Presentation on theme: "ISTOG RELIEF REQUEST COMMONALITY ASSESSMENT Prepared by: E. Cavey DTE-Fermi 2 Page 1 The GOAL of this effort was to identify any challenging compliance."— Presentation transcript:
ISTOG RELIEF REQUEST COMMONALITY ASSESSMENT Prepared by: E. Cavey DTE-Fermi 2 Page 1 The GOAL of this effort was to identify any challenging compliance issues where the NRC is typically approving relief and the problems / alternative methods are similar for multiple plants. It is hoped that this information may trigger effort by ISTOG, NRC or ASME to consider more generic resolutions. The PROCESS was to: Collect Relief Requests from as many plants as possible ( 34 plants responded) Review each Relief Request and develop a short overall RR description for each Tabulate all of the RR descriptions and group in broad categories Refine the categories until final groupings with strong similarities were identifed If anyone sees a RR description which they may want to consider for use at their plant thay can contact me and I will give them the names of individuals to contact at applicable plants.
PUMP RELIEF TOPICNo. of Plants Use of analog gauges where Full Scale > 3x typical reference values Typically the justification is that overall accuracy of the parameter will be better than the Code allowed +/-2%, usually by invoking tighter calibration acceptance criteria or low impact on calculated DP for INLPR gauges. 27 Quarterly testing w/o flow measurement (fixed flow, min flow paths) Typical justification is that the test paths are fixed and that pressure and vibration monitoring is adequate for identifying degradation. 23 Use of vibration with minimum sensitivity >1/3 speed on low RPM pumps Typical justification is that the un-monitored frequency range would not add much value due to lack of corresponding pump or motor discrete frequencies. Also the prohibitive purchase and calibration costs of ultra low range test equipment. 13 ISTOG RELIEF REQUEST COMMONALITY ASSESSMENT Prepared by: E. Cavey DTE-Fermi 2 Page 2
PUMP RELIEF TOPICNo. of Plants ISTOG RELIEF REQUEST COMMONALITY ASSESSMENT Prepared by: E. Cavey DTE-Fermi 2 Page 3 Various similar instrument-related issues including Use of tank level changes over time in lieu of flow measurement Relief from ISTB 3520 requirement for fully venting suction pressure gauges where >0.25% error could be introduced Various arguments to support use of vibration only, flow only or DP only during IST 10 Use of a reference and acceptance criteria curves vs single points Typically cite guidance in OMN-9 - A reference curve and associated criteria values will be used due to inability to modify flowrate in different configurations 9 Other miscellaneous issues including Relief to allow Gp. B style quarterly testing even though the pumps are classified as Gp. A Relief to perform IST at intervals like 6 months, 2years, etc based on risk importance or very high margins to design criteria Implementation of Risk Informed IST 8
PUMP RELIEF TOPICNo. of Plants ISTOG RELIEF REQUEST COMMONALITY ASSESSMENT Prepared by: E. Cavey DTE-Fermi 2 Page 4 Pumps/motors with high reference vibration - use of higher Alert criteria Typically the system noise level is so high that reference values are near or above the Code Alert limit of ips. Relief is to use a higher value, typically 0.400, as Alert limit. Justification often includes detailed spectrum analysis and independent technical expert reviews. 6 The use of Gp A testing in lieu of performing CPT Typically cites the use of modified Gp. A testing (with tighter instrumentation and/or criteria) or standard Gp. A testing with addition of periodic full spectrum vibration analysis 5 Use of digital instruments with reference values up to 90% of full scale Typically cites implementation of Code Case OMN-6 to allow for exceeding the basic code requirement of reference values being less than 70% of full scale 4
PUMP RELIEF TOPICNo. of Plants ISTOG RELIEF REQUEST COMMONALITY ASSESSMENT Prepared by: E. Cavey DTE-Fermi 2 Page 5 Use of analysis/rebaselining in lieu of mandated Increased Frequency Typically states that in lieu of the doubled frequency test requirements specified in ISTB-6200(a) an evaluation and analysis shall be performed per the guidelines provided in ISTB-6200(c). 4 Quarterly testing of pumps running in pairs Typically justifies performance of quarterly Gp. A testing in paired operation and biennial CPT with individual pumps. 4 Relief to mount vibration transducers in other locations due to housing designs Several plants have motor housings which do not allow for Code required vibration monitoring – equivalent mounting locations are justified 4 Relief to conduct CPT at flow values less than 80% of design Typical justification is that the linearity of the pump curve slope at the lower flow value is the same as at the 80% design flow point. 2
VALVE RELIEF TOPICNo. of Plants ISTOG RELIEF REQUEST COMMONALITY ASSESSMENT Prepared by: E. Cavey DTE-Fermi 2 Page 6 Miscellaneous other relief issues including Relief from periodic LLRT based on continuous monitoring of downstream temperature / pressure indicators Allowance for check valve quarterly functional testing in one direction and shutdown/RF frequency for other direction Relief from 2yr PIT testing requirement where PIT is done using LLRT – allow use of App. J Option B frequency for PIT Implementation of Code Case OMN-1 or CVCM 37 Relief to allow for testing to be done online versus only RFO Typically involves request to allow for some check valve disassembly/inspections to be performed online during system / component outages rather than only during refueling outages. 12 Use of Disassembly / Inspection during outages vs qtrly functional testing for check valves Typically requests allowance to perform grouped check valve disassembly/inspections in lieu of functional testing for select valves – where overall implementation of CVCM was not desired. 9
VALVE RELIEF TOPICNo. of Plants ISTOG RELIEF REQUEST COMMONALITY ASSESSMENT Prepared by: E. Cavey DTE-Fermi 2 Page 7 Relief to treat a series or parallel pair as one valve Consistent justification involving the lack of intermediate test connections and obligation to consider any failures against both valves – relief being applied to check valve functional testing and/or LLRTs 7 Relief to perform SRV testing differently than the very prescriptive Code language including Allow stroke testing performance with valve uncoupled Pilot valve tests conducted on slave main bodies Relief from I-1330(a) – allow 20% each cycle with all tested every 3 cycles 7 Relief from quarterly functional testing of manual valves Allowance to perform exercise testing once per cycle 7
VALVE RELIEF TOPICNo. of Plants ISTOG RELIEF REQUEST COMMONALITY ASSESSMENT Prepared by: E. Cavey DTE-Fermi 2 Page 8 Relief from standard stroke time testing on control valves Typically relief to perform operational checks and FST but no full stroke time testing because of logic controls, etc 6 Relief on EFCVs to test per TS frequency versus Code POV requirements General relief based on specific Tech Spec testing requirements which apply to Excess Flow Check Valves 5 Relief from Stroke Time testing due to lack of VPI Typically involves SOVs with no remote VPI or means locally to verify actual valve position – relief from stroke timing and PIT with alternatives such as acoustical monitoring or periodic disassembly / inspection. 4
VALVE RELIEF TOPICNo. of Plants ISTOG RELIEF REQUEST COMMONALITY ASSESSMENT Prepared by: E. Cavey DTE-Fermi 2 Page 9 Stroke time test of a ganged-group of valves Typically involves a group of SOVs operated by a single control switch with group verification based on the slowest valve 4 Relief from accumulator volume measurement for relief valves Relief from the prescriptive language in OM and citing the ASME 95 Code App. I b instead 4 Relief from individual valve test reqts - use of scram time testing per Tech Specs For Scram Inlet / Outlet valves – Code testing requires scram, relief to schedule testing per specific Tech Spec frequency requirements 3
ISTOG RELIEF REQUEST COMMONALITY ASSESSMENT Prepared by: E. Cavey DTE-Fermi 2 Page 10 QUESTIONS ??? IDEAS ???