Title: / Reactor Restack / Lesson Plan #: / NME10C000303
PALO VERDE
NUCLEAR GENERATING STATION
Mechanical Maintenance Training
Classroom Lesson
Mechanical Maintenance Training / Date: 3/2/2011LP Number: NME10C000303 / Rev Author: CURT CLUFF
Title: Reactor Restack / Technical Review:
Duration : 4 HOURS / Teaching Approval:
INITIATING DOCUMENTS
Task Analysis of Tasks
REQUIRED TOPICS
CRDR 9-7-0493: Addition of Reactivity Management into Maintenance Training [TCS 97-2013]
CONTENT REFERENCES
31MT-9RC30: Reactor Vessel Head Removal and Installation
CRDR 9-4-0865: Use of handrails for tie-off during CEDM venting [TCS 95-0392]
31MT-9RC01: Reactor Vessel Ventilation, Cable Support Structure and Insulation Removal and Installation
31MT-9RC31: Reactor Vessel O-Ring Replacement
31MT-9RC33: Reactor Vessel Upper guide Structure Removal and Installation
DCP 13-PM-ZC-200: Permanent Reactor Cavity Pool Seal Ring [TCS 94-0518]
DMWO 000752491: Modifications to alignment of UGS when placing in pit
LESSON PLAN REVISION DATA
Mar 02, 2011 / Curt Cluff / Incorporate Human Performance and Prevent Events strategies and changes to procedures with Simplified Reactor Head components [CRAI 3585595]Tasks and Topics Covered
The following tasks are covered in Reactor Restack :
Task or Topic Number* / Task StatementLesson: / Reactor Restack
RHD012 / Vent CEDM
RHD007 / Clean and lubricate vessel studs and holes, inspect and gauge
RHD009 / Replace reactor head seals
RHD011 / Latch/unlatch extension shafts from the UGS SLMs
RHD010 / Inspect, install, and remove guide pins
RHD002 / Remove/replace reactor shielding during refueling
RHD001 / Remove/replace reactor ductwork during refueling
RHD004 / Remove/replace reactor internals during refueling
RHD006 / Remove/install cable support structure
RHD003 / Remove reactor head and place on head laydown area and replace after refueling
Total task or topics: 11
TERMINAL OBJECTIVE:
1 / When given the applicable diagrams and drawings, the Maintenance Mechanic will, state the basic steps necessary to re-install the Reactor Vessel Head and Internals in support of the refueling processdemonstrated by passing a written exam with a score of 80% or better.
1.1 / State the basic steps necessary to install the Upper Guide Structure
1.2 / State the basic steps necessary to install the Reactor vessel Head.
1.3 / State the basic steps necessary to install the Reactor Vessel Head Insulation and open the access covers.
1.4 / State the basic steps necessary to install the CEDM Cable Support Structure.
1.5 / State the basic steps necessary to install the Reactor Vessel Missile Shield and reconnect CEDM Cooling System.
CONTENT / METHODS & ACTIVITIES /
I. Motivation / Focus student attention on “What’s In It For Me”.
II. Pre-Job Brief
A. Pre-job briefing on the day’s activities modeling the use of the Palo Verde Standards & Expectations, Preventing Events
B. Focus On Five (Task Preview)
Familiarize worker with the scope of work, task sequence, and critical steps.
1. Critical Steps (Terminal Objectives)
When given the applicable diagrams and drawings, the Maintenance Mechanic will state the basic steps necessary to re-install the Reactor Vessel Head and Internals in support of the refueling process, demonstrated by passing a written exam with a score of 80% or better / PVNGS Standards & Expectation book (Focus on five) Highlight the critical steps (Terminal Objectives) on the power point presentation.
2. Identify error likely situations (error traps)
a. Discuss at least one specific error likely situation / Look at Error Precursors in S&E Book
3. Identify the Worst thing that can happen. / Apply to the setting you’re in. (Lab versus Classroom)
4. Identify specific error prevention defenses to be used. / What defenses can we employ to prevent the “Worst thing that could happen”
5. Identify actions to assure proper configuration control. / This may not be applicable in every training setting.
a. Two Minute Drill - After lunch at a minimum / At instructor's discretion - not to interrupt class flow
III. Lesson Introduction / Introduce the lesson material
A. Lesson Enabling Objectives / Slide Read and/or discuss the lesson objectives
EO01 State the basic steps necessary to install the Upper Guide Structure
EO02 State the basic steps necessary to install the Reactor vessel Head.
EO03 State the basic steps necessary to install the Reactor Vessel Head Insulation and open the access covers.
EO04 State the basic steps necessary to install the CEDM Cable Support Structure.
EO05 State the basic steps necessary to install the Reactor Vessel Missile Shield and reconnect CEDM Cooling System.
TO: 1 / When given the applicable diagrams and drawings, the Maintenance Mechanic will, state the basic steps necessary to re-install the Reactor Vessel Head and Internals in support of the refueling process
demonstrated by passing a written exam with a score of 80% or better.
EO: 1.1 / State the basic steps necessary to install the Upper Guide Structure
CONTENT / METHODS & ACTIVITIES /
I. Crane and Administrative Preparation
A. With no load, verify the crane CANNOT enter the exclusion zone and 18’ limit is functioning
B. Prior to fuel loading, the hook should have been positioned for the UGS pick
1. Normally big hook on inboard side
2. Outage management can vary this depending on situational efficiency
C. Obtain key and bypass the exclusion zone interlock
D. Ensure SRO/LSRO and Maintenance Department Leader present
II. Hook up the UGS / Slide UGS Lift Rig with Tie Rod Installed
Point out Tie Rod Assembly
A. Install the tie rod assembly (if removed)
1. Requires 4 people on the plate
2. Must all push out simultaneously and lower end pieces into the column blocks
3. As able, install pin fully then continue to lower until all three pins are installed
4. Install spiral retainers
B. Rig to Load Pin on the tie rod assembly
1. Verify the load pin is turned on
2. Ensure the handset for the load pin is functional
III. Install the UGS
A. Lift the UGS from storage a few inches
1. Stop after a few inches and verify no CEAs are hanging lower
2. Ensure UGS is floating free indicating crane hook is centered
3. Continue lifting until UGS is high enough to clear any obstructions
B. Move over the Reactor and center over the Rx Vessel
1. Use cameras to monitor movement
2. Orient the 213° orientation plate with the alignment pin in stud hole #33.
C. Lower UGS into Core Support Barrel. Monitor load readout carefully and stop lift if readout decreases by 8,000 lbs. / Slide UGS in Core Support Barrel
1. Spotters monitor guide bushing on guide pins for hang-ups.
2. Continue lowering until UGS is fully seated on the hold-down ring
IV. Lower support plate
A. Prepare self-latching mechanisms
1. Move pins to the top hole
2. Allows ratcheting of the barrel
B. Lift Tie Rod Assembly and CEA Support Plate Assembly until dead bolts can be retracted (approximately 3/8 inch) and retract dead bolts. / Slide Column Actuator Assembly
C. Lower the hook in slow speed once the UGS flange seats on the holdown ring until support plate assembly is resting on the guide plates 193 1/4 inches above the bottom of the column actuator assemblies. / Slide UGS Lift Rig in down position
NOTE
Operations should be lowering the refueling pool water level as the CEAs are inserted into the core.1. Monitor with cameras to ensure CEA spiders go through the tophat
2. Monitor the SLMs using the telltales and stop the downward movement if one of them lifts up indicating the CEA is hanging up
3. In some cases, the CEA may hang up
a. The SLM barrel can be raised to drop the CEA
b. May need to rotate the CEA to align it with the hole
V. Release the CEAs from the support plate assembly
A. Remove the quick release pin from the slotted pin on the Self Latching Mechanism / Slide CEA Extension Shaft Self Latching Mechanism
B. Manually lift handle and insert pin into slotted pin
C. Perform these steps for remaining 88 CEA extension shaft self latching mechanisms
D. Lift plate until link blocks engage underside of spreader weldment assembly / Slide UGS Lift Rig in up position
1. Move 6 dead bolts out to their extended position.
2. Lower CEA support onto the dead bolts / Slide Column Actuator Assemblies
VI. Remove the UGS Lift Rig from UGS
A. Unbolt UGS lift rig from UGS
1. Verify it is totally unthreaded / May ask them how you know – measurement
2. Clear the platform
B. Lift UGS Lift Rig clear of alignment pins and bolt it down in its storage location.
1. CSB stand
2. Must be rotated to enter hold-down bolt cones
3. Take care not to hit the stairs
C. Remove hook from load pin
1. Verify the load pin is turned off
2. Turn off the handset
EO: 1.2 / State the basic steps necessary to install the Reactor vessel Head.
CONTENT / METHODS & ACTIVITIES /
I. Remove Rx Vessel "O"-Ring / Slide Rx Vessel Head "O"-Ring
Slide Rx Vessel Head "O"-Ring Location
A. The following parts are used for attaching the O-rings to the head:
1. Retaining Pins
a. About ¼” dia
b. Are pressed into the head
c. Must be below the surface of the head
2. Retaining Clips
a. Inserted in slots in the O-ring
b. Fitted over the retaining pins
3. Retaining Rings [aka snap rings]
a. Hold the clips in place
b. Placed over the retaining pins and released into the recessed area of the pin
B. Prior to entering the LHRA
1. ALARA briefing will be held
2. Tooling verified correct and staged
3. Practice removing and/or installing the rings with the snap-ring pliers outside the LHRA to ensure you can maneuver the snap ring pliers well enough to place the rings on and off of a retainer pin / Lessons Learned: the standard snap-ring pliers may have pins that are too large – verify acceptable before entering the LHRA
a. An extra pin can be set up on a vise to practice with
b. This skill will be used inside the LHRA, so ensure you are comfortable with the tooling
C. While supporting "O"-Ring remove the Tru-Arc rings and "O"-Ring retainer clips / Slide Rx Vessel Head "O"-Ring retaining system
1. Requires snap-ring pliers (ensure they fit and are the correct size before entering the area under the head)
2. Remove the retainer rings using snap-ring pliers
a. Generally, the O-ring will not fall down
b. Remove the associated retainer clip also
c. If there is evidence of Boron, you may need to spray the pin with water or Gosh to dissolve the Boron before you can lower the clip off the pin
D. While supporting the O-ring, use a tool and remove the old "O"-Rings
NOTE;
Take special care not to scratch the O-ring mating surface.
1. Slight pressure applied to inner surface of the O-ring
a. Use only the minimum pressure required to loosen the O-ring from the groove to prevent damage to the sealing surfaces
b. Sometimes tapping the O-ring with a dead-blow will loosen the O-ring enough to allow it to drop
c. In extreme cases, engineering has authorized drilling a hole in the bottom of the O-ring and inserting a tool (packing puller, e.g.) to pull the O-ring down
2. Lower the O-ring to the shelf [support stand]
3. Repeat for outer O-ring
E. Cut up each "O"-Ring and dispose of it per the RP's direction
II. Prep for New Rx Vessel Head "O"-Rings
A. Clean the Rx Vessel Head Flange and stainless steel clad "O"-Ring grooves [Generally a utilities task]
B. Ensure "O"-Ring retainer pins do not protrude below mating surfaces of the "O"-Ring Grooves.
C. Clean Rx Vessel Flange of any residue. / Point out how retainer pins should be installed.
D. Examine Rx Vessel Head, "O"-Ring grooves and mating surfaces on Rx Vessel Flange for any nicks and scratches and repair as necessary in accordance with proper documentation.
III. Install new Rx Vessel Head "O"-Rings / Use this slide to explain the installation of new Rx Vessel Head "O"-Rings
A. Clean "O"-Rings to class B cleanliness and ensure it is free of nicks and scratches
NOTE
"O"-Rings must be symmetrically supported during installation process. "O"-Ring clips must be verified to be securely fastened to support pins.
B. Place personnel 90° apart to prevent damage to the "O"-Ring from bending stresses
C. Install the "O"-Ring
D. Install "O"-Ring retainer clips and Tru-Arc (snap) rings
E. Repeat above steps for the remaining "O"-Ring
CAUTION
"O"-ring surfaces are susceptible to corrosion. Do not allow foreign materials (e.g., Molykote) to come into contact with Rx vessel head O-rings.
I. Install Rx Vessel Head
A. Administrative Prerequisites / Slide
1. A maintenance Department Leader must be present during the entire process
2. An SRO/LSRO must be present
a. Grant permission to lift the head and install it
b. Communicate water levels for permission to proceed at various points / Prevent Events Tool: Procedure compliance
B. Clearly mark holes #6 and #33 to aid in proper head orientation.
C. Ensure ready to lift
1. All loose material and debris is removed from the reactor head
2. Shroud doors are secured for transport
3. 38’ limit switch and 15’ exclusion interlock verified
D. Engage the Polar Crane to the Rx Vessel Head Lift Rig Bail
E. Raise head 1-3 feet
1. Inspect the lift rig again
2. Check and level as necessary to within 0.020" per foot of diameter
a. Prevents damage to Rx Vessel "O"-Ring if it were to be set cocked on the Rx Vessel Flange.
b. Ensures CEA Extension Shafts will not interfere with Extension Shaft Guide Funnels (underside of head) as the RX Vessel Head is lowered to the Rx Vessel Flange.
CAUTION
This task will be accomplished in an area of high radiation levels.F. When over the dance floor, lower to 146’ elevation
1. Remove the 38’ limit switch bypass key