RS-25-017, Application to Relocate Technical Specifications 3.3.7.2 to a Licensee-Controlled Document
| ML25218A263 | |
| Person / Time | |
|---|---|
| Site: | Quad Cities  |
| Issue date: | 08/07/2025 |
| From: | Steinman R Constellation Energy Generation |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| RS-25-017 | |
| Download: ML25218A263 (1) | |
Text
4300 Winfield Road Warrenville, IL 60555 630 657 2000 Office RS-25-017 10 CFR 50.90 August 6, 2025 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Quad Cities Nuclear Power Station, Units 1 and 2 Renewed Facility Operating License Nos. DPR-29 and DPR-30 NRC Docket Nos. 50-254 and 50-265
Subject:
Application to Relocate Technical Specification 3.3.7.2 to a Licensee-Controlled Document In accordance with 10 CFR 50.90, "Application for amendment of license, construction permit, or early site permit," Constellation Energy Generation, LLC (CEG), requests an amendment to the Renewed Facility Operating License Nos. DPR-29 and DPR-30 for Quad Cities Nuclear Power Station (QCNPS) Units 1 and 2. Specifically, CEG requests relocation of Technical Specification (TS) 3.3.7.2, "Mechanical Vacuum Pump Trip Instrumentation" to an appropriate licensee-controlled document for QCNPS Units 1 and 2. provides an evaluation of the proposed changes. Attachment 2 provides the existing TS pages that will be deleted in their entirety. Attachment 3 provides existing TS Bases pages marked to show the TS Bases pages that will also be deleted and are provided for information only.
CEG has concluded that the proposed change presents no significant hazards considerations under the standards set forth in 10 CFR 50.92, "Issuance of Amendment."
The proposed changes have been reviewed by QCNPS Plant Operations Review Committee in accordance with the requirements of the CEG Quality Assurance Program.
There are no regulatory commitments contained in this submittal.
CEG requests approval of the proposed amendments by June 5, 2026. Once approved, the amendments shall be implemented within 60 days.
In accordance with 10 CFR 50.91, "Notice for public comment; State consultation,"
paragraph (b), a copy of this application, with attachments, is being provided to the designated State Officials.
If you should have any questions regarding this submittal, please contact Jared Smith at 779-231-6155.
U.S. Nuclear Regulatory Commission August 6, 2025 Page 2 I declare under penalty of perjury that the foregoing is true and correct. Executed on the 6th day of August 2025.
Respectfully, Rebecca L. Steinman Sr. Manager Licensing Constellation Energy Generation, LLC Attachments:
- 1. Application to Relocate Technical Specification 3.3.7.2 to a Licensee-Controlled Document-Evaluation of Proposed Change
- 2. Markup of Quad Cities Technical Specifications Pages Proposed for Relocation
- 3. Markup of Quad Cities Technical Specifications Bases Pages - For Information Only cc:
NRC Regional Administrator - Region III NRC Senior Resident Inspector - Quad Cities Nuclear Power Station Illinois Emergency Management Agency - Division of Nuclear Safety
- Steinman, Rebecca Lee Digitally signed by Steinman, Rebecca Lee Date: 2025.08.06 12:53:13 -05'00'
ATTACHMENT 1 Application to Relocate Technical Specification 3.3.7.2 to a Licensee-Controlled Document-Evaluation of Proposed Change
Subject:
Application to Relocate Technical Specification 3.3.7.2 to a Licensee-Controlled Document 1.0
SUMMARY
DESCRIPTION................................................................................................. 1 2.0 DETAILED DESCRIPTION.................................................................................................. 1
3.0 TECHNICAL EVALUATION
................................................................................................. 1
4.0 REGULATORY EVALUATION
............................................................................................ 3 4.1 Applicable Regulatory Requirements...............................................................................................3 4.2 Precedent................................................................................................................. 3 4.3 No Significant Hazards Consideration.............................................................................................3 4.4 Conclusions.............................................................................................................. 5
5.0 ENVIRONMENTAL CONSIDERATION
.............................................................................. 5
6.0 REFERENCES
..................................................................................................................... 6
ATTACHMENT 1 Application to Relocate Technical Specification 3.3.7.2 to a Licensee-Controlled Document-Evaluation of Proposed Change 1
1.0
SUMMARY
DESCRIPTION In accordance with 10 CFR 50.90, "Application for amendment of license, construction permit, or early site permit," Constellation Energy Generation, LLC (CEG), requests an amendment to the Renewed Facility Operating License Nos. DPR-29 and DPR-30 for Quad Cities Nuclear Power Station (QCNPS), Units 1 and 2.
Specifically, CEG requests relocation of Technical Specification (TS) 3.3.7.2, "Mechanical Vacuum Pump Trip Instrumentation" to an appropriate licensee-controlled document for QCNPS Units 1 and 2.
2.0 DETAILED DESCRIPTION TS 3.3.7.2 was added as part of the amendment to eliminate the scram and isolation functions of the Main Steam Line Radiation Monitor from the QCNPS TS (Reference 6.1). At the time of that amendment, NEDO-31466 Supplement 1 (Reference 6.2) indicated that the Limiting Condition for Operation (LCO) was needed because tripping and isolation of the vacuum pump was necessary to conform with the licensing basis leak rate assumed for the radiological dose evaluation of the Control Rod Drop Accident (CRDA) and thus met Criterion 3 of 10 CFR 50.36(c)(2)(ii). As described in Section 3, this criterion is no longer applicable, allowing for relocation of the requirements from the TS to an appropriate licensee-controlled document.
The proposed relocation will facilitate future changes to these requirements using the 10 CFR 50.59 change evaluation process. No actual plant equipment will be affected by this change. The operational requirements of the Mechanical Vacuum Pump (MVP) are not relaxed, merely relocated. The Updated Final Safety Analysis Report (UFSAR) will be revised to describe the MVP isolation as not credited in the CRDA evaluation. The design and operational characteristics of the system are unchanged by this request. Administrative changes may be made to reference the Technical Requirements Manual (TRM) instead of referencing the TS.
See Attachment 2 for the specific TS pages proposed to be deleted from the TS and relocated to the TRM as a new section. The associated TS Bases will also be relocated to the TRM. provides this Bases markup showing the deletion and is provided for information only.
3.0 TECHNICAL EVALUATION
This change relocates the isolation requirements for the Main Condenser Mechanical Vacuum Pump (MVP) to the TRM. The Main Condenser MVP is a gaseous evacuation system used for establishing and maintaining the main condenser vacuum when steam to operate the air ejectors is not available. If a CRDA were to occur during MVP operation, any resulting fission product release from the reactor coolant would travel through the open Main Steam Isolation Valves (MSIVs) to the Main Condenser where the MVP would exhaust the fission products through the 310-foot chimney via the gland seal holdup piping. The purpose of isolating the MVP line is to limit the release of radioactivity from the Main Condenser.
The Offgas System continuously removes non-condensable gases from the Main Condenser by the Steam Jet Air Extractors (SJAEs) during plant operation. The offgas extracted from the Main
ATTACHMENT 1 Application to Relocate Technical Specification 3.3.7.2 to a Licensee-Controlled Document-Evaluation of Proposed Change 2
Condenser consists of activation gases, fission product gases, radiolytic hydrogen and oxygen, and condenser air in-leakage. The Offgas System is designed to reduce offgas radioactivity levels to permissible levels for release under all plant operational conditions.
Four gamma-sensitive instrumentation channels monitor the gross gamma radiation from the main steam lines (MSLs). The monitors are physically located immediately downstream of the outer isolation valves of the four main steam lines to provide immediate indication of gross radiation in the lines and to initiate automatic action to contain the radiation, or limit the release of radioactivity. When a significant increase in the MSL radiation level is detected, an alarm is generated in the main control room and trip signals are transmitted to the Main Condenser MVP to ensure containment of the radioactive material. The trip setpoint is based on detection of fission products released during the design basis CRDA.
The CRDA dose analysis is based on the Alternative Source Term methodology and calculates a total effective dose equivalent for comparison to the dose criteria of 10 CFR 50.67. While the original analysis credited MVP isolation upon detection of high radiation levels during a CRDA, the revised analysis does not credit MVP isolation. The release for the scenario with the MVP operating has been qualitatively re-evaluated to demonstrate that the resultant dose maintains significant margin to the regulatory limits. The re-evaluation determined that the MVP operation scenario is not the limiting scenario due to the MVP only operating when core thermal power (CTP) level is <5%, which minimizes source activity from the coolant to the condenser, thereby reducing the source term by a factor of 20 as compared to the main condenser leakage scenario with source term at 100% CTP. In addition, the MVP operates for a short interval (normally during startup for up to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />) as compared to the 24-hour release considered in the dose calculation for the Main Condenser leakage scenario. This analysis scenario results in maintaining significant margin to the dose criteria of 10 CFR 50.67.
General Electric's (GE's) Licensing Topical Report (LTR) NEDO-31400A, "Safety Evaluation for Eliminating the Boiling Water Reactor Main Steam Line Isolation Valve Closure Function and Scram Function of the Main Steam Line Radiation Monitor," dated October 1992 was previously used to eliminate the scram and isolation functions of the Main Steam Line Radiation Monitor from the QCNPS TS. This LTR was reviewed and approved by the U.S. NRC for this purpose as documented in a letter dated May 15, 1991. At the time of the previous QCNPS amendment, a new LCO related to the trip function for the MVP was added to the TS (Reference 6.1) consistent with NUREG-1433, Revision 1, "Standard Technical Specifications, General Electric Plants, BWR/4," dated April 1995.
10 CFR 50.36(c)(2)(ii) provides four criterion for what limiting conditions for operation need to be included in a plant's TS. Criterion 3, which was the reason TS 3.3.7.2 was originally added to the TS, states the following:
A structure, system, or component that is part of the primary success path and which functions or actuates to mitigate a design basis accident or transient that either assumes the failure of or presents a challenge to the integrity of a fission product barrier.
However, isolation of the MVP is not a "primary success path" to mitigate the CRDA. Specially, the dose analyses described above demonstrate that satisfying Criterion 3 of 10 CFR 50.36(c)(2)(ii) is no longer applicable since both the onsite and offsite dose
ATTACHMENT 1 Application to Relocate Technical Specification 3.3.7.2 to a Licensee-Controlled Document-Evaluation of Proposed Change 3
consequences remain within the regulatory limit, assuming no automatic MVP isolation function.
Additionally, there is no specific requirement in NUREG-1433, Revision 5 (Reference 6.3), for including MVP instrumentation and isolation in the TS. Therefore, it was determined that the MVP trip function does not meet the criterion described in 10 CFR 50.36(c)(2)(ii) for inclusion in the TS and CEG is requesting permission to relocate this LCO from QCNPS TS to the appropriate licensee-controlled document, which is the site's Technical Requirements Manual (TRM).
4.0 REGULATORY EVALUATION
4.1 Applicable Regulatory Requirements The proposed TS change is consistent with the current regulations. Conformance of the CRDA dose analysis to 10 CFR 50.67, "Alternative source term, will be maintained.
The MVP instrumentation LCO is not necessary to satisfy the criterion in 10 CFR 50.36(c)(2)(ii).
Specially, the dose analyses demonstrate that Criterion 3 is no longer applicable since both the onsite and offsite dose consequences remain within regulatory limits assuming no automatic MVP isolation. Since this requirement is being maintained in the TRM, CEG considers that appropriate measures remain in place to ensure that any radioactive material released from a gross fuel failure will be maintained in the Main Condenser and processed through the Offgas System.
4.2 Precedent The activities proposed in this TS change are the same as the requirements for the MVP relocation included in previously-approved Amendment Nos. 299 and 302 for Peach Bottom Atomic Power Station, Units 2 and 3. (Reference 6.4) 4.3 No Significant Hazards Consideration Constellation Energy Generation, LLC (CEG) requests relocation of Technical Specification (TS) 3.3.7.2, "Mechanical Vacuum Pump Trip Instrumentation" to an appropriate licensee-controlled document for Quad Cities Nuclear Power Station (QCNPS), Units 1 and 2.
CEG has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:
ATTACHMENT 1 Application to Relocate Technical Specification 3.3.7.2 to a Licensee-Controlled Document-Evaluation of Proposed Change 4
- 1.
Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?
Response: No The proposed change relocates the MVP instrumentation and isolation functions from the TS into the licensee-controlled TRM. Retaining the requirement in the TRM ensures that the appropriate measures and requirements are in place to contain any release of radioactive material in the Main Condenser and then processed through the Offgas System.
The proposed change does not introduce new equipment or new equipment operating modes. The proposed change does not increase system or component pressures, temperatures or flow rates for systems designed to prevent accidents or mitigate the consequences of an accident. There are no physical changes or modification to the MVP, so the MVP will continue to function as designed. Since these conditions do not change, the likelihood of failure or malfunction is not increased. As a result, the probability of an accident previously evaluated is not significantly increased. Additionally, the consequences of an accident previously evaluated (i.e., the Control Rod Drop Accident (CRDA)), have been treated consistent with the QCNPS licensing basis, which is based on Alternative Source Term (10 CFR 50.67). The consequences of the bounding CDRA scenario are unchanged and remain within the regulatory acceptance criterion.
Based on the above, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
- 2.
Does the proposed change create the possibility of a new or different kind of accident from any previously evaluated?
Response: No No new or different accidents result from the proposed change. The proposed change does not involve a change in the method of operation of plant structure, system, or component (SSC). The proposed change does not increase system or component pressures, temperatures, or flowrates. There is no new system component being installed, no construction of a new facility, and no performance of a new test or maintenance function. The MVP will continue to function as designed. Since these conditions do not change, the proposed changes will not create the possibility of a new or different kind of accident. Retaining requirements for the MVP in the TRM will ensure that appropriate measures and requirements are in place such that any release of radioactive material released from a gross fuel failure will be contained in the Main Condenser and processed through the Offgas System. The proposed changes are consistent with the revised safety analyses for a CRDA as described in this request.
Therefore, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
ATTACHMENT 1 Application to Relocate Technical Specification 3.3.7.2 to a Licensee-Controlled Document-Evaluation of Proposed Change 5
- 3.
Does the proposed change involve a significant reduction in a margin of safety?
Response: No Relocating the requirements for the MVP to the TRM will ensure that appropriate measures and requirements are in place such that any release of radioactive material from a gross fuel failure will be contained in the Main Condenser and processed through the Offgas System. Analyses performed consistent with the licensing basis, demonstrate that the resulting offsite dose consequences are being maintained within regulatory limits without crediting the MVP isolation function.
Therefore, the proposed change does not involve a significant reduction in a margin of safety.
Based on the above, CEG concludes that the proposed amendments present no significant hazards considerations under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of "no significant hazards consideration" is justified.
4.4 Conclusions In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commissions regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
5.0 ENVIRONMENTAL CONSIDERATION
The proposed amendments would relocate TS requirements associated with MVP Instrumentation to a licensee-controlled document. The proposed amendments would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement. However, the proposed amendments do not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluents that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, in accordance with 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.
ATTACHMENT 1 Application to Relocate Technical Specification 3.3.7.2 to a Licensee-Controlled Document-Evaluation of Proposed Change 6
6.0 REFERENCES
6.1 Letter from R.M. Krich (ComEd) to U.S. NRC, "Request for an Amendment to Technical Specifications for Elimination of Main Steam Line Radiation Monitor Isolation and Scram Functions," dated December 30, 1999 (ADAMS Accession No. ML003671473) 6.2 NEDO-31466, Supplement 1, "Technical Specification Screening Criteria Application and Risk Assessment," dated February 1990 (ADAMS Accession No. ML20012B227) 6.3 NUREG-1433, Revision 5, "Standard Technical Specifications, General Electric Plants, BWR/4," dated September 30, 2021 (ADAMS Accession No. ML21272A357) 6.4 Letter from Richard B. Ennis (NRC) to Bryan C. Hanson (Exelon Nuclear), Peach Bottom Atomic Power Station, Units 2 and 3 - Issuance of Amendments RE: Eliminate Main Steam Line Radiation Monitor Trip and Isolation Function dated July 28, 2015 (ADAMS Accession No. ML15167A456)
ATTACHMENT 2 Mark-up of Technical Specifications Pages Proposed for Relocation Quad Cities Nuclear Power Station, Units 1 and 2 Renewed Facility Operating License Nos. DPR-29 and DPR-30 NRC Docket Nos. 50-254 and 50-265 Markup of Technical Specifications Pages 3.3.7.2-1 3.3.7.2-2 3.3.7.2-3
Mechanical Vacuum Pump Trip Instrumentation 3.3.7.2 Quad Cities 1 and 2 3.3.7.2-1 Amendment No. 199/195 3.3 INSTRUMENTATION 3.3.7.2 Mechanical Vacuum Pump Trip Instrumentation LCO 3.3.7.2 Four channels of Main Steam Line RadiationHigh Function for the mechanical vacuum pump trip shall be OPERABLE.
APPLICABILITY:
MODES 1 and 2 with the mechanical vacuum pump in service and any main steam line not isolated.
ACTIONS
NOTE-------------------------------------
Separate Condition entry is allowed for each channel.
CONDITION REQUIRED ACTION COMPLETION TIME A.
One or more channels inoperable.
A.1 Restore channel to OPERABLE status.
OR A.2
NOTE--------
Not applicable if inoperable channel is the result of an inoperable mechanical vacuum pump breaker.
Place channel in trip.
12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 12 hours B.
Mechanical vacuum pump trip capability not maintained.
B.1 Restore trip capability.
1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> (continued)
Deleted
Mechanical Vacuum Pump Trip Instrumentation 3.3.7.2 Quad Cities 1 and 2 3.3.7.2-2 Amendment No. 199/195 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME C.
Required Action and associated Completion Time not met.
C.1 Isolate the mechanical vacuum pump.
OR C.2 Remove the mechanical vacuum pump breaker from service.
OR C.3 Isolate the main steam lines.
OR C.4 Be in MODE 3.
12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 12 hours 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> 12 hours
Mechanical Vacuum Pump Trip Instrumentation 3.3.7.2 Quad Cities 1 and 2 3.3.7.2-3 Amendment No. 248/243 SURVEILLANCE REQUIREMENTS
NOTE-------------------------------------
When a channel is placed in an inoperable status solely for performance of required Surveillances, entry into associated Conditions and Required Actions may be delayed for up to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> provided mechanical vacuum pump trip capability is maintained.
SURVEILLANCE FREQUENCY SR 3.3.7.2.1 Perform CHANNEL CHECK.
In accordance with the Surveillance Frequency Control Program SR 3.3.7.2.2 Perform CHANNEL FUNCTIONAL TEST.
In accordance with the Surveillance Frequency Control Program SR 3.3.7.2.3
NOTE------------------
Radiation detectors are excluded.
Perform CHANNEL CALIBRATION.
In accordance with the Surveillance Frequency Control Program SR 3.3.7.2.4 Perform CHANNEL CALIBRATION. The Allowable Value shall be 7700 mR/hr.
In accordance with the Surveillance Frequency Control Program SR 3.3.7.2.5 Perform LOGIC SYSTEM FUNCTIONAL TEST including mechanical vacuum pump breaker actuation.
In accordance with the Surveillance Frequency Control Program
ATTACHMENT 3 Markup of Technical Specifications Bases Pages Proposed for Relocation
- For Information Only -
Quad Cities Nuclear Power Station, Units 1 and 2 Renewed Facility Operating License Nos. DPR-29 and DPR-30 NRC Docket Nos. 50-254 and 50-265 Markup of Technical Specifications Bases Pages B 3.3.7.2-1 B 3.3.7.2-2 B 3.3.7.2-3 B 3.3.7.2-4 B 3.3.7.2-5 B 3.3.7.2-6 B 3.3.7.2-7 B 3.3.7.2-8
Mechanical Vacuum Pump Trip Instrumentation B 3.3.7.2 Quad Cities 1 and 2 B 3.3.7.2-1 Revision 0 B 3.3 INSTRUMENTATION B 3.3.7.2 Mechanical Vacuum Pump Trip Instrumentation BASES BACKGROUND The Mechanical Vacuum Pump Trip Instrumentation initiates a trip of the main condenser mechanical vacuum pump breaker following events in which main steam line radiation exceeds predetermined values. Tripping the mechanical vacuum pump limits the offsite and control room doses in the event of a control rod drop accident (CRDA).
The Mechanical Vacuum Pump Trip Instrumentation (Refs. 1 and 2) includes detectors, monitors, and relays that are necessary to cause initiation of a mechanical vacuum pump trip. The channels include electronic equipment that compares measured input signals with pre-established setpoints. When the setpoint is exceeded, the channel output relay actuates, which then outputs an isolation signal to the mechanical vacuum pump trip logic.
The trip logic consists of two independent trip systems, with two channels of Main Steam Line RadiationHigh in each trip system. Each trip system is a one-out-of-two logic for this Function. Thus, either channel of Main Steam Line RadiationHigh in each trip system is needed to trip a trip system. The outputs of the channels in a trip system are combined in a one-out-of-two taken twice logic so that both trip systems must trip to result in a pump trip signal.
APPLICABLE The Mechanical Vacuum Pump Trip Instrumentation is assumed SAFETY ANALYSES in the safety analysis for the CRDA. The Mechanical Vacuum Pump Trip Instrumentation initiates a trip of the mechanical vacuum pump to limit offsite and control room doses resulting from fuel cladding failure in a CRDA (Ref. 3)
The mechanical vacuum pump trip instrumentation satisfies Criterion 3 of 10 CFR 50.36(c)(2)(ii).
(continued)
Deleted
Mechanical Vacuum Pump Trip Instrumentation B 3.3.7.2 Quad Cities 1 and 2 B 3.3.7.2-2 Revision 0 BASES (continued)
LCO The OPERABILITY of the mechanical vacuum pump trip is dependent on the OPERABILITY of the individual Main Steam Line RadiationHigh instrumentation channels, which must have a required number of OPERABLE channels in each trip system, with their setpoints within the specified Allowable Value of SR 3.3.7.2.4. The actual setpoint is calibrated consistent with applicable setpoint methodology assumptions.
Channel OPERABILITY also includes the mechanical vacuum pump breaker.
An Allowable Value is specified for the Main Steam Line RadiationHigh Trip Function specified in the LCO. The nominal trip setpoint is specified in the setpoint calculations. The nominal setpoint is selected to ensure that the setpoint does not exceed the Allowable Value between CHANNEL CALIBRATIONS. Operation with a trip setpoint less conservative than the nominal trip setpoint, but within its Allowable Value, is acceptable. A channel is inoperable if its actual trip setpoint is not within its required Allowable Value. The trip setpoint is that predetermined value of output at which an action should take place. The setpoint is compared to the actual process parameter (i.e., main steam line radiation) and when the measured output value of the process parameter exceeds the setpoint, the associated device (e.g., trip auxiliary unit) changes state. The analytic limit is derived from the limiting value of the process parameter obtained from the safety analysis. The trip setpoints are determined from the analytic limits, corrected for defined process, calibration, and instrument errors. The Allowable Values are then determined, based on the trip setpoint values, by accounting for the calibration based errors. These calibration based errors are limited to reference accuracy, instrument drift, errors associated with measurement and test equipment, and calibration tolerance of loop components. The trip setpoints and Allowable Values determined in this manner provide adequate protection because instrument uncertainties, process effects, calibration tolerances, instrument drift, and severe environment errors (for channels that must function in harsh environments as defined by 10 CFR 50.49) are accounted for and appropriately applied for the instrumentation.
(continued)
Mechanical Vacuum Pump Trip Instrumentation B 3.3.7.2 Quad Cities 1 and 2 B 3.3.7.2-3 Revision 0 BASES (continued)
APPLICABILITY The mechanical vacuum pump trip is required to be OPERABLE in MODES 1 and 2, when any mechanical vacuum pump is in service (i.e., taking a suction on the main condenser) and any main steam line not isolated, to mitigate the consequences of a postulated CRDA. In this condition fission products released during a CRDA could be discharged directly to the environment. Therefore, the mechanical trip is necessary to assure conformance with the radiological evaluation of the CRDA. In MODE 3, 4 or 5 the consequences of a control rod drop are insignificant, and are not expected to result in any fuel damage or fission product releases. When the mechanical vacuum pump is not in service or the main steam lines are isolated, fission product releases via this pathway would not occur.
ACTIONS A Note has been provided to modify the ACTIONS related to Mechanical Vacuum Pump Trip Instrumentation channels.
Section 1.3, Completion Times, specifies that once a Condition has been entered, subsequent divisions, subsystems, components, or variables expressed in the Condition, discovered to be inoperable or not within limits, will not result in separate entry into the Condition.
Section 1.3 also specifies that Required Actions of the Condition continue to apply for each additional failure, with Completion Times based on initial entry into the Condition. However, the Required Actions for inoperable Mechanical Vacuum Pump Trip Instrumentation channels provide appropriate compensatory measures for separate inoperable channels. As such, a Note has been provided that allows separate Condition entry for each inoperable Mechanical Vacuum Pump Trip Instrumentation channel.
A.1 and A.2 With one or more channels inoperable, but with mechanical vacuum pump trip capability maintained (refer to Required Action B.1 Bases), the Mechanical Vacuum Pump Trip Instrumentation is capable of performing the intended function. However, the reliability and redundancy of the Mechanical Vacuum Pump Trip Instrumentation is reduced, such that a single failure in one of the remaining channels could (continued)
Mechanical Vacuum Pump Trip Instrumentation B 3.3.7.2 Quad Cities 1 and 2 B 3.3.7.2-4 Revision 0 BASES ACTIONS A.1 and A.2 (continued) result in the inability of the Mechanical Vacuum Pump Trip Instrumentation to perform the intended function.
Therefore, only a limited time is allowed to restore the inoperable channels to OPERABLE status. Because of the low probability of extensive numbers of inoperabilities affecting multiple channels, and the low probability of an event requiring the initiation of mechanical vacuum pump trip, 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> has been shown to be acceptable (Ref. 4) to permit restoration of any inoperable channel to OPERABLE status (Required Action A.1). Alternately, the inoperable channel, may be placed in trip (Required Action A.2), since this would conservatively compensate for the inoperability, restore capability to accommodate a single failure, and allow operation to continue. As noted, placing the channel in trip with no further restrictions is not allowed if the inoperable channel is the result of an inoperable mechanical vacuum pump breaker, since this may not adequately compensate for the inoperable breaker. If it is not desired to place the channel in trip (e.g., as in the case where placing the inoperable channel in trip would result in loss of condenser vacuum), or if the inoperable channel is the result of an inoperable breaker, Condition C must be entered and its Required Actions taken.
B.1 Condition B is intended to ensure that appropriate actions are taken if multiple, inoperable, untripped channels within the same trip system result in not maintaining mechanical vacuum pump trip capability. The mechanical vacuum pump trip capability is maintained when sufficient channels are OPERABLE or in trip such that the Mechanical Vacuum Pump Trip Instrumentation will generate a trip signal from a valid Main Steam Line RadiationHigh signal, and the mechanical vacuum pump breaker will open. This would require both trip systems to have one channel OPERABLE or in trip, and the mechanical vacuum pump breaker to be OPERABLE.
The Completion Time is intended to allow the operator time to evaluate and repair any discovered inoperabilities. The Completion Time is acceptable because it minimizes risk while allowing time for restoration or tripping of channels.
(continued)
Mechanical Vacuum Pump Trip Instrumentation B 3.3.7.2 Quad Cities 1 and 2 B 3.3.7.2-5 Revision 43 BASES ACTIONS C.1, C.2, C.3, and C.4 (continued)
With any Required Action and associated Completion Time not met, the plant must be brought to a MODE or other specified condition in which the LCO does not apply. To achieve this status, the plant must be brought to at least MODE 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> (Required Action C.4). Alternately, the mechanical vacuum pump may be removed from service since this performs the intended function of the instrumentation (Required Actions C.1 and C.2). An additional option is provided to isolate the main steam lines (Required Action C.3), which may allow operation to continue. Isolating the main steam lines effectively provides an equivalent level of protection by precluding fission product transport to the condenser.
The allowed Completion Time of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is reasonable, based on operating experience, to reach MODE 3 from full power conditions, or to remove the mechanical vacuum pump from service, or to isolate the main steam lines, in an orderly manner and without challenging plant systems.
SURVEILLANCE The Surveillances are modified by a Note to indicate that REQUIREMENTS when a channel is placed in an inoperable status solely for performance of required Surveillances, entry into the associated Conditions and Required Actions may be delayed for up to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> provided mechanical vacuum pump trip capability is maintained. Upon completion of the Surveillance, or expiration of the 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> allowance, the channel must be returned to OPERABLE status or the applicable Condition entered and Required Actions taken.
This Note is based on the reliability analysis (Ref. 4) assumption of the average time required to perform channel Surveillance. That analysis demonstrated that the 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> testing allowance does not significantly reduce the probability that the mechanical vacuum pump will trip when necessary.
SR 3.3.7.2.1 Performance of the CHANNEL CHECK ensures that a gross failure of instrumentation has not occurred. A CHANNEL CHECK is normally a comparison of the parameter (continued)
Mechanical Vacuum Pump Trip Instrumentation B 3.3.7.2 Quad Cities 1 and 2 B 3.3.7.2-6 Revision 43 BASES SURVEILLANCE SR 3.3.7.2.1 (continued)
REQUIREMENTS indicated on one channel to a similar parameter on other channels. It is based on the assumption that instrument channels monitoring the same parameter should read approximately the same value. Significant deviations between the instrument channels could be an indication of excessive instrument drift in one of the channels or something even more serious. A CHANNEL CHECK will detect gross channel failure; thus, it is key to verifying the instrumentation continues to operate properly between each CHANNEL CALIBRATION.
Agreement criteria are determined by the plant staff based on a combination of the channel instrument uncertainties, including indication and readability. If a channel is outside the criteria, it may be an indication that the instrument has drifted outside its limit.
The Surveillance Frequency is controlled under the Surveillance Frequency Control Program. The CHANNEL CHECK supplements less formal, but more frequent, checks of channels during normal operational use of the displays associated with the required channels of this LCO.
SR 3.3.7.2.2 A CHANNEL FUNCTIONAL TEST is performed on each required channel to ensure that the channel will perform the intended function. A successful test of the required contact(s) of a channel relay may be performed by the verification of the change of state of a single contact of the relay. This clarifies what is an acceptable CHANNEL FUNCTIONAL TEST of a relay. This is acceptable because all of the other required contacts of the relay are verified by other Technical Specifications and non-Technical Specifications tests at least once per refueling interval with applicable extensions. Any setpoint adjustment shall be consistent with the assumptions of the current plant specific setpoint methodology.
The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
(continued)
Mechanical Vacuum Pump Trip Instrumentation B 3.3.7.2 Quad Cities 1 and 2 B 3.3.7.2-7 Revision 43 BASES SURVEILLANCE SR 3.3.7.2.3 and SR 3.3.7.2.4 REQUIREMENTS (continued)
A CHANNEL CALIBRATION is a complete check of the instrument loop and the sensor. This test verifies the channel responds to the measured parameter within the necessary range and accuracy. CHANNEL CALIBRATION leaves the channel adjusted to account for instrument drifts between successive calibrations consistent with the plant specific setpoint methodology. A Note to SR 3.3.7.2.3 states that radiation detectors are excluded from CHANNEL CALIBRATION since they are calibrated in accordance with SR 3.3.7.2.4.
The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
SR 3.3.7.2.5 The LOGIC SYSTEM FUNCTIONAL TEST demonstrates the OPERABILITY of the required trip logic for a specific channel. The system functional test of the mechanical vacuum pump breaker is included as part of this Surveillance and overlaps the LOGIC SYSTEM FUNCTIONAL TEST to provide complete testing of the assumed safety function. Therefore, if a breaker or the isolation valve is incapable of operating, the associated instrument channel(s) would be inoperable.
The Surveillance Frequency is controlled under the Surveillance Frequency Control Program.
(continued)
Mechanical Vacuum Pump Trip Instrumentation B 3.3.7.2 Quad Cities 1 and 2 B 3.3.7.2-8 Revision 0 BASES (continued)
REFERENCES 1.
UFSAR, Section 7.3.2.2.2.
2.
UFSAR, Section 11.5.2.6.
3.
UFSAR, Section 15.4.10.
4.
NEDC-30851-P-A, "Supplement 2, "Technical Specifications Improvement Analysis for BWR Isolation Instrumentation Common to RPS and ECCS Instrumentation," March 1989.