ML18065A398
| ML18065A398 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 01/12/1996 |
| From: | Smedley R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9601220099 | |
| Download: ML18065A398 (27) | |
Text
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l'OWERINli lllllCHlliAN"S l'ROliRE5S Palisades Nuclear Plant: 27780 Blue Star Memorial Highway, Covert, Ml 49043 January 1 2, 1 996 U S Nuclear Regulatory Commission Document Control Desk Washington, DC 20555 DOCKET 50-255 - LICENSE DPR PALISADES PLANT PRELIMINARY THERMAL ANNEALING REPORT, THERMAL ANNEALING OPERATING PLAN, SECTION 1.5, ANNEALING METHOD, INSTRUMENTATION AND PROCEDURES At a meeting on June 6, 1995, we discussed with the staff our plan to anneal the Palisades reactor vessel (RV) during the refueling outage currently scheduled for the middle of 1998. In support of this effort, we plan to submit the final Thermal Annealing Report (TAR) in the third quarter of 1996 after the results of the Marble Hill reactor vessel annealing demonstration have been evaluated. The TAR will include the information recommended in Draft Regulatory Guide DG-1027, Format and Content of Application For Approval For Thermal Annealing of Reactor Pressure Vessels. To permit NRC review of the TAR to begin before the Marble Hill results are known, we will make a series of submittals of preliminary TAR sections as they are developed. This letter provides the fifth of those submittals.
The attachment to this letter contains the Thermal Annealing Operating Plan Section 1.5, Annealing Method, Instrumentation and Procedures. The attached information is presented in the format recommended by Section C. 1 of DG-1027.
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I' A CMS' ENER6YCOMPANY
SUMMARY
OF COMMITMENTS This letter contains no new commitments and no revisions to existing commitments.
Richard W. Smedley Manager, Licensing CC Administrator, Region Ill, USNRC Project Manager, NRR, USNRC NRC Resident Inspector - Palisades Attachment 2
ATTACHMENT 1 CONSUMERS POWER COMPANY PALISADES PLANT DOCKET 50-255 THERMAL ANNEALING REPORT SECTION 1 THERMAL ANNEALING OPERATING PLAN SECTION 1.5 ANNEALING METHOD, INSTRUMENTATION AND PROCEDURES 24 Pages
1.5 ANNEALING METHOD, INSTRUMENTATION AND PROCEDURES 1.5.A Method of Heating Vessel The basic heating system uses high velocity combustion technology to deliver the required heat to the reactor vessel (RV). Unlike conventional gas fired vessel heat treatments, however, the high velocity gases do not come into direct contact with the RV contaminated surfaces. Instead, the heating system is enclosed and isolated from the reactor vessel and the high velocity gases (essentially hot air) are passed through a heat exchanger, which is placed inside the reactor vessel. The heat exchanger, in turn, delivers the required heat to the RV wall by radiation heat transfer. Figure 1. 5. A-1 shows a conceptual overview of the heating system.
Refer to Section 1.6.A.1, Heating Apparatus, for a more detailed description of the individual components of the heating system.
The annealing operation will not degrade the primary system or other equipment, components, and structures. Section 1.2 describes the reactor and it's attachments. Section 1.3 describes the other equipment, components, and structures affected by the annealing, including where applicable, justification for exceeding the original design limits of these components. Section 1. 7 describes the analysis performed to justify that the annealing will not adversely affect the reactor vessel and other components.
1.5.B Method of Measurement This section describes the type and location of measurements planned for the annealing operation. Measurements will be taken to aid in the control of the heating apparatus, to monitor compliance to annealing operating conditions described in Section 1.4 and to verify the annealing limiting parameters described in Section 1.8 are not exceeded. *These parameters were established by the annealing recovery requirements described in Section 1.4, and the analysis described in Section 1. 7. As a result, the on-line measurements of temperatures and displacements described here will ensure that allowable values of stress and strain are not exceeded, while the temperatures required for recovery are achieved; Rather than measuring the strains directly, strains will be predicted based on correlation to actual temperature measurements and determined acceptable based on the stress analysis methodology described in Section 1. 7. Section 2.1 further describes the.monitoring of stresses.
Measurement locations were determined based on the results of analyses and the corresponding instrumentation location criteria described here. The selected measurement locations must be adequate to verify that the annealing was successful from a recovery standpoint, while verifying that the process does not exceed the limits established in the thermal stress analyses. Measurement locations must also be adequate to verify that the temperature of the reactor cavity biological shield wall concrete does not exceed allowable limits. Thus the measurement locations have the following requirements:
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Document the time temperature history of the RV wall within the annealing zone to confirm reactor vessel material recovery. (See instrument zones K, B, C and D described below.)
Measure the RV axial and/or circumferential temperature gradients and associated temperatures at the flange, nozzles, shell and the flow skirt region for acceptable temperatures and resulting stresses and strains. (See instrument zones A, B, C, D, K, L, M, and N described below.)
Measure the displacement of the RV bottom and PCS piping, and PCS piping temperatures for acceptable resulting stresses and strains and equipment support boundary restraints. (See instrument zones A, E, F and I described below.)
Measure the temperature of a RV support structure. This will be used to monitor the RV support structure temperature and the concrete temperature in the vicinity of the supports. (See instrument zone G described below.)
Measure the temperature of the reactor cavity biological shield wall liner to monitor maximum concrete temperatures. (See instrument zones H and J
- described below.)
Redundancy of measurements will be provided so that a loss of sensor(s) will not result in a loss of critical data or controllability.. This is accomplished primarily through the use of backup sensors at measurement locations. As a supplement to backup sensors, and as a primary means of redundancy where backup sensors are not be installed, redundancy is achieved by the symmetrically located instruments due to the symmetry of the structure and loads, and* by the proximity of one or more instrument locations where symmetry does not exist.
The symmetric case provides redundant measurements if the structural temperatures and resulting displacements are symmetric. The structural design and applied loadings are essentially symmetric about the vertical centerline of the vessel and therefore it is reasonable to expect symmetric response. The asymmetric case provides redundancy assuming the vessel measurements are not symmetric.
Although this is not a predicted response it is possible that non-uniformities in heat transfer or structural constraints could cause variations in the results in the circumferential direction. In the event of loss of sensor(s) at such locations, the data would be obtained for these cases by interpolation using two or more sensors.
This represents an acceptable approximation.
Although the number and locations of sensors may change, the final arrangement will comply with the location and redundancy requirements described above.
Selection of the types of sensors and locations will consider the results of the Marble Hill RV annealing demonstration.
Use of these measurements to aid in the control of the heating apparatus and the associated requirements for these measurements are discussed in Section 1.5.D.1.
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Simllarl.¥, use of these measurements for verifying annealing operating limitations and the associated requirements for these measurements are discussed in Section 2.1.
The primary instrumentation described above covers the instrumentation to monitor annealing operations. Secondary instrumentation will supply general information on equipment status. Sensors will be used to monitor biological shield supplemental cooling air inlet and outlet temperature for the reactor cavity annulus forced circulation. The role of this class of instrumentation is described in Section 1.5.D.1.
1.5.B.1
. Internal Temperature Measurements 1.5.B.1.1 Measurement Locations and Number of Sensors Internal temperature measurements will be taken at thirty locations within the an*nealing zone (K) of the reactor vessel, six locations within the lower guard zone (N), and twelve locations in the upper guard zone region (M) below the hot and cold leg nozzles. Measurements will also be taken at two locations (zones E and F) inside each hot and cold leg nozzle near the PCS piping interface. Measurements (zone L) will be taken at six locations in the flange region and six locations in the region adjacent to and above the hot and cold leg nozzles. These planned locations are depicted in Figures 1.5.B-1 and 1.5.B-2 (for E and F nozzle zones only), and are summarized by zone in Table 1.5.B-1. This arrangement has been selected in order to obtain sufficient information on the temperature gradient from the top of the reactor vessel to the lower shell course during the annealing process as well as the uniformity of temperature in the same horizontal plane at different elevations. For redundancy, primary and backup sensors will be installed at all locations. Table 1.5.B-1 shows the resultant total number of sensors.
1.5.B.1.2 Installation Method All RV internal temperature measurements will be made with direct contact surface temperature sensors. All sensors in zones K and N, and the zone L and M sensors that are between nozzles, will be supported by a retractable probe delivery mechanism that will be attached directly to the heat exchanger assembly. During insertion of the heat exchanger, the probes will be retracted to clear the smallest diameter of the reactor vessel. Once in position, the probes will be extended to contact the RV wall. Each column of sensors will have a dedicated actuating mechanism that penetrates the reactor vessel top cover (RVTC, described in Section 1.6.A.5.1) and that can be operated from above. Provision for maintaining proper contact force will be provided by either a gravity based aesign or by a spring loaded mechanism.. Provision for remotely actuating the probes during annealing so that the sensor contact points can be "reset" will be. provided.
The sensors in zones E and F will be attached to the nozzle thermal barriers which are described in Section 1.6.A.5.4. Installation of these sensors will therefore take place with the thermal barrier installation. Zone L and M sensors that are TAR1/12/96 1.5-3
c.oincident with the nozzle centerlines will be attached to the thermal barriers as "outriggers", or to retractable mechanisms similar to those used in zones K and N.
Installation will be performed using written procedures approved for the annealing operation. Procedures will include quality assurance measures to verify proper installation, positioning and operation of the sensors.
1.5.B.2 External Temperature Measurements 1.5.B.2.1 Measurement Locations and Number of Sensors The planned external temperature measurement locations are presented by zone in Table 1.5.B-2. These locations are also depicted in Figure 1.5.B-2. Primary and backup sensors will be installed at all measurement locations on the RV outside diameter (zones A, B,. C and D) and at all other measurement locations (zones G, H and J) for redundancy. Table 1.5.B-2 shows the resultant total number of sensors.
1.5.B.2.2 Installation Method All measurements will be made with direct contact, surface temperature sensors.
All sensors will be installed using fixtures that ensure good thermal contact with the surface being measured and reduce the influence of the sensor on the local temperature of the measured surface. Sensors in zones A, B, C, D, G and H will be installed from the bottom region of the reactor cavity. Sensors in zone J will be installed from above or below. Sensors in zone A will be manually installed.
Sensors in zones B, C and D will be installed using remote tooling to access the RV wall through the 3/4 inch gap between the reactor vessel and the insulation.
Sensors in zone G, H and J will be installed using remote tooling to access the nozzle support structural steel and the reactor cavity steel liner through the gap between the ~V insulation and the reactor cavity steel liner.
- All sensors will be installed using procedures written and approved for the annealing operation. Appropriate quality assurance measures will be implemented in these procedures to verify proper installation, positioning and operation of each sensor.
1.5.B.3 External Displacement Measurements 1.5.B.3.1 Measurement Locations and Number of Sensors The planned external displacement measurement locations and number of sensors are presented by zone in Table 1.5.B-3. These locations are also depicted in Figure 1.5.B-2. Prime and backup sensors will be installed on the RV outside diameter (zone A) for redundancy. Single sensors in three dimensions will be installed at all other measurement locations (zone I). Table 1.5.B-3 shows the resultant total number of sensors.
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-~
1.. 5.B.3.2 Installation Method All measurements will be made with direct contact, linear displacement sensors.
Displacement sensors will b.e rigidly installed between the surface being measured and a suitable reference point to measure displacement of the surface relative to the reference point. Sensors in zone A will be installed from the bottom region of the reactor cavity and will be rigidly mounted between the reactor vessel and the reference point. Sensors in zone I will be installed outside the biological shield and will be rigidly mounted between the PCS loop piping and the reference point.
The final correlation between the measurement locations, reference points used and directional values provided by the analysis discussed in Section 1. 7 will be obtained analytically as part of the installation process. All sensors will be installed using procedures written and approved for the annealing operation. Appropriate quality assurance measures will be implemented in these procedures to verify proper installation, positioning and operation of each sensor.
1.5.C Description of Instrumentation This section describes the instruments planned for on-line monitoring of the measurements described in Section 1.5.B. This description includes a discussion of the sensor and data acquisition system (DAS) type, calibration requirements, achievable accuracy, and achievable sampling frequency. The requirements for accuracy and sampling frequency associated with the control of the heating apparatus are discussed in Section 1.5.D.1. Similarly, the requirements for accuracy and sampling frequency associated with requalification are described in Section 2.1. Although the system design is subject to change, the final system will comply with the general location requirements described above,.and the accuracy and sampling frequency requirements described in Sections 1.5.D.. 1 and 2.1.
1.5.C.1 Internal Temperature Measurements The following is a description of the planned internal temperature measurement instrumentation to be used during the annealing.
1.5.C.1.1 Sensor and DAS Type Reactor vessel internal temperature measurements will be made using type 'K' thermocouples. These chromel-alumel thermocouples have a usable range of 32 ° F to 2500°F, and are routinely used in heat treating applications at temperatures between 32°F and 950°F. The thermocouple tip will be stainless steel or inconel sheathed. The thermocouple wire will run continuously from the sensor tip to above the RVTC, and will be protected mechanically using a stainless overbraid, or a continuation of the sheath. If required, the wire will also be sealed to protect against moisture during submersion or vessel drying.
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Data from the internal thermocouples will be collected using a computerized, multi-channel DAS, with analog input relay cards having on board, hardware based cold junction compensation.
1.5.C.1.2 Calibration Requirements The DAS hardware will be calibrated using procedures and standards controlled under a Quality Assurance Program which meets the requirements of 10 CFR 50 Appendix B. The thermocouples and related hardware (connectors, etc.) will be supplied with manufacturer's certificates of conformance stating that the devices are supplied in accordance with ANSI MC96. 1 1982, and that the calibration data is traceable to NIST. Accuracies tighter than those specified in ANSI MC96.1 1982 will be achieved through the use of calibration curves created for a particular lot of thermocouple wire, also traceable to NIST. The expected instrument bias uncertainty of the sensor and measurement hardware alone is 3 ° F.
1.5.C.1.3 Measurement Methodology Bias Uncertainty To compensate for the error (measurement methodology bias uncertainty) due to thermal interaction between the temperature sensor probes, the heat exchanger, and RV wall, correction factors will be applied to the measured data. These correction factors, or calibration coefficients, are determined by testing of the sensors under simulated annealing conditions. Ongoing research at Sandia_ National Laboratories, as well as previous work related to similar probes used in non-commercial annealing efforts, indicates that fairly large correction factors (as high as 100 to 200°F depending on conditions) may be necessary.
Correction factors for the measurement system design specific to Palisades will be determined based on detailed analysis' of heat transfer between the RV wall, the sensors, and the annealing heat exchanger, as well as empirical data developed from tests of a prototypical system. The annealing demonstration at Marble Hill will serve as final verification of the adequacy of the correction factors and the system accuracy overall by comparison with instruments which are welded to the wall.
1.5.C.1.4 Achievable Accuracy An uncertainty analysis will be performed to estimate the total measurement uncertainty resulting from application of the above instrumentation. This analysis will consider sources of uncertainty that include instrument bias uncertainty, precision uncertainty, positioning bias uncertainty, and measurement methodology bias uncertainty. Based on initial evaluations the total measurement uncertainty for the internal temperature measurement system will not exceed 25 ° F.
1.5.C.1.5 Achievable Sampling Frequency Temperature measurements must be obtained (scanned) at a r:ate sufficient to fulfill two requirements. The rate at which data is required to be recorded, and the TAR 1 /12/96 1.5-6
rnanner. in which it is required to be stored and archived, are specified in Section 2.1. The rate at which data is required to be provided to the heating system operators is described in Section 1.5.D.1.
To fulfill these requirements, the DAS will be capable of achieving a scan rate for internal temperature measurements of once every two minutes.
1.5.C.2 External Temperature Measurements 1.5.C.2.1 Sensor and DAS Type The planned type of sensors are 100 ohm, 4-wire, platinum, resistance temperature detectors (RTD). The RTD sensing elements will be encapsulated in stainless steel sheaths. Similarly, the high temperature portion of the lead wires will be encapsulated in stainless steel sheaths. The sensors and lead wires are completely sealed for mechanical and environmental protection. RTD sensors of this type are routinely used in temperature measurement applications from 32 to 950 °F. The resistance of the RTD sensor will be measured by multi-channel DASs with 4-wire resistance measurement capability.
1.5.C.2.2 Calibration Requirements The sensors and DASs will be calibrated using procedures and standards controlled under a Quality Assurance Program which meets the requirements of 10 CFR 50 Appendix B.
- The sensors and DASs will be calibrated together as a system by direct comparison against NIST traceable temperature standards at multiple points over the required temperature ranges. Individual sensor calibration coefficients will be determined from the calibration process in accordance with NIST Technical Note 1265. The expected instrument bias uncertainty of the calibrated systems is 1 °F.
1.5.C.2.3 Achievable Accuracy An uncertainty analysis has been performed to estimate the total measurement uncertainty resulting from application of the planned instrumentation.
- The uncertainty analysis considered sources of uncertainty including instrument bias uncertainty, measurement methodology bias uncertainty, positioning bias uncertainty, and precision uncertainty. The results of the uncertainty analysis are presented in Table 1.5.C-1.
1.5.C.2.4 Achievable Sampling Frequency Temperature measurements must be obtained (scanned) at a rate sufficient to fulfill two requirements. The rate at which data is required to be recorded, and the manner in which it is required to be stored and archived, are specified in Section
- 2. 1. The rate at which data is required to be provided to the heating system operators is described in Section 1.5.D.1. To fulfill these requirements, the DAS will be capable of achieving a scan rate for external temperature measurements of once every two minutes.
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1_.5.C.3 External Displacement Measurements 1.5.C.3.1 Sensor and DAS Type The zone A sensors for displacement measurements are high temperature linear, variable, differential transformers (LVDT). LVDT's are recommended for measurements in zone A based on the commercial availability of LVDT's that can operate in environmental temperatures of 900 °F. The LVDT signals will be measured and recorded by multi-channel DASs.
The zone I sensors for displacement measurements are linear, resistance, displacement transducers (LRDT). LRDT's are recommended for measurements in zone I based on their simplicity of operation and commercial availability for application in environmental temperatures up to 200 °F. The LRDT signals will be measured.and recorded by multi-channel DASs.
1.5.C.3.2 Calibration Requirements The sensors and DASs will be calibrated using procedures and standards controlled under a Quality Assurance Program which meets the requirements of 10 CFR 50 Appendix B. The sensors and DASs will be calibrated together as a system by direct comparison against NIST traceable standards at multiple points over the required displacement ranges. Individual sensor calibration coefficients will be determined from the calibration process.
- The expected *instrument bias uncertainty of the calibrated LVDT systems is 0.02 inch. The expected instrument bias uncertainty of the calibrated LRDT systems is 0.004 inch.
1.5.C.3.3 Achievable Accuracy An uncertainty analysis has been performed to estimate the total measurement uncertainty resulting from application of the planned instrumentation. The uncertainty analysis considered sources of uncertainty including instrument bias uncertainty, measurement methodology bias uncertainty, positioning bias uncertainty, and precision uncertainty. The results of the uncertainty analysis are presented in Table 1.5.C-2.
1.5.C.3.4 Achievable Sampling Frequency Temperature measurements must be obtained (scanned) at a rate sufficient to fulfill two requirements. The rate at which data is re.quired to be recorded, and the manner in which it is required to be stored and archived, are specified in Section 2.1. The rate at which data is required to be provided to the heating system operators is described in Section 1.5.D.1. To fulfill these requirements, the DAS will be capable of achieving a scan rate for external displacement measurements of once every two minutes.
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1.5.D Annealing Operational Steps Including QA The RV annealing on-site activities outlined below will be controlled by written procedures that will be reviewed and approved by Consumers Power prior to site implementation. These procedures will include:
Administrative limits and required actions to maintain compliance with parameters established in Sections 1.4 and 1.8.
Actions required should the instrumentation in Section 1.5.B become inoperable.
Annealing operation controls.
Quality assurance measures needed to obtain an effective annealing operation.
Processes to control radioactive contamination before, during, and after t~e annealing operation, including monitoring and control of any airborne radioactivity.
Provisions to protect personnel from radiation exposure and to protect instruments and equipment from temperature.effects during the annealing operation.
A general outline of the planned sequence for annealing follows:
A.
Activities Performed Prior to or Concurrent With Core Off-Load.
Assembly of the combustion system and ducting outside of containment.
Move vessel disassembly equipment out of containment staging areas after use.
Move heat exchanger sub-assembly and annealing equipment into containment.
Assemble the heat exchanger and support structure.
Install instrumentation outside the reactor vessel and on lo.op piping.
Install temporary storage pads for the core support barrel (CSB).
Install ducting and insulation in containment.
Set up support equipment such as RV internals airborne contamination control system, refueling cavity airborne contamination control system and RV drainage/purge system.
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Remove RV wall surveillance capsules and transfer to the spent fuel pool.
Place shielding in preparation for internals lift. See Section 1.9, ALARA Considerations.
B.
System Setup Following Core Off-Load.
Move the CSB to the CSB temporary storage pads.
Lift and install the shielding into the refueling cavity and place around the CSB. Refer to Section 1.3.F for a description of the equipment and the process to be used for storage of the reactor internals.
Lift the UGS over the CSB and lower into the CSB.
Align the UGS to the CSB using the CSB alignment keys and seat the UGS onto the CSB flange. Spacers on the CSB flange can be used to limit the engagement of the UGS keyways with the CSB alignment keys to provide additional interface clearances.
Complete the setup of the shielding and airborne contamination control system for the RV internals.
Perform pre-anneal tests of the heat exchanger and ducting system to verify the function of the ducting, instrumentation and heat exchanger.
Perform pre-anneal inspections, reference Section 2.2.
Install nozzle thermal barriers into the inlet and outlet nozzles. The nozzle thermal barriers allow water drainage.
Drain the refueling cavity, and install the refueling cavity airborne contamination control system.
See Section 1.9, ALARA Considerations.
The cavity is drained to the RV flange prior to lowering the heat exchanger into the cavity to allow removal of the reactor cavity seal, stud hole plugs, detector well opening seal plates, etc.
Move the heat exchanger to the refueling cavity. The level can be lowered to the bottom of the loops through the normal drain-down procedure.
Lower the heat exchanger over the guide pins and into the reactor vessel while the reactor vessel is being drained through the nozzles.
As the heat exchanger is lowered further into the reactor vessel the water will be pumped up through a pipe which is installed down through the center of the heat exchanger and RVTC and sent to the tilt pit drain until TAR1/12/96 1.5-10
the heat exchanger is fully inserted. See Section 1.6, Thermal Annealing Equipment.
After wateJ:::.temoval from the vessel, the RV drainage system will be withdrawn and the RV.purge system will be connected. This will further dry out the reactor vessel and also control airborne contamination during the drying and annealing process.
See Section 1.9, ALARA Considerations.
Remove vessel guide pins and sleeves.
Secure the heat exchanger in place and install duct sections.
Actuate internal instrument delivery mechanisms and perform checkouts.
All potential liquid flow paths to the reactor vessel, both internal and external, via the primary coolant system piping (including safety injection and shutdown cooling systems), containment spray system, demineralized water system, fuel transfer tube and reactor cavity area will be drained or tagged out of service. Palisades will utilize its normal administrative control procedures for equipment tagging.
C; Reactor Vessel Anneal System Start-up Refer to Section 1.5.D.1, Annealing Controls and Application, for a more detailed description of the annealing system operation.
Begin a low temperature dry out to remove all traces of water from the reactor vessel. The reactor vessel will be vented during this phase to allow any steam to be vented through the RV purge system described earlier. See Section 1.9, ALARA Considerations.
Perform final checks of the combustion system, temperature control, and monitoring system. Check all records and obtain final approvals.
Verify the reactor vessel dry out is complete.
D.
Perform Annealing Cycle Increase the combustion system output to control reactor vessel heatup rate until the reactor vessel reaGhes the annealing temperature.
Maintain temperature and soak for entire annealing period.
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- 1. 5-11
E..
Reactor Vessel Cool Down and System Removal Cool down at controlled rate using the heat excha11ger to take the vessel to an ac~~._t_able temperature for system removal, tentatively less than 212°F.
Install RV guide pins and sleeves.
Remove RV purge system and necessary ducting connections.
Restore water supply sources in preparation for reactor vessel filling.
Lift the heat exchanger and the attached RVTC from the vessel. The water can be raised to the RV flange while removing the heat exchanger assembly_.
Install the reactor cavity seal, stud hole plugs, detector well opening seal plates.
Fill the refueling cavity.
Remove nozzle thermal plugs.
Perform post-anneal inspections, reference Section 2.2.
Place temporary shielding in preparation for UGS lift.
Remove internals shielding in preparation for UGS lift.
Lift UGS from CSB and move UGS to its storage stand.
F.
Confirmatory and Final Anneal Program (Reference Section 2.3)
Perform fit-up test for wall surveillance capsule holders:
Move CSB into the reactor vessel and perform fit-up test.
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G, Restoration From Annealing Move surveillance capsules into RV wall holders, if available. (Potential to perform. prior to CSB installation.)
Remove instrumentation, as required.
Disassemble and move annealing equipment out of containment.
Remove CSB temporary storage pads.
Remove combustion system and ducting outside containment.
1.5.D.1 Annealing Controls and Application This section describes how the hardware is used to control the annealing process, and specifies the required accuracy and sampling frequency of the RV temperature measurement instrumentation. The RV internal and external temperature measurement instrumentation described in Sections 1.5.B and 1.5.C serves to provide feedback for the operators who will control the annealing and to verify annealing operating limitations are not exceeded. Both the reactor vessel and the heating system are extensively instrumented. For each zone of the heat exchanger, instrumentation provides air and gas flow rate information, inlet and outlet temperatures, and exchanger shell temperatures. The heating apparatus is described in Section 1.6.A.1. The gas control equipment, including the temperature controllers and their available modes of operation are described in 1.6.A.1.3. The temperature DAS, which forms a major part of the overall control system, is described in Section 1.6.A.4.
The operators of the heating equipment will heat the reactor vessel in a specified manner: at a specified maximum rate, to a specified annealing temperature range, and within specified allowable temperature differentials, etc. Procedures will govern the operation of the equipment and the heating of the reactor vessel. It is important to note that despite the presence of valuable information such as displacement measurements, the operators can only affect changes in vessel temperature. The operators will control to temperature conditions that have been previously defined by the thermal stress analysis described in Section 1. 7.
Operation of the heat exchanger is considered safety-related. Use of the instrumentation with the annealing system will be in accordance with procedures as part of a safety-related process.
The annealing heat exchanger has five independent zones of control. Changes in control output on a particular zone will affect large regions of the reactor vessel.
For any zone, the inlet air temperature is the only parameter which is changed as a result of control feedback. For combustion heating applications, where a large capacity heat source is used to supply heat in a distributed manner, the temperature control entails more than a single, carefully chosen temperature sensor connected to a zone temperature controller. Control requires on-line assessment, TAR1/12/96 1.5-13
QY the.operators, of internal and external RV temperature data. The inlet air temperature responds almost instantaneously to changes in control output, the heat exchanger responds slowly and the reactor vessel responds very slowly.
The effects on the reactor vessel of any possible heat exchanger circumferential gradients or local hot spots due to heat exchanger characteristics have been identified and analyzed. The effects on the reactor vessel and instrumentation are minimized by the thermal averaging behavior of the reactor vesseL The operators ability to control the process is enhanced by the control features.
For the annealing, it is likely that primary feedback to the temperature controllers will be from the inlet air temperature sensors on the heating system. The available control modes of the zone temperature controller, described in Section 1.6.A.1.3, would be applied to the inlet air. However, if it is found that a particular sensor,
- such as on the heat exchanger shell, will provide more suitable control feedback
- than the air inlet sensor, then this new sensor can be directly connected to the controllers. For combustion heating applications, such changes in the selected control sensor are made during the cycle. Lessons learned during the demonstration project at Marble Hill regarding the suitability of a particular control scheme for RV annealing will be incorporated into training and/or process controls for Palisades.
The computerized temperature DAS will also provide the operators data feedback.
The DAS will display measured temperatures, gradients (axial, circumferential, and through wall) and ramp rates, and extensive summary information to the operator.
This data includes which sensors in each RV zone are the highest and lowest, their values, the average RV zone temperature, and the total temperature spread over specified regions. In addition to standard alarming features, the system will provide advance warning for any values approaching out-of-spec conditions. With this DAS, the operators will continuously assess changes in the RV temperature, and make anticipatory adjustments to the heating system. These adjustments will be decided by the operators based on observed response of the vessel to changes in control output.
The following is a general description of the main control phases of the annealing cycle. The process is governed by the allowable conditions for the reactor v~ssel,
- as well as the allowable design parameters of the heating equipment itself (i.e.,
maximum allowable shell temperature and ramp rate per zone). Although all of these items are continuously monitored, the key parameters monitored during each phase of the cycle are discussed below. Adjustments are made per zone based on temperature sensors within or directly adjacent to that zone.
The first phase of the cycle consists of heating the exchanger itself. This involves bringing the heat exchanger to it's lowest effective temperature of approximately 700°F. At this temperature, radiant heat transfer between the reactor vessel and heat exchanger becomes significant. During this phase, the key parameters monitored are the rise rate on the heat exchanger itself, the hottest and coldest TAR1/12/96 1.5-14
tempe(atures on the heat exchanger, and the hottest and coldest temperatures on the reactor vessel.
The second phase consists of heating the reactor vessel. This involves a continued rise in the heat exchanger temperature, and a resultant rise in RV temperature. The heat exchanger is raised at a rate not to exceed its allowable, and not to exceed
- the allowable RV heatup rate. During this phase, the key parameters monitored are the heat exchanger and RV heatup rates, the hottest and coldest temperatures on the heat exchanger and reactor vessel, and the gradients on the reactor vessel.
This phase continues until the heat exchanger reaches a hold temperature, which is that required to maintain the desired heatup rate on the reactor vessel as it approaches the annealing soak temperature (but limited to the maximum allowable.
temperature on the heat exchanger itself).
The third phase consists of transitioning into the RV annealing soak band. This phase begins when the highest RV temperature approaches the lower soak range.
When this point is reached, adjustments in the RV heatup rate are initiated, so that there is no risk of overshoot. These adjustments are accomplished by lowering the heat exchanger shell temperature to slow the heatup rate of the reactor vessel.
During this phase, the key parameters monitored are the RV heatup rate, the hottest and coldest temperatures on the heat exchanger and reactor vessel, and the gradients on the reactor vessel. Adjustments continue until the highest RV temperature stabilizes within the annealing soak range. The lower RV temperatures will continue t~ rise until the minimum temperature reaches the desired soak temperatur~.
The fourth phase consists of soak, or holding the reactor vessel within the annealing temperature range. At this point small adjustments are made such that the heat input to the reactor vessel is as required to overcome losses through the insulation. During this phase, the key parameters monitored are the hottest and coldest temperatures on the reactor vessel, and the gradients on the reactor vessel.
The last phase consists of cool down of the reactor vessel. This phase involves a lowering of the heat exchanger temperature, and a resultant decrease in RV temperature. The heat exchanger temperature is lowered at a rate not to exceed its allowable, and further limited by the allowable RV cooling rate. During this phase, the key parameters monitored are the heat exchanger and RV cooling rates, the hottest and coldest temperatures on the heat exchanger and reactor vessel, and the gradients on the reactor vessel. This phase continues until the burners are at the minimum possible firing rate, at which time they are shut off. The blowers will remain on, to provide active cooling of the reactor vessel. At this point, the reactor vessel temperature will tend to decrease at a rate less than its allowable, due to its considerable mass, and hence, thermal capacitance.
In order to meet the required control objectives, the temperature data must be provided to the operators at a sufficient rate to allow anticipatory changes in
. control output. For the zone temperature controllers themselves, this rate is determined by the controller, and is for all practical purposes continuous. The TAR 1/12/96 1.5-15
Qperatprs will not need data continuously sampled in this manner, since it takes a finite amount of time to interpret and respond to changes in RV temperature. To provide adequate control feedback to the operators, the DAS will scan at a rate of once every 2 minutes.
The allowable uncertainty of the temperature measurement instrumentation is also limited by control issues. In order to assure compliance with the allowable annealing operating conditions described in Section 1.8, the conditions specified in the written annealing procedures must be further limited to the extent that the instrument readings have uncertainty associated with them. If the uncertainty of the instruments is too large, this can result in procedural limits for the anneal that are unattainable. For this reason, based on the conditions specified in Section 1.8 and the known capabilities of the heating system, the allowable uncertainty of the temperature measurement instrumentation on the reactor vessel inside (zones E, F, K, M, N and L) will be limited to 25°F. The allowable uncertainty of the temperature measurement instrumentation on the RV outside beltline mid-region (zone C) will be further limited to 15°F.
TAR 1 /12/96 1.5-16
Number of Total Zone Zone Number Location Description Backup Number Description of Sensors at of Locations Each Sensors Location E
Nozzle -
6 Located inside bottom of 1
12 Bottom nozzles near PCS piping interface.
F Nozzle -
6 Located inside top of 1
12 Top nozzles near PCS piping interface.
K Reactor Vessel 30 Six columns of sensors; 1
60 Shell -
Each column contains Annealing sensors at five elevations Zone within the annealing zone.
M Reactor Vessel 12 Locations set 30° apart 1
24 Shell - Above oriented with and the Annealing between the RV nozzle Zone centerlines in the upper guard zone region below the nozzles.
N Reactor Vessel 6
Locations set 60° apart 1
12 Shell - Below within the lower guard the Annealing zone.
Zone L
Reactor Vessel 12 Six sensors in the flange 1
24 Shell - Above region and six in the the Nozzles region adjacent to and above the RV nozzle centerlines set 60° apart.
Total 72 144 Table 1.5.B-1 Internal Temperature Measurement Locations and Number of Sensors for Palisades Reactor Vessel Annealing TAR1/12/96 1.5-17
Zone A
B c
D G
H J
Total Note:
Number-of Tot_al Zone Number Location Description Backup Number Description :=
of Sensors at of Locations Each Sensors Location Reactor 3
Locations set 1 20° apart 1
6 Vessel Bottom and near the core support
- Flow Skirt lug elevation (i.e. 30°, 150°,270°).
Reactor 3
Locations set 1 20° apart 1
6 Vessel and coincident with the Annealing bottom internal annealing Zone - Bottom zone instrument locations.
Reactor 3
Locations set 1 20° apart 1
6 Vessel and coincident with the Annealing middle internal annealing Zone - Middle zone instrument locations.
Reactor 3
Locations set 1 20° apart 1
6 Vessel and coincident with the Annealing upper internal annealing Zone - Top zone instrument locations.
RV Support 1
Located on RV support 1
2 Structure -
center structural steel Annealing surface.
Zone (Region 2)
Reactor Cavity 21 Located on liner plate at 1
4 Steel Liner -
approximate midpoint of Annealing annealing zone and near Zone the bottom of Region 2.
(Region 2)
Reactor Cavity 21 Locations set adjacent to 1
4 Steel Liner -
nozzle penetrations on (Region 3) liner plate in Region 3.
17 34 1.
Both zone H devices positioned as close to the same azimuthal angle as one of the zone J devices as practical.
Table 1.'5.B-2 External Temperature Measurement Locations and Number of Sensors for Palisades Reactor Vessel Annealing TAR1/12/96 1.5-18
Zone Zone Number Location Description Number of Total Description of Backup Number Locations Sensors at of Each Sensors Location A
Reactor 1
Located ~s allowed by 1
2 Vessel -
the clearance between Bottom the vessel head and the reactor cavity floor insulation. (vertical)
I PCS Loop 6
Located on each PCS 0
18 Piping loop between SIG or pump and RV nozzle outside biological shield.
(3 directions)
Total 7
20 Table 1.5.B-3 External Displacement Measurement Locations and Number of Sensors for Palisades Reactor Vessel Annealing TAR1/12/96 1.5-19
Zone Zone Description Expected Uncertainty A
Reactor Vessel Bottom - Flow Skirt
< 20 °F B
Reactor Vessel Annealing Zone - Bottom
< 20 °F c
Reactor Vessel Annealing Zone - Middle
< 15 °F D
Reactor Vessel Annealing Zone - Top
< 20 °F G
RV Support Structure - Annealing Zone
. *< 20 °F (Region 2)
H Reactor Cavity Steel Liner - Annealing Zone
< 10 °F (Region 2)
J Reactor Cavity Steel Liner - (Region 3)
< 10 °F Table 1.5.C-1 External Temperature Measurement Uncertainty for Palisades Reactor Vessel Annealing TAR 1 /12/96 1.5-20
Zone Zone Description Expected Uncertainty A
Reactor Vessel - Bottom
< 0.1 inch I
PCS Loop Piping
< 0.05 inch Table 1.5.C-2 External Displacement Measurement Uncertainty for Palisades Reactor Vessel Annealing TAR1/12/96 1.5-21
. INSIDE CONTAINMENT OUTSIDE CONTAINMENT x
a
~
D.
D. <
Ol Figure 1.5.A-1 TAR1/12/96 1 5' APP OX.
HEAT EXCHANGER INLET /OUTLET DUC1WORK Palisades Annealing Indirect Combustion Radiant Heating System Conceptual Overview
- 1. 5-22
OUTLET#1 INLET#1 INLET#Z OUTLETn2 INLET#3 INLET#4
_J 0*
60° 120*
180" 240° 300" Z
l.LJ I
I 90° I
I I
270° I
.360° 0
,--~~~~~~~~~-+-'~~~~I
~~~~~~--'-~~~~~~-!-~~~~l~~~~l~~~~--.-----::~11---,
N
- l::=..11-~~-*~~-e~~.... *~~-e--~-*~~~~~~*.... ~--~~~*~~~~~~.... ~
ZONE f_,
TYP.6 Fl.CS.
ZONE E:---....
TYP.6 Fl.CS.
ZONE M--
l.LJ z
0 N
T----*--------- -
132.00 ACTIVE FUEL HEIGHT l -----*-----------
---~--------------------
ZONE N--
THERMOCOUPLE LOCATION
\\\\ \\
\\I
~ * *
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\\I II.*
u II II Figure 1.5.B-1 Internal Instrumentation Arrangement for Palisades Reactor Vessel Annealing II t'-
111
- 1)
TAR1/12/96 1.5-23
REACTOR VESSEL DTYP T
3 PLACES cc:
CTYP 0
u Lo.I 3 PLACES
> -I-u
([
B TYP j_
3 PLACES A
TYP 3 PLACES TYPICAL SECTION NOTE: RV BOTTOM HEAD WILL BE INSULATED DURING ANNEALING INSULATED ACCESS PANELS OPEN DURING ANNEALING H
~
TEMPERATURE
~ t DISPLACEMENT Figure 1.5.B-2 Primary Equipment External and Nozzle Internal Instrumentation Arrangement for Palisades Reactor Vessel Annealing TAR 1 /12/96 1.5-24