I t t I
~lJ 8'
I
/
I l<
0 x~
h l.~+
g I
~~
Ii
/Vgl.7/pgp SW8
~EJVSJd&E+
P2d. ZZ
tms~l III!I
'~ ~
I ~
~g.
0 O
I III zR L
I gs l ~
~R IS.I7 L
C R$
1 04 4
I l
l I L
Qc
~l l
CI t.
.(
i l
J
~
g/
I S 7Mb
/4&rrdr.reed l~ddrc.W l~
~See S is uJHJC H FtfIlk0 HS7 3
RIIIc.
I 5 T
>Tug HzwoIIIrg kwrc<+-
F24 Zg
0
v 1 p I
~
~
l t
REED SWITCH ACTUATING MAGNET EXTENSION SHAFT UPPER LIFT COIL UPPER LATCHES III '"
I UPPER LATCH COIL'RIVE SHAFT LOWER LATCHES Imari LOWER LIFT COIL LOWER LATCH COIL REACTOR NOZZLE CONNECTION CEDVI OPERATIONAL CHARACTERISTICS
~
~
o o
h ~
o
~ o
/3
11
> ~7&Plmr~
ASS< 4~
Reactor Coolant Pump Component locations.