SVP-13-001, Summary Report of Completed Changes, Tests and Experiments for January 2011 - December 2012
| ML13024A429 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 01/04/2013 |
| From: | Hanley T Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation |
| References | |
| SVP-13-001 | |
| Download: ML13024A429 (6) | |
Text
Exelon Generation 10 CFR 50.59 10 CFR 72.48 SVP-13-001 January 4, 2013 U. S. Nuclear Regulatory Commisslon ATTN: Document Control Desk Washington, D.C. 20555 Quad Cities Nuclear Power Station, Units 1 and 2 Renewed Facility Operating License Nos. DPR-29 and DPR-30 NRC Docket Nos. 50-254,60-265, and 72-53
Reference:
Letter from W. R. Gideon (Exelon Generation Company, LLC) to U. S. NRC, "10 CFR 50.59 /10 CFR 72.48 Summary Report," dated January 5, 2011
Subject:
10 CFR 50.59 / 10 CFR 72.48 Summary Report In accordance with 10 CFR 60.59, subpart (d)(2), and 10 CFR 72.48 subpart (d)(2),
"Changes, tests, and experiments," Exelon Generation Company, LLC is submitting a summary of completed changes, tests, and experiments for Quad Cities Nuclear Power Station (QCNPS). This summary Is provided as an attachment to this letter, which describes the 10 CFR 50.59 evaluations that were completed for QCNPS between January 1, 2011 and December 31, 2012. The referenced letter provided the previous summary report. Note that there were no 10 CFR 72.48 evaluations completed for QCNPS during this time period.
Should you have any questions concerning this letter, please contact Mr. W. J. Beck at (309) 227-2800.
Tm H.tey Site V President Quad Cities Nuclear Power Station
Attachment:
Summary Report of Completed Changes, Tests, and Experiments.
cc: Regional Administrator - NRC Region III NRC Senior Resident Inspector - Quad Cities Nuclear Power Station ý1 "r~~5 I*,l, ogA e
ATTACHMENT Summary Report of Completed Changes, Tests, and Experiments 1- Tracking Number: QC-E-2011-001 Unit: Unit 1 / Unit 2 Activity Description The activity is a temporary change involving the installation and removal of four temporary jumpers in the Oscillation Power Range Monitor (OPRM) subsystem. This activity will bypass the Reactor Protection System (RPS) automatic suppression function for one RPS division, with the other RPS division in a tripped condition (i.e., half SCRAM). This configuration will exist while the RPS motor generator (MG) set is restored as the normal RPS power supply. This change is in response to an event at another station where a full RPS trip occurred during restoration of an RPS MG set when an OPRM RPS trip signal was received on the opposite trip system. This action is being taken as a compensatory action to prevent spurious/inadvertent RPS trips during RPS MG set removal/restoration/transfer operations.
Impact of Activity The installation of the jumpers requires use of the alternate method strategy for detection of thermal hydraulic instabilities. This method is described in the station updated Final Safety Analysis Report and Limiting Condition of Operation (LCO) action for Technical Specification LCO 3.3.1.3. The alternate method relies on operator action to prevent operation within the exclusion zone (greater than 25% reactor thermal power and core flow less than 60% of rated core flow), to detect oscillations and if necessary, to insert a reactor scram. Operator action is controlled by station operating procedures for power to flow map reactor operation. Design limits, accident frequencies, malfunctions, and consequences are unaffected by this change.
Basis for Not Requiring NRC Prior Approval A full 50.59 evaluation against the eight criteria of 10 CFR 50.59 was completed which concluded that prior NRC approval is not required. The proposed activity does not modify the NRC approved strategy for mitigating potential thermal hydraulic instabilities. By station procedures, and during this activity, operation of the plant is normally controlled outside of the exclusion zone where thermal hydraulic instability would be expected to occur. Alternate means of monitoring for this condition are invoked as prescribed in the licensing basis documents (including Technical Specifications) during the time the temporary jumpers are installed. In addition, although the jumpers are installed preventing the trip function for one RPS trip function, the OPRM System is still available to provide alarms to the operator if the onset of oscillations were to occur.
Page 1 of 5
ATTACHMENT Summary Report of Completed Changes, Tests, and Experiments 2 Tracking Number: QC-E-2011-002 Unit: Unit 1 / Unit 2 Activity Description This activity reviews the Control Room Habitability Analysis of Offsite Hazardous Chemicals (Calculation QDC-5700-M-1 767, Rev. 0). The purpose of this calculation is to document the triennial offsite survey of chemicals near Quad Cities and to evaluate the identified offsite toxic chemical hazards for control habitability. This calculation identified a new bounding scenario for control room habitability. The UFSAR currently states that a postulated failure of three large refrigerated atmospheric ammonia tanks located at an industrial site north of the nuclear plant is the basis for determining that adequate protection is provided for ammonia gas. As a result of the triennial offsite survey documented in the calculation, and resultant analysis for control room habitability, the new bounding scenario is a barge accident near the site carrying anhydrous ammonia or fertilizer. The bounding toxicity concentration limit for ammonia in the control room as stated in the UFSAR is being changed from 100 ppm to 300 ppm. This higher industry-accepted limit was used as the acceptance criteria for all the analyzed ammonia spills/accidents. This UFSAR update is required to reflect the more up-to-date identified release scenario and toxicity limit for ammonia.
Impact of Activity Currently, the UFSAR identifies the limiting scenario for control room habitability as an ammonia tank failure at an industrial site north of the plant. Based on the new toxic gas survey, the limiting scenario has become a barge accident near the plant. Based on this new scenario, no procedures or plant equipment is affected. The change of the ammonia control room toxicity limit stated in UFSAR section 6.4.4.2.3 from 100 ppm to 300 ppm has been endorsed through the NRC based on more recent studies, including Regulatory Guide 1.78 and NUREG/CR-6624. The higher main control room ammonia toxicity limit was used in the analysis for all postulated ammonia spills fixed and mobile off site and onsite that could adversely affect control room habitability.
Basis for Not Requiring NRC Prior Approval The 50.59 review concluded that the UFSAR change can be made without prior NRC approval.
The associated change in the allowable toxic gas concentration for ammonia (for control room habitability) increases from 100 ppm to 300 ppm. The increase in the allowable toxic gas concentration from 100 ppm to 300 ppm has been reviewed and accepted by the NRC. The new toxic gas release point increases the concentration of ammonia that the control room operators potentially can be exposed to; however, the analysis results of the spill concluded the exposure to control room personnel is within the acceptance criteria with use of the toxic gas analyzer system and isolation/recirculation function of the HVAC in its current configuration. The new limiting ammonia release source and higher concentration acceptance limit does not increase the likelihood of a failure of the toxic gas analyzers because the toxic gas analyzer is capable of monitoring and responding to the higher analyzed concentration in its current configuration with no decrease in reliability. It was concluded that the new limiting release source of the ammonia spill will not increase the frequency of the accident because the frequency of barge accidents based on published data was determined to be extremely low. The consequences of failure of the toxic gas monitoring system and HVAC isolation/recirculation functions is not increased, and a failure with a different result is not created because of the redundancy in the design of the toxic gas monitoring system and fail safe design of the HVAC isolation dampers. An accident of a different Page 2 of 5
ATTACHMENT Summary Report of Completed Changes, Tests, and Experiments type is not created because even though a new limiting source for the ammonia spill source has been determined, the accident remains the same: a chemical spill of ammonia within 5 miles of the plant. A toxic gas spill of ammonia will not adversely affect any physical plant fission product barriers. Therefore the design basis limits for a fission product barrier are not exceeded or altered. The methodology used in the evaluation has not changed from the method described in the UFSAR.
3] Tracking Number: QC-E-2012-001 Unit: Unit 2 Activity Description The proposed activity supports the placement of eight Westinghouse OPTIMA2 Low Tin ZIRLO Lead Test Assemblies (LTAs) in the core. Low Tin ZIRLO channels are dimensionally the same as the presently used channels. The difference is that the chemical composition of the material has slightly lower permissible concentrations of Tin, Iron, and Oxygen while having higher concentration of Niobium, and contains no Chromium or Nickel second phase precipitates, to improve channel bow performance relative to the licensed Zircaloy 2 channel material. The LTAs will be placed in the core such that the maximum thermal limits in the LTAs remain less than the maximum thermal limits observed over the entire duration of the cycle (i.e., non-limiting core regions). Low Tin ZIRLO offers an opportunity for improved fuel channel dimensional stability.
Impact of Activity The analysis of the LTAs concluded that NRC accepted design bases are met. The proposed activity does not physically alter any other equipment, system performance, or operator actions that could affect any of the accidents in UFSAR Section 15.0, "Accident Analyses". The proposed activity does not affect overall performance of any system that could more than minimally increase the frequency of occurrence of any accident. The proposed activity does not cause any SSC to be operated outside its design or testing limit, or change any SSC design function.
Basis for Not Requiring NRC Prior Approval The methodology for adopting an LTA program is described in CENPD-287-P-A. LTAs are permitted in Technical Specification 4.2.1, Fuel Assemblies, which states "Fuel assemblies shall be limited to those fuel designs that have been analyzed with NRC staff approved codes and methods and have been shown by tests or analyses to comply with all safety design bases. A limited number of lead test assemblies that have not completed representative testing may be placed in nonlimiting core regions." The proposed LTAs do not change the frequency of occurrence of an accident or malfunction evaluated in the UFSAR. The consequences of accidents evaluated in the UFSAR are not affected. No new accident or malfunction is created.
The LTAs were analyzed with applicable NRC approved codes and methods and have been shown to comply with the safety design bases. The LTAs will be placed in non-limiting core locations. Therefore, the proposed activities may be implemented without prior NRC approval.
Page 3 of 5
A1TACH MENT Summary Report of Completed Changes, Tests, and Experiments W4] Tracking Number: QC-E-2012-002 Unit: Unit 1 Activity Description This temporary change reroutes the Unit 1 Reactor Core Isolation Cooling (RCIC) steam supply condensate drain from its normal configuration (i.e., a common header with HPCI to the Main Condenser). A temporary hose for the RCIC Steam Line Condensate Drain will be routed to the Unit 1 Reactor Floor Drain Sump and discharge under the water level of the sump. The hose will be rated for at least 250 psig and 450 deg. F. The RCIC Steam Trap Bypass Valve (AO 1-1301-
- 32) will be maintained in the closed position for the duration of the hose installation. The high level drain pot alarm will not be defeated. The RCIC drain valve to the condenser (AO 1-1301-35) will also be maintained in the closed position during the duration of the installation to isolate the drain piping to the condenser. The RCIC Steam Header Inboard Drain Valve (AO 1-1301-34) will still automatically isolate the steam supply drain line to the condenser upon initiation of the RCIC system. This activity is being performed to allow the Unit I RCIC system to remain operable during repair of the High Pressure Coolant Injection (HPCI) drain valve AO 1-2301-30. The RCIC and HPCI Turbine Steam Supply Condensate Drain Lines tie together into a common header back to the Main Condenser.
Impact of Activity This temporary design change has a minimal impact on plant operations and the design bases of the system. The safety analyses described in the UFSAR are not affected. The rating of temporary components will exceed all maximum operating conditions for the temporary reroute of the condensate drain. UFSAR Section 5.4.6 states that the steam line drain bypass valves opens on high level in the drain pot. However, the RCIC Steam Trap Bypass Valve AO 1-1301-32 will be maintained in the closed position to ensure that the condensate will flow through the drain pot and steam trap during the time that this temporary change will be in place. This ensures that the condensate routed through the hose will not exceed the pressure-temperature rating of the hose and also ensures that excessive liquid does not enter the reactor building floor drain sump. The sump high level alarm function will not be defeated, so that the operators can take appropriate action if excessive condensate occurs.
Basis for Not Requiring NRC Prior Approval The evaluation concluded the temporary change does not adversely affect the reliability of the RCIC system or other mitigating systems available for use and that the fission product barriers would not be affected. There is no interaction with any initiators of an accident. The evaluation concluded that there was not more than a minimal increase in the frequency of an accident, in the likelihood of occurrence of a malfunction of an SSC, in the consequences of an accident, or the consequences of a malfunction of an SSC. The temporary change will not create the possibility of an accident of a different type or the possibility of a malfunction of an SSC with a different result.
The temporary change will not alter or change a design basis limit for a fission product barrier or result in a departure from the method of evaluation used in the safety analyses.
Page 4 of 5
ATTACHMENT Summary Report of Completed Changes, Tests, and Experiments 5] Tracking Number: QC-E-2012-003 Unit: Unit 1 Activity Description The proposed activity will add a new protective relaying scheme to isolate the Reserve Auxiliary Transformer 12 (RAT 12) upon detection of an open or loss of phase upstream of RAT 12. The new protective relaying scheme augments the existing protective devices which isolate RAT 12.
The new relay scheme monitors phase current input from existing Current Transformers on the high-voltage side of RAT 12 to detect an open or loss of phase condition, and on a detected open or loss of phase will initiate a transformer lockout. The open phase relay is provided with a short time delay allowing the detection scheme to differentiate between an open phase condition and a fault condition. This activity addresses a vulnerability identified during an event at Byron Station where a mechanical failure on the "C" phase to the Station Auxiliary Transformer (SAT) created a single phase voltage condition that propagated to the buses fed from the SAT.
Impact of Activity This activity will install a new relaying scheme to: (1) detect an open or loss of phase upstream of RAT 12, and (2) actuate the existing transformer lockout relays to isolate the transformer upon detection of an open or loss of phase condition. When RAT 12 is isolated, the feed to the associated 4kV buses will automatically be transferred to the Unit Auxiliary Transformer, if available. The actuation of the new scheme will produce the same results as the actuation of existing RAT 12 protection devices. The activity will protect the Class IE electrical system from an open or loss of phase condition. This protective scheme is a new; the initial installation of this activity will only alarm (the tripping action will not be armed). This approach allows an assessment of the functioning and response of the protective relaying scheme. After an appropriate time for assessment, the tripping function will be activated.
Basis for Not Requiring NRC Prior Approval The proposed activity does not adversely affect RAT 12 capacity or the existing automatic and manual switching capabilities involving the normal, reserve, or emergency feeds to the Station 4kV buses. The proposed activity does not adversely affect existing equipment protection, including protection from overcurrent, undervoltage, or degraded voltage conditions. There is no adverse impact on UFSAR-described design functions and the proposed activity will not adversely affect how the UFSAR functions are performed or controlled. However, the new trip system could result in a loss of offsite power to the 4kV buses on an open or loss of phase condition. The 50.59 review determined that due to the balancing of the positive effects (isolating a degraded power source) and the negligible negative effect (inappropriate isolation of a functioning power source), the proposed activity does not result in more than a minimal increase in the frequency of occurrence of an accident previously evaluated in the UFSAR. The activity does not involve an adverse change to an element of a UFSAR-described evaluation methodology, or use of an alternative methodology, that is used in establishing the design bases or used in the safety analyses. The proposed activity involves the installation of an additional feature that will disconnect an unreliable power supply to the 4kV buses. Therefore, the proposed activity does not involve a test or experiment not described in the UFSAR, where an SSC is utilized or controlled in a manner that is outside the reference bounds of the design.
Page 5 of 5