ML051940205
| ML051940205 | |
| Person / Time | |
|---|---|
| Site: | Perry  |
| Issue date: | 07/05/2005 |
| From: | Richard Anderson FirstEnergy Nuclear Operating Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| PY-CEI/NRR-2853L | |
| Download: ML051940205 (29) | |
Text
PENOC I _ftft Perry Nuclear Power Plant 10 Center Road FirstEnergy Nuclear Operating Company Perry Ohio 44081 Richard Anderson 440-280-5579 Vice President-Nuclear Fax: 440-280-8029 July 5, 2005 PY-CEI/NRR-2853L United States Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555 Perry Nuclear Power Plant Docket No. 50-440 License Amendment Request Pursuant to 10CFR50.90: Revision of Technical Specification Surveillance Requirement 3.3.1.3.5 which Revises the Enabled Region for the Oscillation Power Range Monitors Ladies and Gentlemen:
Nuclear Regulatory Commission (NRC) review and approval of a license amendment for the Perry Nuclear Power Plant (PNPP) is requested. The proposed amendment would modify the existing Technical Specification (TS) 3.3.1.3, "Oscillation Power Range Monitor (OPRM)
Instrumentation," Surveillance Requirement (SR) 3.3.1.3.5. Specifically, the thermal power level at which the OPRMs are "not bypassed" (enabled to perform their design function) will be changed from > 28.6% rated thermal power to 2 23.8% rated thermal power.
Plant-specific stability calculations are now required as part of the resolution to several generic issues associated with OPRM operability. One of the outcomes from this resolution was a change in the OPRM enabled region of the power to flow map. The thermal power level for enabling the OPRMs for Cycle 10 became > 27.2% rated thermal power. Since the current TS SR requirement is > 28.6%, the new TS SR thermal power level value is considered a non-conservative TS. PNPP is currently requiring the OPRMs to be enabled at 2 23.8% thermal power level through administrative controls. These controls will remain in place until such time that this license amendment is approved (reference NRC Administrative Letter 98-10, "Dispositioning of Technical Specifications That Are Insufficient to Assure Plant Safety").
Approval of the license amendment is requested prior to June 30, 2006, with the amendment to be implemented within 90 days following its effective date.
- - 2 July 5, 2005 PY-CEI/NRR-2853L Page 2 of 2 There are no regulatory commitments included in this letter or its attachments. If you have questions or require additional information, please contact Mr. Henry L. Hegrat, FirstEnergy Nuclear Operating Company Fleet Licensing at (330) 315-6944.
Very truly yours Attachments:
- 1. Notarized FirstEnergy Nuclear Operating Company Affidavit
- 2. Description, Background, Technical Analysis, Regulatory Analysis, and Environmental Consideration for the Proposed Technical Specification Change
- 3. Significant Hazards Consideration
- 4. Technical Specification Pages Annotated with the Proposed Amendment
- 5. Marked-Up Technical Specification Bases Pages (For Information Only)
- 6. Final Technical Specification Pages (proposed changes incorporated) cc: NRC Project Manager NRC Resident Inspector NRC Region III State of Ohio
Attachment 1 PY-CEI/NRR-2853L Page 1 of 1 I, Richard Anderson, hereby affirm that (1) I am Vice President - Perry, of the FirstEnergy Nuclear Operating Company, (2) I am duly authorized to execute and file this certification as the duly authorized agent for the FirstEnergy Nuclear Operating Company, and (3) the statements set forth herein are true and correct to the best of my knowledge, information and belief.
Rchar nderson Subscribed to and affirmed before me, the 5.3 day of I I CwC 7 2 _ _ .
d l U-n aL-v ALi rr,. aoz
Attachment 2
' ' PY-CEI/NRR-2853L Page 1 of 5
1.0 DESCRIPTION
The proposed License Amendment Request, submitted for Nuclear Regulatory Commission (NRC) review and approval, modifies Technical Specification (TS) 3.3.1.3, "Oscillation Power Range Monitor (OPRM) Instrumentation," Surveillance Requirement (SR) 3.3.1.3.5. Specifically, the thermal power level at which the OPRMs are "not bypassed" (enabled to perform their design function) will be changed from > 28.6% rated thermal power to 2 23.8% rated thermal power. Since the Perry Nuclear Power Plant (PNPP) has incorporated the use of plant-specific/cycle-specific stability calculations to generate the OPRM setpoints, the rationale for the proposed change is to incorporate a bounding value for enabling the OPRMs within the Technical Specifications, such that the number of future Technical Specification changes to the "not bypassed" (enabled) value will be minimized.
2.0 PROPOSED TECHNICAL SPECIFICATION CHANGE Technical Specification (TS) 3.3.1.3, "Oscillation Power Range Monitor (OPRM)
Instrumentation," Surveillance Requirement (SR) 3.3.1.3.5 will be modified to indicate that the OPRMs will be enabled at Ž 23.8% rated thermal power.
3.0 BACKGROUND
Regulatory History Due to concerns about the possibility of power oscillations due to thermal-hydraulic instabilities in Boiling Water Reactors (BWRs), the Nuclear Regulatory Commission issued Generic Letter (GL) 86-02, "Technical Resolution of Generic Issue B Thermal Hydraulic Stability." The GL requested BWR licensees to examine each core reload and to impose operating limitations, as appropriate, to ensure compliance with 10CFR50, Appendix A, General Design Criteria (GDC) 10 and 12. GDC 10 requires that the reactor core be designed with appropriate margin to assure that specified acceptable fuel design limits will not be exceeded during any condition of normal operation, including the effects of anticipated operational occurrences. GDC 12 requires assurance that power oscillations which can result in conditions exceeding specified acceptable fuel design limits are either not possible or can be reliably and readily detected and suppressed.
On March 9,1988, LaSalle Unit 2 experienced a power oscillation event. As a result of the analysis of this event, the NRC staff issued Bulletin 88-07, "Power Oscillations in Boiling Water Reactors (BWRs)," and requested all BWR licensees to review the adequacy of procedures, operator training programs, and instrumentation with regard to the detection and mitigation of power oscillations. Additionally, the NRC staff requested the BWR Owners' Group (BWROG) to perform generic evaluations of BWR plant response to core thermal hydraulic instabilities. These evaluations resulted in the General Electric Company (GE) recommending stability "Interim Corrective Actions" (ICAs) in a November 1988 letter to BWR utilities. On December 30,1988, the NRC issued Bulletin 88-07, Supplement 1, approving the proposed BWROG/GE interim operating recommendations with some additional conditions applied. This bulletin also
Attachment 2 PY-CEI/NRR-2853L Page 2 of 5 discussed long-term corrective actions. Such corrective actions might include hardware modifications or additions to facilitate manual or automatic protective response to avoid neutron flux oscillations or to suppress oscillations should they occur.
In June 1991, the BWROG issued NEDO-31960, "BWR Owner's Group Long Term Stability Solutions Licensing Methodology," which documented proposed long-term solutions to the stability issue as well as methodologies that have been developed to support the design of these long-term solutions. Supplement 1 to NEDO-31960 was issued in March 1992 and contained final methodology details and additional information requested by the NRC. By a July 1993 letter from A. C. Thadani (NRC) to L. A. England (BWROG), the NRC transmitted its safety evaluation report approving NEDO-31960 and NEDO-31960, Supplement 1.
On August 15, 1992, Washington Nuclear Power Unit 2 (WNP-2) experienced power oscillations during startup. As a result of the WNP-2 event and additional industry experience, the BWROG updated the ICAs in June 1994 to provide improved guidance for response to potential stability events. On July 11, 1994, the NRC issued GL 94-02, "Long-Term Solutions and Upgrade of Interim Operating Recommendations for Thermal-Hydraulic Instabilities in Boiling Water Reactors." GL 94-02 required BWR licensees to strengthen plant procedures and training programs to ensure power oscillations are avoided or detected and suppressed. The GL went on to require licensees to provide a plan for long-term corrective actions, including the specifications of any modifications needed to ensure compliance with GDCs 10 and 12.
Therefore, since 1988, BWR licensees have been using the ICAs to ensure power oscillations are avoided or detected and suppressed.
Interim Corrective Actions The ICAs and the guidance for their implementation were based upon instability prevention. The ICAs relied heavily upon control room operator actions.
The ICAs defined three regions on the power to flow map. The three regions are the Scram Region, the Exit Region, and the Controlled Entry Region. The Scram Region is the portion of the power/flow map where the control room operators will initiate a reactor scram as a precautionary measure in order to ensure that an instability event not occur.
The remaining two regions essentially are increased awareness areas for control room operators indicating that plant conditions are approaching those conditions that may be conducive to creating instabilities. The operator actions for these areas are to exit the region; however, no scram is required.
The ICA regions were based on the fuel and core designs present in the late 1980s-early 1990s, operating strategies present at the time, early decay ratio calculations, and engineering judgement.
OPRM Design As stated earlier, the long-term corrective actions for the stability issue were plant design modifications that would ensure compliance with GDCs 10 and 12.
Attachment 2 PY-CEI/NRR-2853L
- Page 3 of 5 The bases for the stability modifications are contained in three NRC approved GE topical reports (refer to References 1 through 3). Summarizing, the topical reports describe three separate algorithms for detecting stability-related oscillations: the period-based detection algorithm, the amplitude-based algorithm, and the growth-rate algorithm. The stability system (for the remainder of this submittal, the term OPRM will be used) implements these algorithms in microprocessor based modules. These modules execute the algorithms based on Local Power Range Monitor (LPRM) inputs, and generate alarms and trips based on these calculations. The trips result in initiation signals being sent to the Reactor Protection System (RPS). Only the period-based detection algorithm is used in the safety analysis. Therefore, only the period-based detection algorithm is required for channel operability. The remaining algorithms provide defense in depth and additional protection against unanticipated oscillations.
The period-based detection algorithm detects a stability related oscillation based on the occurrence of a fixed number of consecutive LPRM signal period confirmations followed by the LPRM signal amplitude exceeding a specified setpoint. Upon detection of a stability-related oscillation, a trip is generated for that OPRM channel.
The PNPP OPRM System consists of 4 OPRM trip channels, each channel consisting of two OPRM modules. Each OPRM module receives input from LPRMs. Each OPRM module also receives inputs from the Neutron Monitoring System (NMS) Average Power Range Monitor (APRM) power and flow signals to automatically enable the trip function of the OPRM module in specific areas of the power to flow map. The OPRMs are arranged in a one out of two taken twice logic similar to the RPS logic. One OPRM trip channel in each RPS division must generate a RPS channel trip before a full reactor scram will occur.
Proposed License Amendment The subject of this license amendment request is the point at which the automatic enabling of the OPRMs occurs.
4.0 TECHNICAL ANALYSIS
The OPRM Enabled Region is the area on the power to flow map where, if an instability is detected, a scram signal will be automatically generated. The Enabled Region was sized to encompass the Scram, Controlled Entry, and Immediate Exit Regions as defined in the 1994 ICAs.
The criteria for development of this region was defined in NEDO-32465-A, "BWR Owners' Group Reactor Stability Detect and Suppress Licensing Basis Methodology and Reload Applications" (reference 3). The region was specified to be reactor power level greater than 30% of original rated thermal power and core flow less than 60% of the rated core flow. The bases for this region was documented in a GE letter entitled "Guidelines for Stability Option IlIl Enabled Region," (OG96-630-169), dated September 12, 1996.
Attachment 2 PY-CEI/NRR-2853L Page 4 of 5 The current PNPP Technical Specification Surveillance Requirement 3.3.1.3.5 states that the OPRMs are "not bypassed" (enabled) when thermal power is greater than 28.6%1 and Reactor Recirculation System drive flow is less than the value which corresponds to 60%
core flow. Since the APRMs measure Reactor Recirculation System drive flow and use it as an indication of core flow, the core flow setpoint is converted into a drive flow setpoint for use by the OPRMs.
With respect to the GE 10CFR21 issues associated with the OPRMs, the ICA regions experienced the same issues as the OPRM settings. There previously was no check in the core design process to ensure the assumptions used to set the ICA regions were not being exceeded. As fuel and core designs evolved and operating strategies changed, the margin of protection provided by the ICAs had decreased. In order to restore this margin, it was determined the ICA regions should be expanded.
Furthermore, core stability is very sensitive to the final feedwater temperature.
Operating within the OPRM Enabled Region (low flow and high power) with reduced feedwater temperatures, presents the greatest potential for instability. GE calculations have shown the ICA regions needed to be made larger to provide protection under these conditions. The OPRM Enabled Region also needs to be enlarged, accordingly.
GE has developed an analytical method, which can be used to expand the ICA and Enabled Regions. The methodology is called the Backup Stability Protection (BSP) analysis. The analysis is used to redraw the ICA regions on the power flow map. The BSP analysis uses plant-specific inputs to develop decay ratios. The decay ratios are then used to adjust the ICA regions in order to provide stability protection for conditions of reduced feedwater temperature. The BSP analysis also combines the original three ICA regions (the Scram Region, the Exit Region, and the Controlled Entry Region) into two regions, the Scram Region and the Controlled Entry Region. The operator actions in the two BSP regions are similar to those taken in the original ICA Scram and Controlled Entry Regions.
A PNPP-specific BSP analysis was performed. The BSP analysis indicates that the lowest thermal power level (when considering reduced feedwater temperatures) for the combined Controlled Entry / Exit Region is 27.2% rated thermal power. The BSP analysis results indicate that the highest core flow (when considering reduced feedwater temperatures) for the combined Controlled Entry / Exit Region is 55% rated core flow.
Based on the BSP analysis, the TS core flow setpoint (< 60% core flow) is conservative and does not require revision.
Due to the BSP analysis, the TS thermal power setpoint has to be adjusted. Though the BSP PNPP-specific analysis results indicate the power setpoint should be 27.2%, a value of 23.8% is being requested. This value results in the OPRMs being required to be enabled at the same point that they are required to be OPERABLE, and is XIn 2000 PNPP uprated to 105% of the original thermal power level. Therefore, the 30% power level value contained in NEDO-32465-A was required to be adjusted to account for the PNPP uprate.
30% + 105% = 28.6% which is the current PNPP TS value.
I Attachment 2
-. - PY-CEI/NRR-2853L Page 5 of 5 conservative to the BSP analysis. Additionally, since the stability analysis is performed on an operating cycle basis, the 23.8% setpoint should bound future calculated power setpoint values, thereby minimizing the need to request future Technical Specification changes to revise the setpoint.
As a result of the BSP analysis, the power setpoint currently specified in SR 3.3.1.3.5 is non-conservative. Therefore, PNPP is currently requiring the OPRMs to be enabled at
> 23.8% thermal power through administrative controls. These controls will remain in place until such time that this license amendment is approved (reference NRC Administrative Letter 98-10, "Dispositioning of Technical Specifications That Are Insufficient to Assure Plant Safety").
5.0 REGULATORY ANALYSIS
SIGNIFICANT HAZARDS CONSIDERATION The Significant Hazards Consideration for the proposed Technical Specification change is contained in Attachment 3.
6.0 ENVIRONMENTAL CONSIDERATION
The proposed Technical Specification change request was evaluated against the criteria of 10 CFR 51.22 for environmental considerations. The proposed change does not significantly increase individual or cumulative occupational radiation exposures, does not significantly change the types or significantly increase the amounts of effluents that may be released offsite, and as discussed in Attachment 3, does not involve a significant hazards consideration. Based on the foregoing, it has been concluded that the proposed Technical Specification change meets the criteria given in 10 CFR 51.22(c)(9) for a categorical exclusion from the requirement for an Environmental Impact Statement.
7.0 REFERENCES
- 1. NEDO-31960-A, November 1995, "BWR Owners' Group Long Term Stability Solutions Licensing Methodology."
- 2. NEDO-31960-A, Supplement 1, November 1995, "BWR Owners' Group Long Term Stability Solutions Licensing Methodology (Supplement 1)."
- 3. NEDO-32465-A, August 1996, "Reactor Stability Detect and Suppress Solutions Licensing Basis Methodology for Reload Applications."
- 4. BWROG-94078, June 6,1994, "BWR Owner's Group Guidelines for Stability Interim Corrective Action."
- 5. BWROG 96113, September 17,1996, "Guidelines for Stability Option IlIl "Enabled Region" (TAC M92882)."
- 6. OG 02-0119-260, July 17, 2002, "Backup Stability Protection (BSP) for Inoperable Option III Solution."
Attachment 3 PY-CEI/NRR-2853L Page 1 of 3 SIGNIFICANT HAZARDS CONSIDERATION The proposed amendment is requesting Nuclear Regulatory Commission review and approval of changes to the Perry Nuclear Power Plant (PNPP) Technical Specifications which would modify the existing Technical Specification (TS) 3.3.1.3, "Oscillation Power Range Monitor (OPRM) Instrumentation," Surveillance Requirement (SR) 3.3.1.3.5.
Specifically, the thermal power level at which the OPRMs are "not bypassed" (enabled) will be changed from > 28.6% rated thermal power to > 23.8% rated thermal power.
Plant-specific stability calculations are now required as part of the resolution of several generic issues associated with OPRM operability. One of the outcomes from this resolution was a change in the OPRM "not bypassed" (enabled) region of the power to flow map. The thermal power value for the OPRM enabled region is being revised to incorporate a bounding value for enabling the OPRMs, such that the number of future Technical Specification changes to the "enabled" thermal power level value will be minimized.
The standards used to arrive at a determination that a request for amendment involves no significant hazards considerations are included in the Nuclear Regulatory Commission's regulation, 10 CFR 50.92, which states that the operation of the facility in accordance with the proposed amendment would not: (1) involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) create the possibility of a new or different kind of accident from any previously evaluated; or (3) involve a significant reduction in a margin of safety.
The proposed amendment has been reviewed with respect to these three factors, and it has been determined that the proposed change does not involve a significant hazard because:
- 1. The proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
The proposed change involves the use of a revised thermal power level to establish the OPRM enabled region. The OPRM enabled region is that area on the power to flow map where the OPRM System is activated to detect and suppress potential instability events. If reactor operations result in entrance into this region and a core instability is detected, the OPRM System will automatically initiate a reactor scram.
The revised enabled region provides assurance that the requirements of 10CFR50, Appendix A, General Design Criteria 10 and 12 remain satisfied for current and future core designs. Though the initiation of instability events are dependent upon thermal power levels and core flows, the revision to the enabled region thermal power level value does not increase the possibility of such an event. Once the OPRMs are enabled, the OPRM System would still mitigate an instability event, if detected. The revised enabled region does not impact any OPRM detection or mitigation actions for instability events.
I
Attachment 3 PY-CEI/NRR-2853L Page 2 of 3 The OPRMs are designed to detect and suppress potential instability events. As such, the OPRMs are not credited to provide any type of detection or mitigation actions for transients or accidents described within the PNPP Updated Final Safety Analysis Report (USAR) other than instability events. Hence, revising the OPRMs enabled region will not impact the transients or accidents described within the PNPP Updated Final Safety Analysis Report (USAR) other than instability events.
Since the OPRMs will be enabled at a thermal power lower than analytically required, the potential for additional scrams exists. However, since the possibility of an instability event occurring in the range between the revised thermal power level and the analytical value is remote, the probability of an additional scram from occurring is not significantly increased.
Therefore, since no significant changes are being made to the plant or its design, the probability or the consequences of an accident have not increased over those previously evaluated.
- 2. The proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
The proposed change involves the use of a revised thermal power level to establish the OPRM enabled region. The use of a revised thermal power level to establish the OPRM enabled region does not involve a physical modification to any plant system or component, including the fuel. The revised enabled region provides assurance that the requirements of 10CFR50, Appendix A, General Design Criteria 10 and 12 remain satisfied for current and future core designs. Though the initiation of instability events are dependent upon thermal power levels and core flows, the revision to the enabled region thermal power level value does not increase the possibility of such an event, or introduce any new or different events. Once the OPRMs are enabled, the OPRM System detects and mitigates an instability event if detected. The revised enabled region does not impact any mitigation actions.
Therefore, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
- 3. The proposed change does not involve a significant reduction in a margin of safety.
The proposed change involves the use of a revised thermal power level to establish the OPRM enabled region. Once the OPRMs are enabled, the OPRM System mitigates an instability event if detected. The revised enabled region does not impact any mitigation actions. The use of a revised thermal power level to establish the OPRM enabled region does not involve a physical modification to any plant system or component, including the fuel. The revised enabled region provides assurance that the requirements of 10CFR50, Appendix A, General Design Criteria 10 and 12 remain satisfied for current and future core designs. The revised enabled region restores the margin of protection provided by the OPRMs, which had been reduced as fuel and core designs have evolved since 1994. Therefore, the proposed change does not involve a significant reduction in a margin of safety.
Attachment 3 PY-CEI/NRR-2853L Page 3 of 3 Based upon the reasoning presented above, the requested change does not involve a significant hazards consideration.
Attachment 4 PY-CEI/NRR-2853L Page 1 of 3 TECHNICAL SPECIFICATION PAGES ANNOTATED WITH THE PROPOSED AMENDMENT
Attachment 4 PY-CEI/NRR-2853L Page 2 of 3 OPRM Instrumentation i l . :
3.3.1.3 3.3 INSTRUMENTATION 3.3.1.3 Oscillation Power Range Monitor (OPRM) Instrumentation LCO 3.3.1.3 Four channels of the OPRM Period Based Algorithm instrumentation shall be OPERABLE.
APPLICABILITY: THERMAL POWER > 23.8% RTP ACTIONS
----------------------NOTE-------------------------------------
Separate.Condition entry is allowed for each channel.
.CONDITION REQUIRED ACTION COMPLETION TIME A. One or more required A.1 Place channel in 30 days channels inoperable. trip.
OR A.2 Place associated RPS 30 days trip system in trip.
OR A.3 Initiate alternate 30 days method to: detect and.
suppress thermal -
.ydraulit instability oscillations.
B. OPRM trip capability B.1 Initiate alternate 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> not maintained. method to.detect and suppress thermal hydraulic instability*
oscillations.
C. Required Action and C.1 Reduce THERMAL POWER 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> associated Completion to < 23.8% RTP.
Time not met.
PERRY - UNIT 1 3.3-14a Amendment No.118
-Attachment 4 PY-CEI/NRR-2853L Page 3 of 3 OPRM Instrumentation 3.3.1.3 SURVEILLANCE REQUIREMENTS
NOTE-------------------------------------
When a channel is placed inan 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 the OPRM maintains trip capability.
SURVEILLANCE FREQUENCY SR 3.3.1.3.1. Perform CHANNEL FUNCTIONAL TEST. 184 days SR .3.3.1.3.2 Calibrate the local power range monitors. 1000 MWDIT average core exposure SR 3.3.1.3.3 ------------------ NOTE--------------------
-Neutron detectofr dre xclided&,
Perform CHANNEL CALIBRATION. 24 months I
SR 3.3 1.,.3.4 Perform . 24 months r SR 3.3.1.3.5 Veri OPR is'not bypassed when ERMAL-. 24 months POWE is -4;286tRTP and reci ati6h
- driv flow is.< the value co esponding to -60 of ted cor SR 3.3.1.3.6 ----------------- NOTE-------------I-----
Neutron detectors are excluded.
Verify the RPS RESPONSE TIME is within 24 months on a limits. STAGGERED TEST BASIS PERRY - UNIT I 3.3-14b Amendment No.118 I
Attachment 5 PY-CEI/NRR-2853L Page 1of 12 MARKED-UP TECHNICAL SPECIFICATION BASES PAGES (ForInformation Only)
Attachment 5 PY-CEI/NRR-2853L Page 2 of 12 OPRM Instrumentation B 3.3.1.3 B 3.3 INSTRUMENTATION B 3.3.1.3 Oscillation Power Range Monitor (OPRM) Instrumentation BASES BACKGROUND General Design Criterion 10 (GDC 10) requires the reactor core and associated coolant, control, and protection systems to be designed with appropriate margin to assure that acceptable fuel design limits are not exceeded during any condition of normal operation, including the effects of anticipated operational occurrences. Additionally, GDC 12 requires the -reactor core and associated coolant; control ;
and protection systems to be designed to assure that power oscillations which can result in conditions exceeding acceptable fuel design limits are either not possible or can
..he. r.liabiy..and-readiily.detected..and-suppressed-..The Oscillation Power Range Monitor (OPRM) System provides compliance with.GDC 10 and GDC 12, thereby providing protection from exceeding the fuel minimum critical power ratio (MCPR) Safety Limit.
References 1, 2. and 3 describe three separate algorithms
.. . . I for detecting stability related oscillations: the period based detectioln algorithm the amplitude based algorithm, arid'the growth rate algorithm. 'The OPRM System hardware implements these algorithms in .microprocessor based modules.
These modules execute the algorithms based on local power
- .range monitor (LPRM) inputs. and.generate alarms and trips based on these calculations... These trips result in tripping the Reactor Protection System (RPS) when the appropriate RPS trip logic is satisfied, as described in the Bases for LCO.3.3.1.1, "RPS Instrumentation." Only the period based detection algorithm is used ih the safety analysis (Ref. 1,
- 2. 6, and 7). Therefore, only the period based detection algorithm is 'required for channel OPERABILITY. The remaining algorithms provide defense in depth and additional protection against unanticipated oscillations.
(continued)
PERRY - UNIT 1 B 3.3-41a Revision No. 3-
Attachment 5 PY-CEI/NRR-2853L Page 3 of 12 OPRM Instrumentation B 3.3.1.3 BASES BACKGROUND The period based detection algorithm detects a (continued) stability related oscillation based on the occurrence of a fixed number of consecutive LPRM signal period confirmations followed by the LPRM signal amplitude exceeding a specified setpoint. Upon detection of a stability related oscillation, a trip isgenerated for that OPRM channel.
The OPRM System consists of 4 OPRM trip channels, each channel consisting of two OPRM modules. Each OPRM module receives input from LPRMs. Each OPRM module also receives input from the Neutron Monitoring System (NMS) average power
.range monitor (APRM) power and flow signals to automatically.
enable the trip function of the OPRM module in specific areas of the power to flow map.
Each OPRM module is continurmv y .. est ed.by...a.-self-test.
function. On detection' of any OPRM module failure, either a Trouble light or an INOP alarm are activated. Trouble indicates the OPRM module is still functioning but needs attention, while INOP indicates that the OPRM module may not be capable of meeting its functional requirements.
APPLICABLE It has been shown that BWR cbres-May ehilbit thermal-
- SAFETY ANALYSIS 'hydraulic reactor instabilities. Fn' high"poiwr'and low flow portions of the core power to flow operating domain. GDC 10 requires the reactor core and.associated coolant, control.
and protection systems to be designed with appropriate margin to assure that acceptable fuel design limits are not exceeded during any condition of normal operation, including the effects of anticipated operational occurrences. GDC 12 requires assurance-that power oscillations which can result in conditions exceeding acceptable fuel design limits are either not possible or can bereliably and readily detected and suppressed. The OPRM System provides compliance with
'GDC 10 and GDC 12 by detecting the onset of oscillations and suppressing them by initiating a react6r scram. This assures that the MCPR safety'limit will not be violated for anticipated oscillations.
(continued)
PERRY - UNIT 1 B '3.3-41b Revision No. 3
Attachment 5
. PY-CEI/NRR-2853L Page 4 of 12 OPRM Instrumentation B 3.3.1.3 BASES APPLICABLE The OPRM Instrumentation satisfies Criterion 3 of SAFETY ANALYSES 10 CFR 50.36(c)(2)(ii).
(continued)
LCO Four channels of the OPRM period based detection algorithm are required to be OPERABLE to ensure that stability related oscillations are detected and suppressed prior to exceeding the MCPR safety limit. Only one of the two OPRM modules period based detection algorithm is required for OPRM channel OPERABILITY. The highly redundant and low minimum number of required LPRMs in the OPRM cell design ensures that large numbers of cells will remain OPERABLE, even with large numbers of LPRMs bypassed.
APPLICABILITY The.OPRM instrumentation is required to be OPERABLE in order to detect and suppress neutron flux oscillations in-the
___=nt of thermal-hydraulic instability. AAszdescribed in
- Refe nc . 2. and.3,the,power/core flow region protected aga ist a nti ipated oscillations .isdefined by THERMAL POWER d/
RTP .nd'.r-ecir.cu'lation"dr.ive flow <'the';value correspondi ggto.60% of rated core'floW. The OPRM tripis d
b..be hs 'region, .and t abljed-`ih be leof enaling the trip function as a result of transients that place the core into that power/flow region.
Therefore, the OPRM is-required to be OPERABLE with THERMAL POWER >`23.8% RTP,.and at'all core flows while above that THERMAL POWER. It is.not necessary for the OPRM to be OPERABLE with THERMAL POWER < 23.8% RTP.because instabilities would not be expected to grow large enough-to threaten the MGPR 'Safety-Limit.-:This expectation is due, in part, to the large MCPR margin that exists at low power (Ref. 6).
(continued)
PERRY - UNIT 1 B 3.3-41c Revision No. 3
Attachment 5 PY-CEI/NRR-2853L Page 5 of 12 OPRM Instrumentation B 3.3.1.3 BASES (continued)
ACTIONS A Note has been provided to modify the ACTIONS related to the OPRM 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 OPRM 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 OPRM instrumentation channel.
A.1. A.2. and A.3 Because of the reliability and on-line self-testing of the OPRM instrumentation and the redundancy of the RPS design, an allowable out of service time.of 30 days has been shown to be acceptable.(Ref. 7) to permit restoration of any inoperable channel to OPERABLE status. However., this out of
..... service time is'only acceptable provided the OPRM .
.ihstrrmentdti6h stil1 maintains OPRM trip capabilityrefer to Required Action B.1). The remaining OPERABLE OPRM channels continue to provide trip capability (see Condition B) and provide operator information relative.to stability activity. The-remaining OPRM modules have high reliability.
With this high reliability, there is a low probability of a subsequent channel failure within the allowable out of service'time. .In addition,theOPRM modules continue-to perform on-line self-testing and alert the operator if any further system degradation occurs.
(continued)
PERRY - UNIT 1 B 3.3-41d Revision No. 3
Attachment 5 PY-CEI/NRR-2853L Page 6 of 12 OPRM Instrumentation B 3.3.1.3 BASES ACTIONS -A.1.-A.2. and A.3 (continued)
If the inoperable channel cannot be restored to OPERABLE status within the allowable out of service time, the OPRM channel or associated RPS trip system must be placed in the tripped condition per Required Actions A.1 and A.2. Placing the inoperable OPRM channel in trip (or the associated RPS
- trip system in trip) would conservatively compensate for the inoperability. restore capability to accommodate a single failure, and allow operation to continue. Alternately, if it is not desired to place the OPRM channiel (or RPS trip system) in trip (e.g.,.as in the case where placing the inoperable channel in trip would result in a full scram),
the alternate method of detecting and suppressing thermal-hydraulic instability oscillations, is required (Required
..... ctiD A' ... Jhi& alternate_.method. is .describedin ..
Reference 5. It consists of increased operator awareness and monitoring for neutron flux oscillations when operating in the region where oscillations are possible.. If indications of oscillation, as described in Reference 5. are observed by the operator, the operator will take the actions described by procedures, whichinclude initiating a manual scram of the reactor. ;
- B.1;-- . -...-.. ..
Required Action B.1 is intended to ensure that appropriate actions are taken if multiple, inoperable, untripped OPRM channels within the same RPS trip'.system result in not maintaining OPRM trip capability. The RPS logic is one-out-of-two taken twice. OPRM trip capability is considered to be maintained when sufficient..DPRSt channels are OPERABLE or in trip (or the associated RPS trip system is in trip), such that a valid OPRM signal will generate a trip signal in both RPS trip systems. This would require both RPS trip systems to have at least one OPRM channel OPERABLE or in trip (or the associated RPS trip system ih trip).
(continued)
PERRY - UNIT I B 3.3-41e Revision No. 3
a.
Attachment 5 PY-CEI/NRR-2853L Page 7 of 12 OPRM Instrumentation B 3.3.1.3 BASES ACTIONS B.1 (continued)
Because of the low-probability of the occurrence of an instability' 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> isan acceptable time to initiate the alternate method of detecting and suppressing thermal-hydraulic instability oscillations as described in the Bases for Action A.3 above. The alternate method of detecting and suppressing thermal-hydraulic instability oscillations would adequately address detection and mitigation in the event of instability oscillations. Based on industry operating experience with actual instability oscillations, the operator would be able to recognize instabilities during this time and take action to suppress them through a manual scram. Inaddition, the OPRM System may still be available to provide'alarms to the operator-if the onset of
.s.ioltions..er oe -to.Qcncur.....
-Since phrbn . peruation is.
i .
minimized in areas where oscillations may occur; operation without OPRM trip capability is considered acceptable with implementation of the alternate method of detecting and suppressing thermal-hydraulic instability oscillations, during the period when corrective actions are underway to.
resolve the inoperability that led to entry into Condition B. One reason this Condition .may be utilized isto provide time to implement-a software upgrade inthe plant ifa a. 4. z. . . .
- conmon cbuse-softare proble in 'itdentified.
C.1 With any Required Action and. associated Completion Time not met, THERMAL POWER must be reduced to < 23.8% RTP within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />. Reducing THERMAL POWER to < 23.8% RTP places the plant in a region where instabilities. are-notl1ikely to occur. The 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> is reasonable, based on operating experience, to reduce THERMAL POWER < 23.8% RTP from full powerlconditions in an orderly manner and without challenging plant systems.
(continued)
PERRY - UNIT 1B B 3.3-41f Revision No. 3
Attachment 5 PY-CEIINRR-2853L Page 8 of 12 OPRM Instrumentation 8 3.3.1.3 BASES (continued)
SURVEILLANCE For the following OPRM instrumentation surveillances, both REQUIREMENTS OPRM modules are tested, although only one is required to satisfy the surveillance requirement.
SR 3.3.1.3.1 A CHANNEL FUNCTIONAL TEST is performed to ensure that the channel will perform the intended function. A Frequency of 184 days provides an acceptable level of system average availability over the Frequency and is based on the reliability of the channel-(Ref. 7).
SR 3.3.1.3.2 LPRM gain settings are determined from the local flux prnfiies-neasur-deby. the Tra-ersing.Jncore-.Pr-obe.-(T.IP) -.
System. This establishes the relative local flux profile for appropriate representative input to the OPRM System.
The 1000 MWD/T Frequency is-based on operating experience with LPRM sensitivity changes.
The CHANNEL CALIBRATION verifi-n the chahWel responds th.
meastured Pdafeft& \Vth'ir thW 'nscessa'ry range and accuracy.
CHANNEL'CALIBRATION leaves the channel adjusted to account for instrument drifts between.successive calibrations.
Calibration of the channel provides a check of the internal reference voltage and the internal processor clock frequency. Since the OPRM is a digital system, the internal reference voltage and processor clock frequency are, in turn, used to automatically calibrate the-inte-r-nal-analog to digital converters. The calibration also.compares the desired trip setpoints with those in processor memory. The Allowable Values for the confirmation count setpoint (Np) and the amplitude trip setpoint.(S ) are specified in the Core Operating Limits Report'(COLR). As noted. neutron detectors are (continued)
PERRY - UNIT 1 B 3.3-419 R Revision No. 3
Attachment 5 PY-CEI/NRR-2853L Page 9 of 12 OPRM Instrumentation B 3.3.1.3 BASES SURVEILLANCE SR 3.3.1.3.3 (continued)
REQUIREMENTS excluded from CHANNEL CALIBRATION because of the difficulty of simulating a meaningful signal. Changes in neutron detector sensitivity are compensated for by performing the 1000 MWD/T LPRM calibration using the TIPs (SR 3.3.1.3.2).
The Frequency of 24 months is based upon the assumption of the magnitude of equipment drift provided by the equipment supplier (Ref. 9).
SR 3.3.1.3.4 The LOGIC SYSTEM FUNCTIONAL TEST demonstrates the OPERABILITY of the required trip logic for a specific
.. . . . .. hmel .hefunctional -testing nL contrxfl..roDds. in LCO .
3.1.3. PControl Rod OPERABILITY," and scram discharge volume (SDV) vent and drain valves in LCO 3.1.8. "Scram Discharge Volume (SDV) Vent and Drain Valves." overlaps this Surveillance to provide-complete testing of the assumed safety function. The OPRM self-test function may be utilized to perform this testing for those components that it is designed to monitor.
The 24-month-Frequency is based-on enginedri rg judgment. . -
high reliability of the components.-and operating experience..
_s-SR-ens es that trips.Initiated.from the:OPRM System' A
wi.l n.. b ot,be.i dadvertel y. ipass'ed';.h'en THERMALPOWERis..
at E;846S RTP a d recirculationxdrive flow is < the value correspond to 60X of rated-core flow.' '
(continued)
PERRY - UNIT 1 B 3.3-41h
-es .Revision No.
N 3
Attachment 5 .
PY-CEI/NRR-2853L Page 10 of 12 OPRM Instrumentation B 3.3.1.3 BASES SURVEILLANCE SR 3.3.1.3.5 (continued)
REQUIREMENTS 1 invo erification of the OPRM bypass
,--function, by ensurn thA OPRM modules are enabled when the APRM input is 2&k6t R and the recirculation drive flow u isE < 3e valueorresponding
°--- to 60% of rated core flow. The A recirculation drive flow inputs are by surveillances intheir respective.Technical Specifications. Because the enabled region conservatively bounds the region where instabilities are actually expected, the above nominal values of powe low a e-uti i for the bypass setpoints, without er al owance for inst ument drift or uncertainty.
If any bypass channel point s nonconservati (i.e., the
.. OPRM moduleiis byass dat RTP3iLan - . ..cicul atl.....
drive flow < the valu N.rjor dirg,.
..te 0%of rated core flow), then-the affected-PRM mo-dule is considered inoperable. Alternatively, the bypass channel can be placed t.
-inthe conservative condition (enabled). If placed in the' enabled condition, this SR ismet and the module is' considered OPERABLE.
The-Frequencyof:24 months isbased on engineering judgment, high reliabilit-yof-the-compogrents, and-operating .
experience.
SR 3.3.1.3.6 This SR ensures that the individual channel response times are less than or equal to the maximum values assumed in the accident.analysis (Ref. 10). .... ThePRM self-test function..
may be utilized to perform this testing for those components it is designed to monitor. The LPRM amplifier cards inputting-to the OPRM are excluded from the OPRM response time tdsting. The RPS RESPONSE TIME acceptance criteria are included in Reference 11.
(continued)
PERRY - UNIT 1 BR B 3.3-41i o No. 3 Revision
-Attachment 5 PY-CEI/NRR-2853L Page 11 of 12 OPRM Instrumentation B 3.3.1.3 BASES SURVEILLANCE SR 3.3.1.3.6 (continued)
REQUIREMENTS As noted. neutron detectors are excluded from RPS RESPONSE TIME testing because the principles of detector operation virtually ensure an instantaneous response time. RPS RESPONSE TIME tests are conducted on a 24 month STAGGERED TEST BASIS. This Frequency is based upon operating experience, which shows that random failures of instrumentation components causing serious time degradation, but not channel failure, are infrequent.
REFERENCES 1. NEDO-31960-A, "BWR Owners Group Long-Term Stability Solutions Licensing Methodology," November 1995.
- 2. NEDO 31960-A, Supplement 1,'"BWR Owners Group Long-Term Stability Solutions Licensing Methodology."
November 1995.
- 3. NRC Letter, A. Thadani to L. A. England. Acceptance for Referencing of Topical Reports NEDO:31960 and NEDO-31960 Supplement 1. BWR Own'ers Group Long-Term Stability Solutions Licensing Methodology',"
July 12. 1993.
- 4. Generic Letter 94-02, "Long-Term Solutions and Upgrade of Interim Operating Recommendations for Thermal-Hydraulic Instabilities in Boiling Water Reactors," July 11, 1994.
- 5. USAR Section 15B.4.4 Thermal and Hydraulic Design.
- 6. NEDO-32465-A, "BWR Owners'. Group Reactor Stability Detect and Suppress Solutions Licensing Basis Methodology and Reload Applications," August 1996.
- 7. CENPD-400-P-A, Rev 01, "Generic Topical Report for the ABB Option III Oscillation Power Range Monitor (OPRM)," May 1995.
(continued)
PERRY - UNIT BN B 3.3-41j, 'Revision No. 5
Attachment 5 PY-CEI/NRR-2853L Page 12 of 12 OPRM Instrumentation B 3.3.1.3 BASES REFERENCES 8. - NRC Letter, B. Boger to R. Pinelli, .'Acceptance of
.(continued) Licensing Topical Report CENPD-400-P, 'Generic Topical Report for the ABB Option III Oscillation Power Range Monitor'." August 16, 1995.
- 9. 00000-ICE-3230., "ABB Combustion Engineering Nuclear Operations, LTSSS Requirements Specification."
- 10. GENE-A13-00381-14. 'Licensing Basis Hot Bundle Oscillation Magnitude for Pe'rry' (latest approved revision).
- 11. USAR Table 7.2-3 'Reactor Protection System 'Response Time Table".
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PERRY - UNIT 1 BBko3.3-41k Revision No.' 3
- Attachment 6 PY-CEI/NRR-2853L FINAL TECHNICAL SPECIFICATION PAGES (PROPOSED CHANGES INCORPORATED)
Note, the final typed page does not include the Attachment header for ease of use.
WMINAT01%S RLW OPRM Instrumentation 3.3.1.3 3.3 INSTRUMENTATION 3.3.1.3 Oscillation Power Range Monitor (OPRM) Instrumentation LCO 3.3.1.3 Four channels of the OPRM Period Based Algorithm instrumentation shall be OPERABLE.
APPLICABILITY: THERMAL POWER 2 23.8% RTP ACTIONS
NOTE-------------------------------------
Separate Condition entry is allowed for each channel.
CONDITION REQUIRED ACTION COMPLETION TIME A. One or more required A.1 Place channel in 30 days channels inoperable. trip.
OR A.2 Place associated RPS 30 days trip system in trip.
OR A.3 Initiate alternate 30 days method to detect and suppress thermal hydraulic instability oscillations.
B. OPRM trip capability B.1 Initiate alternate 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> not maintained. method to detect and suppress thermal hydraulic instability oscillations.
C. Required Action and C.1 Reduce THERMAL POWER 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> associated Completion to < 23.8% RTP.
Time not met.
PERRY - UNIT 1 3.3-14a Amendment No. 118
i OPRM Instrumentation 3.3.1.3 SURVEILLANCE REQUIREMENTS
NOTE-------------------------------------
When a channel is placed ih 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 the OPRM maintains trip capability.
SURVEILLANCE FREQUENCY SR 3.3.1.3.1 Perform CHANNEL FUNCTIONAL TEST. 184 days SR 3.3.1.3.2 Calibrate the local power range monitors. 1000 MWD/T average core exposure SR 3.3.1.3.3 ------------------NOTE-------------------
Neutron detectors are excluded.
Perform CHANNEL CALIBRATION. 24 months SR 3.3.1.3.4 Perform LOGIC SYSTEM FUNCTIONAL TEST. 24 months SR 3.3.1.3.5 Verify OPRM is not bypassed when THERMAL 24 months POWER is 2 23.8% RTP and recirculation I drive flow is < the value corresponding to 60% of rated core flow.
SR 3.3.1.3.6 ------------------NOTE-------------------
Neutron detectors are excluded. -
Verify the RPS RESPONSE TIME is within 24 months on a limits. STAGGERED TEST BASIS PERRY - UNIT 1 3.3-14b Amendment No. I1