ML25321A747
| ML25321A747 | |
| Person / Time | |
|---|---|
| Site: | Columbia, Technical Specifications Task Force  |
| Issue date: | 09/25/2025 |
| From: | Technical Specifications Task Force |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| TSTF-606 | |
| Download: ML25321A747 (0) | |
Text
TSTF-606, Rev. 0 BWROG-151, Rev. 0 NUREGs Affected:
Revise the Actions Associated with an Inoperable Rod Worth Minimizer (RWM)
Technical Specifications Task Force Improved Standard Technical Specifications Change Traveler 1430 1431 1432 1433 1434 Classification: 1) Technical Change Recommended for CLIIP?: Yes Correction or Improvement:
Improvement NRC Fee Status:
Not Exempt Benefit:
Prevents Unnecessary Actions Changes Marked on ISTS Rev 5.0 PWROG RISD & PA (if applicable): N/A N/A Revision History Affected Technical Specifications OG Revision 0 Revision Status: Active Original Issue Revision
Description:
Revision Proposed by:
Columbia Owners Group Review Information Date Originated by OG:
06-Jun-25 Owners Group Comments (No Comments)
Date: 23-Jun-25 Owners Group Resolution:
Approved TSTF Review Information TSTF Received Date:
05-Sep-25 Date Distributed for Review 05-Sep-25 TSTF Comments:
A presubmittal discussion of the traveler was held with the NRC on August 7, 2025.
Date: 25-Sep-25 TSTF Resolution:
Approved Action 3.3.2.1.C NUREG(s)- 1433 Only Control Rod Block Instrumentation Action 3.3.2.1.C Bases NUREG(s)- 1433 Only Control Rod Block Instrumentation Action 3.3.2.1.D NUREG(s)- 1433 Only Deleted Change
Description:
Control Rod Block Instrumentation Action 3.3.2.1.D Bases NUREG(s)- 1433 Only Deleted Change
Description:
Control Rod Block Instrumentation 25-Sep-25 Copyright(C) 2025, EXCEL Services Corporation. Use by EXCEL Services associates, utility clients, and the U.S. Nuclear Regulatory Commission is granted. All other use without written permission is prohibited.
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TSTF-606, Rev. 0 BWROG-151, Rev. 0 Action 3.3.2.1.E NUREG(s)- 1433 Only Renamed E Change
Description:
Control Rod Block Instrumentation Action 3.3.2.1.E Bases NUREG(s)- 1433 Only Renamed E Change
Description:
Control Rod Block Instrumentation 25-Sep-25 Copyright(C) 2025, EXCEL Services Corporation. Use by EXCEL Services associates, utility clients, and the U.S. Nuclear Regulatory Commission is granted. All other use without written permission is prohibited.
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TSTF-606, Rev. 0 Page 1 Table of Contents Table of Contents..................................................................................................... 1
- 1.
SUMMARY
DESCRIPTION............................................................................................ 2
- 2.
DETAILED DESCRIPTION............................................................................................ 2 2.1.
System Design and Operation.................................................................................. 2 2.2.
Current Technical Specifications Requirements...................................................... 3 2.3.
Reason for the Proposed Change.............................................................................. 4 2.4.
Description of the Proposed Change........................................................................ 4
- 3.
TECHNICAL EVALUATION.......................................................................................... 5 3.1.
RWM is Not Credited in the Accident Analysis...................................................... 5 3.2.
Ensuring RWM is Available.................................................................................... 6 3.3.
Changes to Other Actions......................................................................................... 7
- 4.
REGULATORY EVALUATION..................................................................................... 8
- 5.
REFERENCES................................................................................................................... 9 Model Application DRAFT
TSTF-606, Rev. 0 Page 2
- 1.
SUMMARY
DESCRIPTION The proposed change revises the Technical Specifications (TS) Actions associated with an inoperable Rod Worth Minimizer (RWM). The proposed change affects the Boiling Water Reactor (BWR) standard Technical Specifications (TS) in NUREG-14331.
- 2.
DETAILED DESCRIPTION 2.1. System Design and Operation Control rods provide the primary means for control of reactivity changes. Control rod block instrumentation includes channel sensors, logic circuitry, switches, and relays that are designed to ensure that specified fuel design limits are not exceeded for postulated transients and accidents.
The TS 3.3.2.1, "Control Rod Block Instrumentation," requires the Rod Block Monitor (RBM),
the Reactor Mode Switch - Shutdown Position Function, and the Rod Worth Minimizer (RWM) to be operable.
- During Mode 1 operation, the RBM limits control rod withdrawal if localized neutron flux exceeds a predetermined setpoint during control rod manipulations. The RBM mitigates the consequences of a single control rod withdrawal event (RWE) when operating at greater than the low power setpoint. As a system assumed to mitigate an accident by preventing its occurrence, the RBM satisfies 10 CFR 50.36(c)(2)(ii) Criterion 3.
- When the Reactor Mode Switch is in the "Shutdown" position, a control rod withdrawal block is applied to all control rods to ensure that the shutdown condition is maintained. It prevents inadvertent criticality as the result of a control rod withdrawal during Mode 3 or 4, or during Mode 5 when the reactor mode switch is required to be in the shutdown position.
In these Modes, the core is assumed to be subcritical, and therefore, no positive reactivity insertion events are analyzed. As a system assumed to mitigate an accident by preventing its occurrence, the RBM satisfies 10 CFR 50.36(c)(2)(ii) Criterion 3.
- The RWM provides rod withdrawal and rod insertion block signals if the control rod movements ordered by the operator do not comply with the analyzed rod position sequence.
During low power operations, specific control rod sequences are designed to mitigate the consequences of the control rod drop accident (CRDA). The control rod sequences are called the Banked Position Withdrawal Sequence (BPWS) and are established in accordance with General Electric Topical Report NEDO-21231, "Banked Position Withdrawal Sequence (BPWS)," dated January 1977 (Reference 1) and NEDO-33091-A, Revision 2, "Improved BPWS Control Rod Insertion Process," dated July 2004 (Reference 2). The BPWS limits individual control rod worths so that, should a CRDA occur, the peak fuel enthalpy would 1 NUREG-1433 provides the standard TS for BWR/4 plant designs, but is also representative of the BWR/2, BWR/3, and, in this case, of the BWR/5 plant design.
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TSTF-606, Rev. 0 Page 3 remain below the specific energy design limit of 280 calories per gram (cal/gm). Beyond 280 cal/gm, fuel rod failure is assumed to occur2.
Licensees not utilizing the General Electric methodology have an equivalent rod sequence methodology that has been approved by the NRC. For example, Framatome topical report ANP 10333P-A, Revision 0, "AURORA B: An Evaluation Model for Boiling Water Reactors; Application to Control Rod Drop Accident (CRDA)," dated March 2018 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML18208A448), provides similar low power control rod sequences to mitigate a CRDA. For simplicity, the term "BPWS" is used while recognizing that other methodologies may use other names. The model application requires licensees that do not use the General Electric methodology to identify their approved methodology and to confirm that the traveler justification is applicable.
TS 3.1.6, "Rod Pattern Control," requires the operable control rods to comply with the requirements of the BPWS in Modes 1 and 2 with thermal power less than or equal to a plant-specific limit of approximately 10% RTP. These control rod patterns can be followed by the operator with or without the assistance of the RWM. TS 3.1.6 does not require the use of the RWM, and acknowledges that the RWM may be bypassed in accordance with TS 3.3.2.1. The requirements of TS 3.1.6 are not affected by the proposed change.
Plant procedures direct the operator to move control rods in accordance with the BPWS during reactor startup, shutdown, and low power level to comply with TS 3.1.6. The RWM function in TS 3.3.2.1 supplements the procedural controls and the operator by initiating rod withdrawal and rod insertion block signals if the control rod movements do not follow the BPWS.
The RWM does not interfere with normal reactor operation, does not affect any normal instrumentation displays associated with the selection of a control rod, and does not have any plant control functions. The RWM is a single-train, non-safety related system that will not function on a loss of offsite power. The RWM function is automatically bypassed at power levels greater than approximately 10% RTP. The RWM may be manually bypassed if procedural controls are implemented, including verification by a second licensed operator or qualified member of the technical staff that the first operator is performing control rod movements in accordance with the BPWS.
The control rods patterns required by LCO 3.1.6 are assumed to mitigate a CRDA.
Therefore, LCO 3.1.6 satisfies 10 CFR 50.36(c)(2)(ii) Criterion 3. The RWM is one method of ensuring that LCO 3.1.6 is met. Therefore, the RWM was determined to also satisfy 10 CFR 50.36(c)(2)(ii) Criterion 3.
2.2. Current Technical Specifications Requirements TS 3.3.2.1, "Control Rod Block Instrumentation," Table 3.3.2.1-1, states that the Rod Worth Minimizer Function is required to be operable in Modes 1 and 2 when thermal power [10]% RTP 2 NUREG-0800, "Standard Review Plan," Section 4.2, "Fuel System Design," Revision 2, July 1981.
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TSTF-606, Rev. 0 Page 4
[,except during the reactor shutdown process if the coupling of each withdrawn control rod has been confirmed]. Condition C applies when the RWM is inoperable during reactor startup. The Required Actions of Action C require either immediate suspension of control rod movement with the exception of a scram, or one of the following:
- Verification that at least 12 rods are withdrawn, and verification that movement of control rods is in compliance with the BPWS by a second licensed operator or other qualified member of the technical staff, OR
- Verification that startup with RWM inoperable has not been performed in the last calendar year, and that movement of control rods is in compliance with the BPWS by a second licensed operator or other qualified member of the technical staff.
Condition D is applicable when the RWM is inoperable during reactor shutdown. Required Action D.1 requires verification that movement of control rods is in compliance with the BPWS by a second licensed operator or other qualified member of the technical staff.
2.3. Reason for the Proposed Change The restriction on reactor startup with an inoperable RWM to once per calendar year is unnecessary. The RWM supplements the procedural controls and the operator to ensure the movement of control rods is in compliance with the BPWS as required by TS 3.1.6. The once-per-year constraint was included in the TS to ensure the RWM was maintained, which is now addressed by 10 CFR 50.65, the Maintenance Rule. In the event that RWM issues are experienced by a licensee, this constraint could prevent the startup of a reactor even though TS 3.1.6 can be met by the use of a second licensed operator or other qualified member of the technical staff verifying the control rod movements are in compliance with the BPWS.
Therefore, the proposed change retains the requirement for the RWM to be operable, but revises the Actions applicable when it is inoperable to be commensurate with its safety benefit.
2.4. Description of the Proposed Change The proposed change revises TS 3.3.2.1, Action C and D, Required Actions. The Action C Required Actions to suspend control rod movement except by scram, or to verify that at least 12 control rods are withdrawn, or to verify by administrative means that startup with RWM inoperable has not been performed in the last calendar year3, are removed. The Required Action to verify movement of control rods is in compliance with the BPWS by a second licensed operator or other qualified member of the technical staff during control rod movement is retained.
Under the proposed change, Action C, which applies when the RWM is inoperable during startup, and Action D, which applies when the RWM is inoperable during shutdown, will have the same 3 Some plant-specific Required Actions may state "in the last 12 months" instead of once per calendar year," and removal of such Required Actions is encompassed in this change.
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TSTF-606, Rev. 0 Page 5 Required Action. Therefore, to simplify the TS presentation, the two Actions are combined into a new Action C which applies when the RWM is inoperable.
The TS Bases are revised to reflect the change to the TS.
A model application is attached. The model should be used by licensees desiring to adopt the traveler following NRC approval.
- 3.
TECHNICAL EVALUATION 3.1. RWM is Not Credited in the Accident Analysis The proposed change to eliminate the restriction on reactor startups with the RWM inoperable to once per calendar year does not have an adverse effect on the accident analysis assumptions.
The rapid removal of a high worth control rod in a BWR under certain circumstances could result in a potentially significant power excursion and significant fuel damage. The Control Rod Drop Accident (CRDA) postulates the decoupling of a fully inserted control rod from its drive while remaining in the fully inserted position. The scenario then assumes that the dropping of the rod results in a high local reactivity in a small region of the core.
The Advisory Committee on Reactor Safeguards (ACRS) studied Generic Item IIA-2, "Control Rod Drop Accident (BWRs)," as documented in a \
letter dated June 1, 1976 (Reference 2). The document describes the series of events which must all occur to potentially cause fuel damage in a CRDA. Summarizing:
- A high worth control rod must become disconnected from the drive.
- The rod must stick in the upper quadrant of the core while the control rod drive is withdrawn by at least a third of the core height away from the stuck rod.
- The disconnect is not discovered and remedied.
- The stuck rod must drop when the reactor is nearly critical or less than 10% RTP.
- The stuck rod must drop when the withdrawn rod pattern enhances the worth of the stuck rod to near its maximum worth.
The ACRS study determined that a reasonable estimate of the probability of having a CRDA exceeding 280 cal/gm is about 10-12 per reactor year, without including any credit for the use of an RWM.
Regarding the RWM, the study stated:
A parallel question exists as to requirements (Tech Spec) for RWM operability. The analysis in this memo has essentially ignored any contribution of the RWM to the total probabilities. The results of the analyses in this memo do not seem to demand the 10-1 to 10-2 extra factor which could be achieved from the RWM. Nevertheless, it is a system which exists and which can be useful with relatively little effort. The extra factor which it introduces serves as an additional buffer for the [C]RDA and should not be ignored. It would seem to be particularly useful in assuring the correct rod patterns when entering the DRAFT
TSTF-606, Rev. 0 Page 6
[C]RDA region from the power region. Thus, it is recommended that Tech Spec requirements be maintained to assure a reasonable degree of operability.
In 1982, the Boiling Water Reactor Owners' Group (BWROG) proposed eliminating the CRDA from the standard General Electric BWR reload analysis as it was shown that, in all cases, the peak fuel enthalpy would be much less than the 280 cal/gm design limit (Reference 3). The RWM was not credited in the analysis. Removal of the CRDA from the standard reload analysis was found acceptable by the NRC in 1986 (Reference 4).
NRC Standard Review Plan, (Reference 5) Section 15.4.9, Appendix A, "Radiological Consequences of Control Rod Drop Accident (BWR)," states, "Based on past reviews by the staff, a control rod drop accident is expected to result in radiological consequences less than 10% of the Part 100 guideline values even with conservative assumptions."
One other event is prohibited by the RWM. A rod withdrawal error (RWE) at low power is caused by an inadvertent operator-initiated withdrawal of a single control rod from the core. The RWE is categorized as an infrequent accident and is not considered credible during reactor startup or during low power ranges. The probability of this event is low because, similar to the CRDA, the RWE accident is contingent on an operator, contrary to station procedures, selecting and withdrawing an out-of-sequence, high worth rod and disregarding of the continuous alarms. In the event the RWM is inoperable during reactor startup, the RWE event is also precluded by a second licensed operator or other qualified member of the technical staff verifying that control rod movement complies with the BPWS.
Therefore, the restriction on startups with the RWM inoperable to once per calendar year is not necessary to ensure that a CRDA or RWE remain of very low probability and consequence.
3.2. Ensuring RWM is Available The requirement to have an operable RWM was introduced during the development of the improved standard TS in the late 1980's. The RWM operability requirements were added to standard TS to provide a strong incentive for stations to maintain and improve the operability of the RWM because the Rod Sequence Control System requirements were removed from the standard TS. The addition of the RWM operability requirements was made to ensure a reasonable degree of availability of the RWM, as at the time this backup system was often poorly maintained and was frequently bypassed. However, the addition of these requirements preceded 10 CFR 50.65, "Requirements for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants," which requires that licensees monitor the performance or condition of certain components in a manner to provide reasonable assurance that the intended functions are fulfilled.
Although the RWM is a not a safety-related system, the ability to bypass the system is relied on in plant emergency operating procedures, and the all-rod full-in indication provided by the RWM is used to mitigate an Anticipated Transient Without Scram event. Both of these functions require monitoring per 10 CFR 50.65(a)(1). Therefore, the licensee's Maintenance Rule program provide reasonable assurance that the RWM will be maintained and will normally be operable.
The proposed change does not eliminate the requirement for the RWM to be operable. Failure of the TS Surveillance Requirements on the RWM would be entered into the licensee's Corrective DRAFT
TSTF-606, Rev. 0 Page 7 Action Program (CAP). Repeated failures require trending and actions to address the failures, which are in addition to the Maintenance Rule requirements.
In summary, limiting reactor startups with an inoperable RWM to once per calendar year is not necessary to ensure the system is maintained and will normally be operable. The TS requirement for the RWM to be operable and the TS Surveillance Requirements that verify its operability, as well as the licensee's CAP and Maintenance Rule program, are sufficient to ensure the RWM will normally be able to perform its function. However, should the RWM be inoperable, the required independent verification will ensure that the movement of control rods is in compliance with TS 3.1.6 and the BPWS.
3.3. Changes to Other Actions Existing TS 3.3.2.1, Required Action C.1, requires immediate suspension of control rod movement except by scram when the RWM is inoperable during startup. The Required Action is joined by a logical "OR" to the other Required Actions. Under the proposed change, this Required Action is no longer needed. The proposed Action requires verification that movement of control rods is in compliance with the BPWS by a second licensed operator or other qualified member of the technical staff during control rod movement. Rod motion associated with a reactor scram is also in compliance with the BPWS. Therefore, Required Action C.1 is not necessary.
Existing TS 3.3.2.1, Required Action C.2.1.1, permits a startup with an inoperable RWM if such as startup has not occurred in the last calendar year or if at least 12 control rods have been withdrawn. The basis for the 12 withdrawn control rods provision is given in NEDO-21231, Section 4.1, which states, "It has been determined, after extensive study and experience that after the first few control rods are withdrawn in a BPWS group the worth of the remaining control rods is very low." Therefore, after at least 12 control rods are withdrawn, the remaining control rods do not have sufficient worth to approach the design enthalpy limit in the event of a CRDA.
However, if the RWM is inoperable prior to withdrawing the first 12 rods and the option to start up with an inoperable RWM has been used in the last calendar year, the Actions effectively prevent a reactor startup. The retained Required Action to verify that movement of control rods is in compliance with the BPWS by a second licensed operator or other qualified member of the technical staff serves the same purpose as the limitation regarding 12 control rods by effectively preventing a CRDA that could approach the design enthalpy limit. Therefore, the option to rely on withdrawal of at least 12 control rods is not necessary and can be removed.
With the proposed changes, Condition C, "Rod worth minimizer (RWM) inoperable during reactor startup," and Condition D, "RWM inoperable during reactor shutdown," have the same Required Action and Completion Time. Therefore, the TS can be simplified by revising Condition C to state, "Rod worth minimizer (RWM) inoperable," and eliminating Action D.
Action E is renamed Action D. This is an editorial improvement to simplify the TS and does not affect the licensee requirements. When the RWM is inoperable, the only Required Action is to verify that movement of control rods is in compliance with the BPWS by a second licensed operator or other qualified member of the technical staff.
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TSTF-606, Rev. 0 Page 8 Summarizing, the proposed change revises the Actions applicable when the RWM is inoperable to ensure that control rod movement is in compliance with the BPWS. The change eliminates restrictions that were intended to assure the RWM is available by crediting licensee Maintenance Rule and Corrective Action Program requirements. Finally, the proposed change streamlines the TS Actions for an inoperable RWM as an operator aid.
- 4.
REGULATORY EVALUATION The regulation at Title 10 of the Code of Federal Regulations (10 CFR) Section 50.36(b) requires:
Each license authorizing operation of a utilization facility will include technical specifications. The technical specifications will be derived from the analyses and evaluation included in the safety analysis report, and amendments thereto, submitted pursuant to [10 CFR] 50.34 ["Contents of applications; technical information"]. The Commission may include such additional technical specifications as the Commission finds appropriate.
Regulation 10 CFR 50.36(c), Paragraph (2), states that when a limiting condition for operation of a nuclear reactor is not met, the licensee shall shut down the reactor or follow any remedial action permitted by the technical specifications until the condition can be met. The proposed change provides a remedial action to be taken when the limiting condition for operation is not met and complies with 10 CFR 50.36(c)(2).
Per 10 CFR 50.90, whenever a holder of a license desires to amend the license, application for an amendment must be filed with the Commission, fully describing the changes desired, and following as far as applicable, the form prescribed for original applications.
Per 10 CFR 50.92(a), in determining whether an amendment to a license will be issued to the applicant, the Commission will be guided by the considerations which govern the issuance of initial licenses to the extent applicable and appropriate.
Section IV, "The Commission Policy," of the "Final Policy Statement on Technical Specifications Improvements for Nuclear Power Reactors" (58FR39132), dated July 22, 1993, states in part that improved standard TS have been developed and will be maintained for each Nuclear Steam Supply System (NSSS) owners group. The Commission's policy encourages licensees to use the improved standard TS as the basis for plant-specific TS. The industry's proposal of travelers and the NRC's approval of travelers is the method used to maintain the standard TS as described in the Commission's policy. Following NRC approval, licensees adopt travelers into their plant-specific TS following the requirements of 10 CFR 50.90. Therefore, the traveler process facilitates the Commission's policy while satisfying the requirements of the applicable regulations.
The regulation at 10 CFR 50.36(a)(1) also requires the application to include a "summary statement of the bases or reasons for such specifications, other than those covering administrative controls." The proposed traveler revises the Bases to be consistent with the changes to the TS, and therefore complies with 10 CFR 50.36(a)(1).
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TSTF-606, Rev. 0 Page 9 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 approval of the proposed change will not be inimical to the common defense and security or to the health and safety of the public.
- 5.
REFERENCES
- 1. General Electric Topical Report NEDO-21231, "Banked Position Withdrawal Sequence,"
dated January 1977.
- 2. Letter and enclosure from B. C. Rusche (NRR) to R. Fraley (ACRS), "Generic Item IIA-2 Control Rod Drop Accident (BWRs)," dated June 1, 1976 (ADAMS Accession No. ML20125D471).
- 3. Letter R. E. Engel (CE) to D. H. Vassallo (NRC). "Elimination of Control Rod Drop Accident Analysis for Banked Position Withdrawal Sequence Plants," February 24, 1982 (ADAMS Accession No. ML20049H752).
- 4. Letter and enclosure from T. A. Pickens (BWROG) to NRC, "Amendment 17 to General Electric Licensing Topical Report NEDE-24011-PA," dated August 15, 1986 (ADAMS Accession No. ML20203L984).
- 5. NRC Safety Evaluation, "Relating to Amendment 17 General Electric Topical Report NEDE-24011-P, 'General Electric Standard Application for Reactor Fuel'," dated December 27, 1987 (ADAMS Accession No. ML260069M901).
- 6. American National Standard, "Nuclear Safety Criteria for the Design of Stationary Boiling Water Reactor Plants," ANSI/ANS-52.1-1983.
- 7. NUREG-0800, "Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition," Section 15.4.9, "Spectrum of Rod Drop Accidents (BWR)," Revision 3, March 2007 (ADAMS Accession No. ML070550015).
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TSTF-606, Rev. 0 Model Application DRAFT
TSTF-606, Rev. 0 Page 1
[DATE]
10 CFR 50.90 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 PLANT NAME DOCKET NO. [50]-[xxx]
SUBJECT:
Application to Revise Technical Specifications to Adopt TSTF-606, "Revise the Actions Associated with an Inoperable Rod Worth Minimizer (RWM)"
Pursuant to 10 CFR 50.90, [LICENSEE] is submitting a request for an amendment to the Technical Specifications (TS) for [PLANT NAME, UNIT NOS.].
[LICENSEE] requests adoption of TSTF-606, "Revise the Actions Associated with an Inoperable Rod Worth Minimizer (RWM)," which is an approved change to the standard TS, into the [PLANT NAME, UNIT NOS] TS. TSTF-606 revises the TS Actions associated with an inoperable RWM.
The enclosure provides a description and assessment of the proposed changes. Attachment 1 provides the existing TS pages marked to show the proposed changes. [Attachment 2 provides revised (clean) TS pages.] Attachment [3] provides the existing TS Bases pages marked to show revised text associated with the proposed TS changes and is provided for information only.
[LICENSEE] requests that the amendment be reviewed under the Consolidated Line Item Improvement Process (CLIIP). Approval of the proposed amendment is requested within 6 months of completion of the NRCs acceptance review. Once approved, the amendment shall be implemented within [90] days.
There are no regulatory commitments in this letter.
[In accordance with 10 CFR 50.91, a copy of this application, with attachments, is being provided to the designated [STATE] Official.]
[In accordance with 10 CFR 50.30(b), a license amendment request must be executed in a signed original under oath or affirmation. This can be accomplished by attaching a notarized affidavit confirming the signature authority of the signatory, or by including the following statement in the cover letter: "I declare under penalty of perjury that the foregoing is true and correct.
Executed on (date)." The alternative statement is pursuant to 28 USC 1746. It does not require notarization.]
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TSTF-606, Rev. 0 Page 2 If you should have any questions regarding this submittal, please contact [NAME, TELEPHONE NUMBER].
Sincerely,
[Name, Title]
Enclosure:
Description and Assessment Attachments: 1.
Proposed Technical Specification Changes (Mark-Up)
- 2.
[Revised Technical Specification Pages]
[3]. Proposed Technical Specification Bases Changes (Mark-Up) - For Information Only
[The attachments are to be provided by the licensee and are not included in the model application.]
cc:
NRC Project Manager NRC Regional Office NRC Resident Inspector State Contact DRAFT
TSTF-606, Rev. 0 Page 3 ENCLOSURE DESCRIPTION AND ASSESSMENT 1.0 DESCRIPTION
[LICENSEE] requests adoption of TSTF-606, "Revise the Actions Associated with an Inoperable Rod Worth Minimizer (RWM)," which is an approved change to the standard Technical Specifications (TS), into the [PLANT NAME, UNIT NOS] TS. The traveler revises the TS Actions associated with an inoperable RWM.
2.0 ASSESSMENT 2.1 Applicability of Safety Evaluation
[LICENSEE] has reviewed the safety evaluation for TSTF-606 provided to the Technical Specifications Task Force in a letter dated [DATE]. This review included the NRC staffs evaluation, as well as the information provided in TSTF-606. [LICENSEE] has concluded that the justifications presented in TSTF-606 and the safety evaluation prepared by the NRC staff are applicable to [PLANT, UNIT NOS.] and justify this amendment for the incorporation of the changes to the [PLANT] TS.
2.2 Variations
[LICENSEE is not proposing any variations from the TS changes described in TSTF-606 or the applicable parts of the NRC staffs safety evaluation.] [LICENSEE is proposing the following variations from the TS changes described in TSTF-606 or the applicable parts of the NRC staffs safety evaluation:]
[The [PLANT] TS utilize different [numbering][and][titles] than the standard TS on which TSTF-606 was based. Specifically, [describe differences between the plant-specific TS numbering and/or titles and the TSTF-606 numbering and titles.] These differences are administrative and do not affect the applicability of TSTF-606 to the [PLANT] TS.]
[The [PLANT] TS contain requirements that differ from the standard TS on which TSTF-606 was based but are encompassed in the TSTF-606 justification. [Describe the differences, including the use of any methods other than General Electric methods to establish low power control rod sequences to mitigate a CRDA, and why TSTF-606 is still applicable.]
3.0 REGULATORY ANALYSIS
3.1 No Significant Hazards Consideration Analysis
[LICENSEE] requests adoption of TSTF-606, "Revise the Actions Associated with an Inoperable Rod Worth Minimizer (RWM)," which is an approved change to the standard Technical Specifications (TS), into the [PLANT NAME, UNIT NOS] TS. The proposed change revises the TS Actions associated with an inoperable RWM.
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TSTF-606, Rev. 0 Page 4
[LICENSEE] has evaluated if a significant hazards consideration is involved with the proposed amendment(s) by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:
- 1.
Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?
Response: No The proposed change revises the TS Actions to be taken when the RWM is inoperable during a reactor startup. The change eliminates the once per calendar year restriction on startups with the RWM inoperable or after at least twelve control rods are withdrawn.
The RWM acts as a backup to the reactor operator and plant procedures to ensure control rod movement is in accordance with the Banked Position Withdrawal Sequence (BPWS) and to protect the initial conditions of the Control Rod Drop Accident (CRDA) analysis.
However, the TS continue to require that the BPWS be followed. Studies have determined that a CRDA is highly improbable and the use of the RWM is not required to provide adequate assurance a CRDA will not occur. Therefore, relying on a second qualified individual to verify that control rod movement is in accordance with the BPWS when the RWM is inoperable will not result in a significant increase in the probability of an accident. The allowance to continue startup with an inoperable RWM after at least twelve control rods are withdrawn is unnecessary when the control rods are moved in accordance with the BPWS, and has no effect on the probability of an accident.
The RWM does not mitigate any previously analyzed accident. The RWM is not assumed to operate during a CRDA or any other previously analyzed accident.
Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
- 2.
Does the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?
Response: No The proposed change revises the TS Actions to be taken when the RWM is inoperable during a reactor startup. The change eliminates the once per calendar year restriction on startups with the RWM inoperable or after at least twelve control rods are withdrawn.
The proposed change only applies when the RWM is inoperable. The RWM continues to be required to be operable per the TS and there is no change in its design function or operation. The RWM is not credited in the accident analysis and, as a result, additional reactor startups with an inoperable RWM are not a precursor to a new or different kind of accident, and do not initiate any new or different kinds of accidents not considered in the design and licensing bases.
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TSTF-606, Rev. 0 Page 5 Maintaining control rod worth is principally a manually controlled action, with the operator following the pre-established sequence. Manual control of rod withdrawals and the established sequences for movement are not being changed with the proposed amendment. The currently approved allowance for independent verification of rod movement by a second qualified individual to ensure compliance with the BPWS is also not changed with the proposed amendment. Additionally, the requirement for operable control rods to comply with the BPWS is not affected by the proposed change.
Therefore, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
- 3.
Does the proposed amendment involve a significant reduction in a margin of safety?
Response: No The proposed change revises the TS Actions to be taken when the RWM is inoperable during a reactor startup. The change eliminates the once per calendar year restriction on startups with the RWM inoperable or after at least twelve control rods are withdrawn.
The proposed change does not change the safety function of any plant equipment and does not impact any design basis accident inputs or assumptions. The proposed change does not affect any specific values that define margin as established in each plants licensing basis.
The proposed change does not alter a design basis or safety limit (i.e., the controlling numerical value for a parameter established in the UFSAR or the license), and as a result, does not significantly reduce the margin of safety.
Therefore, the proposed change does not involve a significant reduction in a margin of safety.
Based on the above, [LICENSEE] concludes that the proposed change presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of "no significant hazards consideration" is justified.
3.2 Conclusion 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.
4.0 ENVIRONMENTAL CONSIDERATION A review has determined that the proposed amendment 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 DRAFT
TSTF-606, Rev. 0 Page 6 amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or a 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, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed amendment.
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TSTF-606, Rev. 0 Technical Specifications Changes DRAFT
Control Rod Block Instrumentation 3.3.2.1 General Electric BWR/4 STS 3.3.2.1-1 Rev. 5.0 3.3 INSTRUMENTATION 3.3.2.1 Control Rod Block Instrumentation LCO 3.3.2.1 The control rod block instrumentation for each Function in Table 3.3.2.1-1 shall be OPERABLE.
APPLICABILITY:
According to Table 3.3.2.1-1.
ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One rod block monitor (RBM) channel inoperable.
A.1 Restore RBM channel to OPERABLE status.
24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> B. Required Action and associated Completion Time of Condition A not met.
OR Two RBM channels inoperable.
B.1 Place one RBM channel in trip.
1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> C. Rod worth minimizer (RWM) inoperable during reactor startup.
C.1 Suspend control rod movement except by scram.
OR C.2.1.1 Verify 12 rods withdrawn.
OR Immediately Immediately TSTF-606, Rev. 0 DRAFT
Control Rod Block Instrumentation 3.3.2.1 General Electric BWR/4 STS 3.3.2.1-2 Rev. 5.0 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME C.2.1.2 Verify by administrative methods that startup with RWM inoperable has not been performed in the last calendar year.
AND C.12.2 Verify movement of control rods is in compliance with banked position withdrawal sequence (BPWS) by a second licensed operator or other qualified member of the technical staff.
Immediately During control rod movement D. RWM inoperable during reactor shutdown.
D.1 Verify movement of control rods is in compliance with BPWS by a second licensed operator or other qualified member of the technical staff.
During control rod movement DE. One or more Reactor Mode Switch - Shutdown Position channels inoperable.
DE.1 Suspend control rod withdrawal.
AND DE.2 Initiate action to fully insert all insertable control rods in core cells containing one or more fuel assemblies.
Immediately Immediately TSTF-606, Rev. 0 DRAFT
Control Rod Block Instrumentation B 3.3.2.1 General Electric BWR/4 STS B 3.3.2.1-9 Rev. 5.0 BASES ACTIONS
REVIEWERS NOTE-----------------------------------
Certain LCO Completion Times are based on approved topical reports. In order for the licensee to use the times, the licensee must justify the Completion Times as required by the staff Safety Evaluation Report (SER) for the topical report.
A.1 With one RBM channel inoperable, the remaining OPERABLE channel is adequate to perform the control rod block function; however, overall reliability is reduced because a single failure in the remaining OPERABLE channel can result in no control rod block capability for the RBM. For this reason, Required Action A.1 requires restoration of the inoperable channel to OPERABLE status. The Completion Time of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is based on the low probability of an event occurring coincident with a failure in the remaining OPERABLE channel.
B.1 If Required Action A.1 is not met and the associated Completion Time has expired, the inoperable channel must be placed in trip within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.
If both RBM channels are inoperable, the RBM is not capable of performing its intended function; thus, one channel must also be placed in trip. This initiates a control rod withdrawal block, thereby ensuring that the RBM function is met.
The 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> Completion Time is intended to allow the operator time to evaluate and repair any discovered inoperabilities and is acceptable because it minimizes risk while allowing time for restoration or tripping of inoperable channels.
C.1, C.2.1.1, C.2.1.2, and C.2.2 With the RWM inoperable during a reactor startup, the operator is still capable of enforcing the prescribed control rod sequence. Required Action C.1 allows for the RWM Function to be performed manually and requires a double check of compliance with the prescribed rod sequence by a second licensed operator (Reactor Operator or Senior Reactor Operator) or other qualified member of the technical staff. However, the overall reliability is reduced because a single operator error can result in violating the control rod sequence. Therefore, control rod movement must be immediately suspended except by scram.
Alternatively, startup may continue if at least 12 control rods have already been withdrawn, or a reactor startup with an inoperable RWM was not TSTF-606, Rev. 0 DRAFT
Control Rod Block Instrumentation B 3.3.2.1 General Electric BWR/4 STS B 3.3.2.1-10 Rev. 5.0 performed in the last 12 months. Required Actions C.2.1.1 and C.2.1.2 require verification of these conditions by review of plant logs and control room indications. Once Required Action C.2.1.1 or C.2.1.2 is satisfactorily completed, BASES ACTIONS (continued) control rod withdrawal may proceed in accordance with the restrictions imposed by Required Action C.2.2. Required Action C.2.2 allows for the RWM Function to be performed manually and requires a double check of compliance with the prescribed rod sequence by a second licensed operator (Reactor Operator or Senior Reactor Operator) or other qualified member of the technical staff.
The RWM may be bypassed under these conditions to allow continued operations. In addition, Required Actions of LCO 3.1.3 and LCO 3.1.6 may require bypassing the RWM, during which time the RWM must be considered inoperable with Condition C entered and its Required Actions taken.
D.1 With the RWM inoperable during a reactor shutdown, the operator is still capable of enforcing the prescribed control rod sequence. Required Action D.1 allows for the RWM Function to be performed manually and requires a double check of compliance with the prescribed rod sequence by a second licensed operator (Reactor Operator or Senior Reactor Operator) or other qualified member of the technical staff. The RWM may be bypassed under these conditions to allow the reactor shutdown to continue.
DE.1 and DE.2 With one Reactor Mode Switch - Shutdown Position control rod withdrawal block channel inoperable, the remaining OPERABLE channel is adequate to perform the control rod withdrawal block function.
However, since the Required Actions are consistent with the normal action of an OPERABLE Reactor Mode Switch - Shutdown Position Function (i.e., maintaining all control rods inserted), there is no distinction between having one or two channels inoperable.
In both cases (one or both channels inoperable), suspending all control rod withdrawal and initiating action to fully insert all insertable control rods in core cells containing one or more fuel assemblies will ensure that the core is subcritical with adequate SDM ensured by LCO 3.1.1. Control rods in core cells containing no fuel assemblies do not affect the reactivity of the core and are therefore not required to be inserted. Action must TSTF-606, Rev. 0 DRAFT