ML15036A486

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License Amendment Request - Proposed Changes to the Technical Specifications to Address Transient Secondary Containment Conditions
ML15036A486
Person / Time
Site: Limerick  Constellation icon.png
Issue date: 02/02/2015
From: Jim Barstow
Exelon Generation Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML15036A486 (27)
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Text

10 CFR 50.90 February 2, 2015 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Units 1 and 2 Renewed Facility Operating License Nos. NPF-39 and NPF-85 NRC Docket Nos. 50-352 and 50-353

SUBJECT:

License Amendment Request Proposed Changes to the Technical Specifications to Address Transient Secondary Containment Conditions Pursuant to 10 CFR 50.90, "Application for amendment of license, construction permit, or early site permit," Exelon Generation Company, LLC (Exelon), proposes changes to the Technical Specifications (TS), Appendix A of Renewed Facility Operating License Nos.

NPF-39 and NPF-85 for Limerick Generating Station (LGS), Units 1 and 2, respectively.

The proposed changes revise TS Limiting Conditions for Operation (LCOs) 3.6.5.1.1, "Reactor Enclosure Secondary Containment Integrity," and 3.6.5.1.2, "Refueling Area Secondary Containment Integrity," and Surveillance Requirements (SRs) 4.6.5.1.1.a, 4.6.5.1.1.c.2, 4.6.5.1.2.a, and 4.6.5.1.2.c. The LCO is modified to add a footnote which allows secondary containment access openings to be opened intermittently under administrative control. The SRs are revised to allow transients during which the secondary containment pressure may not meet the SR pressure requirements. In addition, SRs 4.6.5.1.1.b.2 and 4.6.5.1.2.b.2 are modified to acknowledge that secondary containment access openings may be open for entry and exit. Also, the definitions for Reactor Enclosure Secondary Containment Integrity and Refueling Floor Secondary Containment Integrity, as specified in LGS TS Definitions 1.33 and 1.36, respectively, are revised for consistency to reflect the changes proposed to the TS Section 3.6.5 LCOs and SRs described above, as applicable.

Exelon has concluded that the proposed changes present no significant hazards consideration under the standards set forth in 10 CFR 50.92.

The proposed changes have been reviewed by the LGS Plant Operations Review Committee and approved by the Nuclear Safety Review Board in accordance with the requirements of the Exelon Quality Assurance Program.

This amendment request contains no regulatory commitments.

License Amendment Request Transient Secondary Containment Conditions Docket Nos. 50-352 and 50-353 February 2, 2015 Page 2 provides the evaluation of the proposed changes. Attachment 2 provides a copy of the marked up TS pages that reflect the proposed changes. Attachment 3 provides a copy of the marked up TS Bases pages that reflect the proposed changes (information only).

Exelon requests approval of the proposed amendment by February 2, 2016. Upon NRC approval, the amendment shall be implemented within 60 days of issuance.

In accordance with 10 CFR 50.91, "Notice for public comment; State consultation,"

paragraph (b), Exelon is notifying the Commonwealth of Pennsylvania of this application for license amendment by transmitting a copy of this letter and its attachments to the designated State Official.

If you have any questions or require additional information, please contact Glenn Stewart at 610-765-5529.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 2nd day of February 2015.

Respectfully, Director, Licensing & Regulatory Affairs Exelon Generation Company, LLC Attachments: 1. Evaluation of Proposed Changes

2. Markup of Proposed Technical Specifications Pages
3. Markup of Proposed Technical Specifications Bases Pages (Information Only) cc: Regional Administrator - NRC Region I w/ attachments NRC Senior Resident Inspector - Limerick Generating Station NRC Project Manager, NRA - Limerick Generating Station Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Protection

ATTACHMENT 1 License Amendment Request Limerick Generating Station, Units 1 and 2 Docket Nos. 50-352 and 50-353 EVALUATION OF PROPOSED CHANGES

Subject:

Proposed Changes to the Technical Specifications to Address Transient Secondary Containment Conditions 1.0

SUMMARY

DESCRIPTION 2.0 DETAILED DESCRIPTION

3.0 TECHNICAL EVALUATION

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria 4.2 Precedence 4.3 No Significant Hazards Consideration 4.4 Conclusions

5.0 ENVIRONMENTAL CONSIDERATION

6.0 REFERENCES

License Amendment Request Attachment 1 Transient Secondary Containment Conditions Page 1of10 Docket Nos. 50-352 and 50-353 Evaluation of Proposed Changes 1.0

SUMMARY

DESCRIPTION Pursuant to 10 CFR 50.90, "Application for amendment of license, construction permit, or early site permit," Exelon Generation Company, LLC (Exelon), proposes changes to the Technical Specifications (TS), Appendix A of Renewed Facility Operating License Nos. NPF-39 and NPF-85 for Limerick Generating Station (LGS), Units 1 and 2, respectively.

The proposed changes revise TS Limiting Conditions for Operation (LCOs) 3.6.5.1.1, "Reactor Enclosure Secondary Containment Integrity," and 3.6.5.1.2, "Refueling Area Secondary Containment Integrity," and Surveillance Requirements (SRs) 4.6.5.1.1.a, 4.6.5.1.1.c.2, 4.6.5.1.2.a, and 4.6.5.1.2.c. The LCO is modified to add a footnote which allows secondary containment access openings to be opened intermittently under administrative control. The SRs are revised to allow transients during which the secondary containment pressure may not meet the SR pressure requirements. In addition, SRs 4.6.5.1.1.b.2 and 4.6.5.1.2.b.2 are modified to acknowledge that secondary containment access openings may be open for entry and exit. Also, the definitions for Reactor Enclosure Secondary Containment Integrity and Refueling Floor Secondary Containment Integrity, as specified in LGS TS Definitions 1.33 and 1.36, respectively, are revised for consistency to reflect the changes proposed to the TS Section 3.6.5 LCOs and SRs described above, as applicable.

2.0 DETAILED DESCRIPTION The proposed changes address issues related to the secondary containment pressure and access openings. The secondary containment is a single system that performs a safety function.

There is no redundant train or system that can perform the secondary containment function should the secondary containment be inoperable.

The Action of TS LCO 3.6.5.1.1 provides a 4-hour allowed outage time to restore reactor enclosure secondary containment integrity (i.e., to restore an inoperable reactor enclosure secondary containment to operable status). As stated in the NUREG-1433, "Standard Technical Specifications, General Electric BWR/4 Plants," Revision 4.0, Volume 2, Bases, "The 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> Completion Time provides a period of time to correct the problem that is commensurate with the importance of maintaining [secondary] containment during Operational Conditions 1, 2, and 3.

This time period also ensures that the probability of an accident (requiring [secondary]

containment OPERABILITY) occurring during periods where [secondary] containment is inoperable is minimal."

The Action of TS LCO 3.6.5.1.2 requires suspending the handling of recently irradiated fuel in the secondary containment and operations with a potential for draining the reactor vessel when refueling area secondary containment integrity is not maintained during the mode of applicability.

NUREG-1022, Revision 3, "Event Report Guidelines 10 CFR 50.72 and 50.73," discusses the reporting criteria contained in the Code of Federal Regulations (CFR), Title 10, Paragraphs 50. 72 and 50.73. The discussion of 50.72(b)(3)(v) and 50.73(a)(2)(v}, "Any event or condition that ...

could have prevented the fulfillment of the safety function ... ,"states, "There are a limited number of single-train systems that perform safety functions (e.g., the HPCI system in BWRs). For such systems, inoperability of the single train is reportable even though the plant TS may allow such a condition to exist for a limited time." Under this guidance, failure to meet the reactor enclosure

License Amendment Request Attachment 1 Transient Secondary Containment Conditions Page 2of10 Docket Nos. 50-352 and 50-353 Evaluation of Proposed Changes secondary containment LCO or SRs for any period of time, even for a brief period much less than the 4-hour allowed outage time, requires declaring the reactor enclosure secondary containment inoperable and, therefore, reporting the condition under 10 CFR 50.72 and 10 CFR 50.73, as applicable. This reporting requirement has resulted in numerous Licensee Event Reports (LERs) in the last several years even though in the vast majority of cases the reactor enclosure secondary containment was restored to operable status quickly (Le., much less than the 4-hour allowed outage time) and the reactor enclosure secondary containment continued to be capable of performing its safety function. These reports are an unwarranted use of licensee and NRC resources, given that in the majority of cases the safety function of the reactor enclosure secondary containment is maintained.

To prevent the need of reporting issues that are not a loss of safety function, the following changes are proposed:

Proposed LCOs 3.6.5.1.1 and 3.6.5.1.2 Footnote: These LCOs require secondary containment integrity to be maintained (i.e., secondary containment to be operable). The corresponding NUREG-1433, LCO 3.6.4.1 Bases state, "For the secondary containment to be considered OPERABLE, it must have adequate leak tightness to ensure that the required vacuum can be established and maintained." However, there are legitimate reasons to open secondary containment access openings, such as testing and maintenance, or the movement of large equipment. An LCO footnote is proposed which allows secondary containment access openings to be opened intermittently under administrative control. This footnote will allow intermittent opening of secondary containment access openings without declaring the secondary containment inoperable with the attendant reporting requirements, as applicable.

Proposed SRs 4.6.5.1.1.a and 4.6.5.1.2.a Footnote: SRs 4.6.5.1.1.a and 4.6.5.1.2.a require the secondary containment to be greater than a required vacuum limit at all times. However, it is possible for the secondary containment pressure to be momentarily less than the required vacuum for a number of reasons, such as during entry and exit from the secondary containment with both the inner and outer doors open simultaneously, during high winds, and during maintenance, testing, or swapping of the normal ventilation subsystems. These conditions do not affect the ability of the Standby Gas Treatment System (SGTS) to establish and maintain the required vacuum in the secondary containment as assumed in the accident analyses. However, should secondary containment pressure not meet the SR 4.6.5.1.1.a and SR 4.6.5.1.2.a vacuum requirement (however briefly), the secondary containment must be declared inoperable and the event reported under 10 CFR 50.72 and 50.73. To address this situation, a footnote is added to SRs 4.6.5.1.1.a and 4.6.5.1.2.a which states, "Not required to be met during transient conditions if the Standby Gas Treatment System remains capable of establishing the required secondary containment vacuum." This footnote allows momentary transients below the required vacuum limit without declaring the secondary containment inoperable with the attendant reporting requirements, as applicable.

Proposed SRs 4.6.5.1.1.c.2 and 4.6.5.1.2.c Footnote: SRs 4.6.5.1.1.c.2 and 4.6.5.1.2.c require verification that one standby gas treatment subsystem can maintain the secondary containment pressure 2: 0.25 inch of vacuum water gauge for one hour. It is possible for the secondary containment pressure to be momentarily less than the required vacuum during the test for a number of reasons, such as entry and exit from the secondary containment with both the inner and outer access doors open simultaneously, high winds, or during maintenance, testing, or

License Amendment Request Attachment 1 Transient Secondary Containment Conditions Page 3of10 Docket Nos. 50-352 and 50-353 Evaluation of Proposed Changes swapping of the normal ventilation subsystems. These conditions do not affect the ability of the SGTS to establish and maintain the required vacuum in the secondary containment as assumed in the accident analyses. Therefore, a footnote is proposed to be added to SRs 4.6.5.1.1.c.2 and 4.6.5.1.2.c which states, "Momentary transients less than the required vacuum do not invalidate this test." This footnote allows momentary transients below the required vacuum limit without declaring the secondary containment inoperable with the attendant reporting requirements, as applicable.

Proposed SRs 4.6.5.1.1.b.2 and 4.6.5.1.2.b.2 Revision: Another issue being addressed is unintentional, simultaneous opening of both an inner and outer secondary containment access opening door. While some plants have interlocks to prevent opening both an inner and outer door, LGS does not. Under the LGS TS, opening both an inner and outer door in an access opening at the same time would result in failure to meet SR 4.6.5.1.1.b.2 or 4.6.5.1.2.b.2, as appropriate, which requires one access door in each access opening to be closed. This situation requires declaring the secondary containment inoperable with the attendant reporting requirements, as applicable. NUREG-1434 BWR/6 ISTS SR 3.6.4.1.3 contains an exception that allows both doors in an access opening to be open simultaneously for normal entry and exit, but the LGS SRs do not have such an exception. The proposed change adds the BWR/6 exception to the LGS SRs.

Proposed Definition Revisions: The definitions for Reactor Enclosure Secondary Containment Integrity and Refueling Floor Secondary Containment Integrity, as specified in LGS TS Definitions 1.33 and 1.36, respectively, are revised by adding the changes described above, as applicable, for consistency with the changes proposed to the TS Section 3.6.5 LCOs and SRs.

Proposed Bases Revision: The LGS TS 3.6.5 Secondary Containment Bases are revised consistent with the proposed changes to LCOs 3.6.5.1.1 and 3.6.5.1.2, and SRs 4.6.5.1.1.a, 4.6.5.1.1.b.2, 4.6.5.1.1.c.2, 4.6.5.1.2.a, 4.6.5.1.2.b.2, and 4.6.5.1.2.c.

3.0 TECHNICAL EVALUATION

The LGS secondary containment consists of three distinct isolable zones. Zones I and 11 are the Unit 1 and Unit 2 reactor enclosures, respectively, and Zone Ill is the common refueling area.

Each zone has an independent normal ventilation system which is capable of providing secondary containment isolation as required.

Each reactor enclosure zone completely encloses and provides secondary containment for its corresponding primary containment and supporting equipment. The common refueling area zone completely encloses and provides secondary containment for the refueling floor and spent fuel storage facilities for Unit 1 and Unit 2.

The SGTS is an engineered safety feature system that is designed to: 1) isolate and draw down the reactor enclosure and/or the refueling area secondary containment zone(s), 2) reduce the halogen and particulate concentrations in gases potentially present prior to release to the environment, and 3) maintain a vacuum in the affected secondary containment zone(s) following a design basis accident (OBA). The SGTS operates in conjunction with the Reactor Enclosure Recirculation System (RERS) which is provided to filter the halogens and particulate concentrations in gases potentially present in the reactor enclosure secondary containment

License Amendment Request Attachment 1 Transient Secondary Containment Conditions Page 4 of 10 Docket Nos. 50-352 and 50-353 Evaluation of Proposed Changes following a loss of coolant accident (LOCA). The RERS is the initial cleanup system and the SGTS is the final cleanup system before release to the environment.

It is possible for the respective secondary containment pressure to rise relative to the environmental pressure. To prevent ground level exfiltration of radioactive material while allowing the secondary containment to be designed as a conventional structure, the secondary containment requires support systems to maintain the control volume pressure at less than atmospheric pressure. During normal operation, non-accident systems are used to maintain the secondary containment at a negative pressure. SR 4.6.5.1.1.a [4.6.5.1.2.a] requires the secondary containment to be ;::: 0.25 inch of vacuum water gauge when the secondary containment is required to be operable (for the reactor enclosure secondary containment - Operational Conditions 1, 2, and 3; for refueling floor secondary containment - when recently irradiated fuel is being handled in the secondary containment, or during operations with a potential for draining the reactor vessel, with the vessel head removed and fuel in the vessel). SR 4.6.5.1.1.c.1 requires verification that the reactor enclosure secondary containment can be drawn down to be ;::: 0.25 inch of vacuum water gauge ins; 916 seconds using one standby gas treatment (SGT) subsystem. SR 4.6.5.1.1.c.2

[4.6.5.1.2.c] requires verification that the reactor enclosure secondary containment [refueling floor secondary containment] can be maintained <::: 0.25 inch of vacuum water gauge for one hour using one SGT subsystem at a flow rates; 2500 [764] cfm. Following an accident, the SGTS ensures the secondary containment pressure is less than the external atmospheric pressure.

The secondary containment boundary includes access openings. A secondary containment personnel access opening contains at least one inner and one outer door. All secondary containment access doors are normally kept closed, except when the access opening is being used for entry and exit of personnel or equipment.

The safety function of the secondary containment is to contain, dilute, and hold up fission products that may leak from primary containment following a OBA to ensure the control room operator and offsite doses are within the regulatory and NRC-approved limits. In conjunction with operation of the SGTS and closure of certain valves whose lines penetrate the secondary containment, the secondary containment is designed to reduce the activity level of the fission products that bypass or leak from primary containment, or are released from the reactor coolant pressure boundary components located in secondary containment prior to release to the environment. For the secondary containment to be considered operable, it must have adequate leak tightness to ensure that the required vacuum can be established and maintained by a single SGT subsystem when that subsystem is in operation.

The secondary containment vacuum requirements (which demonstrate leak-tightness) and the SGTS together ensure radioactive material is contained. As long as a SGT subsystem can draw down and maintain the required vacuum in the affected secondary containment when needed (as demonstrated by SR 4.6.5.1.1.c.1 or SR 4.6.5.1.1.c.2 [4.6.5.1.2.c]), the secondary containment will perform all of its safety functions.

Transients in secondary containment pressure may occur that do not affect the ability of the secondary containment to be able to perform its safety function nor do they involve any failed equipment or any failed portion of the secondary containment. Examples are:

License Amendment Request Attachment 1 Transient Secondary Containment Conditions Page 5of10 Docket Nos. 50-352 and 50-353 Evaluation of Proposed Changes

  • The simultaneous opening of both an inner and outer door in an access opening does not satisfy the current TS SR 4.6.5.1.1.b.2 [4.6.5.1.2.b.2J and may result in a temporary decrease in secondary containment vacuum below the SR limit. However, once one door is closed, the SR is met and the vacuum can be reestablished. The simultaneous opening of the inner and outer door typically lasts less than 10 seconds for personnel access but may be longer for equipment access.
  • High winds impact outside pressure, which could result in a differential pressure less than the SR limit. However, such winds also increase the dilution of any radioactive releases and the differential pressure returns to within the SR limit when wind speed drops.
  • Maintenance or testing could result in temporary opening of access doors to facilitate movement of equipment that could result in not meeting SR 4.6.5.1.1.a [4.6.5.1.2.a] and a loss of the required vacuum. As long as the breaches are controlled administratively and can be promptly closed, the secondary containment boundary can be made intact, and the SGTS remains capable of establishing the necessary vacuum.
  • Loss of the normal, non-emergency ventilation system that maintains the secondary containment vacuum, due to equipment failure or swapping of operating equipment. This loss of vacuum does not affect the secondary containment boundary, the non-emergency ventilation system is not assumed to operate during an accident, and the SGTS remains capable of establishing the necessary vacuum in the event of an accident.

In these and similar cases, the affected secondary containment remains capable of containing fission products that may leak from primary containment following a OBA or from the refueling floor, which will ensure that the control room operator doses and offsite doses are within the regulatory and NRC-approved limits.

Additionally, for many BWR plants, including LGS, that have adopted an alternative source term in accordance with 10 CFR 50.67, "Accident source term," using the methodology described in NRC Regulatory Guide 1.183, no activity releases are assumed to occur for the first two minutes following initiation of the LOCA Additionally, during drawdown of secondary containment, no credit is taken for filtering by either the SGTS or RERS. This further supports a conclusion that a temporary loss of secondary containment vacuum does not constitute a loss of safety function.

As discussed in Section 2 above, the reporting requirements in 10 CFR 50. 72 and 50. 73, as applicable, require prompt notification and submittal of an LER whenever the secondary containment is inoperable, regardless of the length of time of the inoperability or whether secondary containment could still fulfill its safety function. To address this situation, the following changes are proposed which will allow the secondary containment to be operable during brief circumstances which currently would require declaring the secondary containment inoperable.

Proposed LCO 3.6.5.1.1 [3.6.5.1.21 Footnote LCO 3.6.5.1.1 [3.6.5.1.2] requires secondary containment integrity to be maintained (i.e.,

secondary containment to be operable). The corresponding NUREG-1433, LCO 3.6.4.1 Bases state, "For the [secondary] containment to be considered OPERABLE, it must have adequate leak tightness to ensure that the required vacuum can be established and maintained." However,

License Amendment Request Attachment 1 Transient Secondary Containment Conditions Page 6 of 10 Docket Nos. 50-352 and 50-353 Evaluation of Proposed Changes sometimes there are reasons to open secondary containment access openings, such as testing and maintenance, or the movement of large equipment through the access. An LCO footnote is proposed which allows secondary containment access openings to be opened intermittently under administrative control.

The allowance to open a barrier under administrative control appears in the NUREG-1433 TS in several locations, such as the control room boundary. The administrative controls ensure the opening will be promptly closed if required. Consistent with the existing allowances in NUREG-1433, the acceptable administrative controls are described in the proposed LGS TS Bases in a manner similar to the control room boundary administrative control allowance in NUREG-1433.

The proposed LGS TS Bases state:

This footnote only applies to access openings in the secondary containment that can be rapidly restored to the design condition. These controls should be proceduralized and consist of stationing a dedicated individual at the opening who is in continuous communication with the operators in the control room. This individual will have a method to rapidly close the opening and to restore the secondary containment boundary to a condition equivalent to the design condition when a need for secondary containment isolation is indicated.

The ability to open secondary containment access openings under administrative control, even if it means the secondary containment boundary is temporarily not intact, is acceptable due to the low probability of an event that could pressurize the secondary containment during the short time in which the secondary containment is open and the presence of administrative controls to rapidly close the opening. During these conditions, the SGTS and RERS are still capable of performing all of their intended safety functions. The risk to the public from this allowance is less than the risk associated with the current 4-hour allowed outage time to restore an inoperable reactor enclosure secondary containment, because the LCO footnote requires administrative controls to be able to rapidly restore the secondary containment to operable status.

Proposed SR 4.6.5.1.1.a [4.6.5.1.2.aJ Footnote As discussed above, the secondary containment vacuum is required to be greater than the required limit at all times. To address situations in which SR 4.6.5.1.1.a [4.6.5.1.2.a] may not be met due to transient conditions, a footnote is proposed. The footnote states:

Not required to be met during transient conditions if the Standby Gas Treatment System remains capable of establishing the required secondary containment vacuum.

Transient conditions in which secondary containment pressure may be less than the required vacuum may occur in many situations, such as, but not limited to, entry and exit from the secondary containment, high winds, maintenance or testing of the secondary containment, and failure or change of operating normal ventilation subsystems. As discussed above, secondary containment operability is based on its ability to contain, dilute, and hold up fission products that may leak from primary containment following a OBA. Transient conditions which do not affect the ability of the secondary containment to perform this function should not result in failure to meet the SR. As stated in 10 CFR 50.36(c)(3), the purpose of an SR is to verify the LCO is met, and LCO 3.6.5.1.1 [3.6.5.1.2] requires secondary containment integrity to be maintained (i.e.,

secondary containment operable). If a transient condition does not affect the ability of the SGTS

License Amendment Request Attachment 1 Transient Secondary Containment Conditions Page 7 of 10 Docket Nos. 50-352 and 50-353 Evaluation of Proposed Changes to establish the required vacuum, the secondary containment is operable and the SR should be considered met.

Proposed SR 4.6.5.1.1.c.2 [4.6.5.1.2.c] Footnote SR 4.6.5.1.1.c.2 [4.6.5.1.2.c] requires secondary containment pressure to be maintained greater than the vacuum limit for one hour using one SGT subsystem. A footnote to the SR is proposed which states:

Momentary transients less than the required vacuum do not invalidate this test.

The footnote is similar to the NUREG-1433 Notes in SR 3.8.1.3, SR 3.8.1.14, and SR 3.8.1.15, which state, "Momentary transients outside the load range do not invalidate this test." Similar to the performance of these diesel generator tests, momentary transients outside of the required secondary containment pressure may occur during the test due to, for example, entry and exit from the secondary containment or high winds, that are not indicative of an inability of the SGTS to establish the post-accident secondary containment vacuum. The proposed footnote addresses these situations while ensuring the secondary containment pressure can be established and maintained.

Proposed SR 4.6.5.1.1.b.2 [4.6.5.1.2.b.2] Revision SR 4.6.5.1.1.b.2 [4.6.5.1.2.b.2] is proposed to be revised to include the same exception as the NUREG-1434 BWR/6 SR 3.6.4.1.3. The text in italics, below, is added.

Verify in accordance with the Surveillance Frequency Control Program that: . . . At least one door in each access to the reactor enclosure [refueling area] secondary containment is closed, except when the access opening is being used for entry and exit.

LGS does not have interlocks to prevent opening both an inner and outer door of a particular access opening simultaneously during entry and exit. Only an alarm function is provided.

NUREG-1434 BWR/6 ISTS SR 3.6.4.1.3 contains an exception that allows both doors in an access opening to be opened simultaneously for normal entry and exit, but the LGS TS SR 4.6.5.1.1.b.2 [4.6.5.1.2.b.2] does not have such an exception. This allowance is reasonable because the doors will be closed following entry or exit, restoring the secondary containment boundary.

Proposed Bases Revisions The LGS TS 3.6.5 Secondary Containment Bases are revised consistent with the proposed changes to LCOs 3.6.5.1.1 and 3.6.5.1.2, and SRs 4.6.5.1.1.a, 4.6.5.1.1.b.2, 4.6.5.1.1.c.2, 4.6.5.1.2.a, 4.6.5.1.2.b.2, and 4.6.5.1.2.c.

4.0 REGULATORY EVALUATION

4.1 Applicable Regulatory Requirements/Criteria The following regulatory requirements have been considered:

License Amendment Request Attachment 1 Transient Secondary Containment Conditions Page 8of10 Docket Nos. 50-352 and 50-353 Evaluation of Proposed Changes

  • Title 10 of the Code of Federal Regulations (10 CFR), Section 50.36, "Technical specifications," in which the Commission established its regulatory requirements related to the contents of the TS. Specifically, 10 CFR 50.36(c)(2) states, in part, "Limiting conditions for operation are the lowest functional capability or performance levels of equipment required for safe operation of the facility." 10 CFR 50.36(c)(3) states, "Surveillance requirements are requirements relating to test, calibration, or inspection to assure that the necessary quality of systems and components is maintained, that facility operation will be within safety limits, and that the limiting conditions for operation will be met."

The proposed changes to the secondary containment LCO and SRs do not affect compliance with these regulations.

The applicable 1O CFR Part 50, Appendix A, General Design Criteria, was considered as follows:

  • Criterion 16 -Containment Design. Reactor containment and associated systems shall be provided to establish an essentially leak-tight barrier against the uncontrolled release of radioactivity to the environment and to assure that the containment design conditions important to safety are not exceeded for as long as postulated accident conditions require.

The proposed changes do not alter the design of the secondary containment or its ability to establish an essentially leak-tight barrier against the uncontrolled release of radioactivity.

4.2 Precedence None.

4.3 No Significant Hazards Consideration Exelon Generation Company, LLC (Exelon), proposes changes to the Technical Specifications (TS), Appendix A of Renewed Facility Operating License Nos. NPF-39 and NPF-85 for Limerick Generating Station (LGS), Units 1 and 2, respectively.

The proposed changes revise TS Limiting Conditions for Operation (LCOs) 3.6.5.1.1, "Reactor Enclosure Secondary Containment Integrity," and 3.6.5.1.2, "Refueling Area Secondary Containment Integrity," and Surveillance Requirements (SRs) 4.6.5.1.1.a, 4.6.5.1.1.c.2, 4.6.5.1.2.a, and 4.6.5.1.2.c. The LCO is modified to add a footnote which allows secondary containment access openings to be opened intermittently under administrative control. The SRs are revised to allow transients during which the secondary containment pressure may not meet the SR pressure requirements. In addition, SRs 4.6.5.1.1.b.2 and 4.6.5.1.2.b.2 are modified to acknowledge that secondary containment access openings may be open for entry and exit. Also, the definitions for Reactor Enclosure Secondary Containment Integrity and Refueling Floor Secondary Containment Integrity, as specified in LGS TS Definitions 1.33 and 1.36, respectively, are

License Amendment Request Attachment 1 Transient Secondary Containment Conditions Page 9 of 10 Docket Nos. 50-352 and 50-353 Evaluation of Proposed Changes revised for consistency to reflect the changes proposed to the TS Section 3.6.5 LCOs and SRs described above, as applicable.

Exelon has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:

1. Do the proposed changes involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No. The proposed changes allow temporary conditions during which the secondary containment LCO and SRs are not met. The secondary containment is not an initiator of any accident previously evaluated. As a result, the probability of any accident previously evaluated is not increased. The consequences of an accident previously evaluated while utilizing the proposed changes are no different than the consequences of an accident while utilizing the existing 4-hour allowed outage time for an inoperable reactor enclosure secondary containment. As a result, the consequences of an accident previously evaluated are not significantly increased.

Therefore, the proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. Do the proposed changes create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No. The proposed changes do not alter the protection system design, create new failure modes, or change any modes of operation. The proposed changes do not involve a physical alteration of the plant, and no new or different kind of equipment will be installed. Consequently, there are no new initiators that could result in a new or different kind of accident.

Therefore, the proposed changes do not create the possibility of a new or different kind of accident from any accident previously evaluated.

3. Do the proposed changes involve a significant reduction in a margin of safety?

Response: No. The proposed changes allow temporary conditions during which the secondary containment LCO and SRs are not met. Temporary conditions in which the secondary containment vacuum is below the required limit are acceptable provided the conditions do not affect the ability of the Standby Gas Treatment System to establish the required secondary containment vacuum. This condition is incorporated in the proposed changes by requiring the condition to be momentary or under administrative control such that the conditions equivalent to the design condition can be quickly restored should secondary containment vacuum be required. Therefore, the safety function of the secondary containment is not affected. The allowance for both an inner and outer secondary containment

License Amendment Request Attachment 1 Transient Secondary Containment Conditions Page 10of10 Docket Nos. 50-352 and 50-353 Evaluation of Proposed Changes access door to be open simultaneously for entry and exit does not affect the safety function of the secondary containment as the doors are promptly closed after entry or exit, thereby restoring the secondary containment boundary.

Therefore, the proposed changes do not involve a significant reduction in a margin of safety.

Based on the above, Exelon concludes that the proposed amendment 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.

4.4 Conclusions In conclusion, based on the considerations discussed above, (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.

5.0 ENVIRONMENTAL CONSIDERATION

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 amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent 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.

6.0 REFERENCES

1. NUREG-1433, "Standard Technical Specifications, General Electric BWR/4 Plants,"

Revision 4.0, dated April 2012.

2. NUREG-1434, "Standard Technical Specifications, General Electric BWR/6 Plants,"

Revision 4.0, dated April 2012.

ATTACHMENT 2 License Amendment Request Limerick Generating Station, Units 1 and 2 Docket Nos. 50-352 and 50-353 Proposed Changes to the Technical Specifications to Address Transient Secondary Containment Conditions Markup of Proposed Technical Specifications Pages Unit 1 TS Pages 1-6 1-7 3/4 6-46 3/4 6-47 Unit 2 TS Pages 1-6 1-7 3/4 6-46 3/4 6-47

1. PURGE or PURGING hall be the controlled process of discharging air or ga from a confinement to maintain rature, pres ure, humidi concentration or other operating condition, in uch a manner that cement air or ga i required to puri the confinement.

shall be total reactor core heat transfer rate to of 1 MWt.

/~

1. 33 REACTOR ENCLOSURE SECONDARY CONTAINMENT INTEGRITY shall exis~hen~

All reactor enclo ure econdary containment penetrations required to be closed during accident conditions are either:

ble of being closed by an OPERABLE secondary containment a tic isolation system, or Closed by at least one manual valve, blind flange, slide gate damper, or deactivated automatic valve secured in its closed position, except as provided by Specification 3.6.5.2.1.

b. All reactor enclosure secondary containment hatches and blowout panels are closed and sealed.
c. The standby gas treatment system is in compliance with the requirements of fication .6.5.3.
d. The reactor enclosure recirculation system is in compliance with the requirements of Specification 3.6.5.4.
e. At least one door in each access to the reactor enclosure secondary containment is closed~
f. The sealing mechanism associated with each reactor enclosure secondary containment penetration, e.g., welds, bellows, or 0-rings, is OPERABLE.
g. The pressure within the reactor enclosure secondary containment is less than equal to the value required by Specification 4 . 6 . 5 . 1. l .....*__*.,,. . . ._

1.34 REACTOR PROTECTION SYSTEM RESPONSE TIME shall be the time interval from when the monitored parameter exceeds its trip setpoint at the channel sensor until de energization of the scram pilot valve solenoids. The response time may be measured by any series of sequential, overlapping or total steps such that the entire response time is measured.

1.35 RECENTLY IRRADIATED FUEL is fuel that has occupied part of a critical reactor core within the previous 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

Insert 1.36 REFUELING FLOOR SECONDARY CONTAINMENT INTEGRITY shall exis *when:

a. All refueling floor secondary containment penetrations required to be closed during accident conditions are either:

~

LIMERICK UNIT 1 1-6 Amendment No. +.:;,~.~.~.-1-&e, 201

(Continued)

1. of being closed an OPERAS econdary containment ic isolation system, or
2. Closed at lea one manual valve, blind flange, ga

, or deactivated automatic valve ecured in i ed pos tion, as provided fi tion

b. All refueling floor econdary containment hatche and blowout re closed and sealed.
c. The gas treatment system in iance with the requirements of fication 3.6.5.3.
d. At least one door in each access to the refueling floor secondary containment is closed~

The sealing mechanism associated with each refueling floor seconda containment penetration, e.g., welds, bellows. or 0 rings, i OP LE.

f. The pressure within the refueling floor secondary containment i less than or equal to the value required by Specification 4.6.5.1.2 **

Insert 1.37 A REPORTABLE EVENT shall be any of those conditions specified in Section 50.73 to 10 CFR Part 50.

l.37a RESTRICTED AREA means an area, access to which is limited the licensee for the purpose of protecting individuals against undue ri ks from exposure to radiation and radioactive materials. RESTRICTED AREA does not include areas used as residential quarters, but separate rooms in a residential building may be set apart as a RESTRICTED AREA.

1. 38 (Deleted)

SHUTDOWN MARGIN 1.39 SHUTDOWN MARGIN shall be the amount of reactivity by which the reactor is subcritical or would be subcritical assuming all control rods are fully inserted except for the single control rod of highest reactivity worth which is assumed to be fully withdrawn and the reactor is in the shutdown condition; cold, i.e. 68°F; and xenon free.

SITE BOUNDARY 1.40 The SITE BOUNDARY shall be that line as defined in Figure 5.1.3 la.

SOURCE CHECK 1.41 A SOURCE CHECK shall be the qualitative assessment of channel response when the channel sensor is exposed to a radioactive source.

~

LIMERICK UNIT 1 1-7 Amendment No. ~ *.e.e..~,-1-&S.-+/-&7, 207

3.6.5.l.l REACTOR ENCLOSURE ECONDARY CONTAINMENT NTEGRITY hall be maintaine~ .----------.

~

OPERATIONAL CONDITIONS 1, 2, and Without REACTOR ENCLOSURE SECONDARY CONTAINMENT INTEGRITY, tore REACTOR ENCLOSURE SECONDARY CONTAINMENT INTEGRITY within 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or be in at least HOT SHUTDOWN within the next 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

4.6.5.l.1 REACTOR ENCLOSURE SECONDARY CONTAINMENT INTEGRITY shall be demon-strated by:

a. Veri ing in accordance with the Surveillance Frequency Control Program that the pressure within the reactor enclosure econdary ntainment is greater than or equal to 0.25 inch of vacuum water gaug~,*~.*__,,.,... ___ Insert
b. Verifying in accordance with the Surveillance Frequency Control Program that:
1. All reactor enclosure secondary containment equipment hatches and blowout panels are closed and sealed.
2. At least one door in each access to the reactor enclosure secondary containment is closed.~
3. All reactor enclosure secondary containment penetrations not capable of being closed by OPERABLE secondary containment auto-matic isolation dampers/valves and required to be closed during accident conditions are closed by valves, blind flanges, slide gate dampers or deactivated automatic dampers/valves secured in position.
c. In accordance with the Surveillance Frequency Control Program:
1. Verifying that one standby gas treatment subsystem will draw down the reactor enclosure secondary containment to greater than or equal to 0.25 inch of vacuum water gauge in less than or equal to 916 seconds with the reactor enclosure recirc system in operation and
2. Operating one standby gas treatment subsystem for one hour and maintaining greater than or equal to 0.25 inch of vacuum water gauge in the reactor enclosure secondary containment at a flow rate not exceeding 2500 cfm with wind speeds of~ 7.0 mph as measured on the wind instrument on Tower 1, elevation 30' ~

if that instrument is unavailable, Tower 2, elevation 159'***

~ Insert LIMERICK - UNIT 1 3/4 6-46 Amendment No. &, ++/-, Q..&, ~. ~

3. 6 . . 1. REFUELING AREA SECONDARY CONTAINMENT INTEGRITY shall be maintaine~ ...-----.

-,~

When RECENTLY IRRADIATED FU L i being handled in the secondary containment, or during operations with a al for draining the reactor vessel, with the vessel head removed and fuel in the ve sel.

Without REFUELING AREA ECONDARY CONTAINMENT INTEGR TY, sus handling of RECENTLY IRRADIATED FUEL in the secondary containment and operations with a potential for draining the reactor ves l. The provi ion of fication 3.0.3 are not applicable.

4.6.5.1.2 REFUELING AREA SECONDARY CONTAINMENT INTEGRITY shall be demonstrated

a. Veri ing in accordance with the Surveillance uency Control Program that the pressure within the refueling area secondary co ainment is greater than or equal to 0.25 inch of vacuum water gaug ** ~1-n_s_e_rt~
b. Veri ing in accordance with the Surveillance Frequency Control Program that:
1. All refueling area secondary containment equipment hatches and blowout panels are closed and sealed.
2. At least one door in each access to the refueling area secondary containment is closed.~
3. All refueling area secondary containment penetrations not capable of being closed by OPERABLE secondary containment automatic iso lation dampers/valves and required to be closed during accident conditions are closed by valves, blind flanges, slide gate dampers or deactivated automatic dampers/valves secured in position.
c. In accordance with the Surveillance Frequency Control Program:

Operating one standby gas treatment subsystem for one hour and main-taining greater than or equal to 0.25 inch of vacuum water gauge in the r ueling area secondary containment at a flow rate not exceeding 764 cf *** Insert

~

LIMERICK UNIT 1 3/4 6-47 Amendment No. 9, ++/-, -+/--&§., -+/--&&

be the controlled proces of di charging ir r ga from a confinement to maintain rature, pres ure, humidi concentration or other operating condition, in uch a manner that acement air or gas is red to puri the confinement.

shall be a total reactor core t tran r rate to the reactor coolant of 3515 MWt.

Insert 1.33 REACTOR ENCLOSURE SECONDARY CONTAINMENT INTEGRITY hall exi

a. All reactor enclosure secondary containment tion required to be closed during accident conditions are either:
1. Capable of being closed by an OPERABLE secondary containment automatic isolation , or
2. Closed by at least one manual valve, blind flange, slide gate damper or deactivated automatic valve ecured in its closed position, except as provided by fication 3.6.5.2.1.
b. All reactor enclosure secondary containment hatches and blowout s are closed and sealed.
c. The standby gas treatment system is in compliance with the requirements of Specification 3.6.5.3.
d. The reactor enclosure recirculation is in compliance with the requirements of Specification 3.6.5.4.
e. At least one door in each access to the reactor enclosure secondary containment is closed~
f. The sealing mechanism associated with each reactor enclosure secondary containment penetration, e.g., welds, bellows, or 0-rings, is OPERABLE.
g. The pressure within the reactor enclosure secondary containment is ~

less than or equal to the value required by Specification 4.6.5.1.l **.

REACTOR PROTECTION SYSTEM RESPONSE TIME Insert 1.34 REACTOR PROTECTION SYSTEM RESPONSE TIME shall be the time interval from when the monitored parameter exceeds its trip setpoint at the channel sensor until de energization of the scram pilot valve solenoids. The response time may be measured by any series of sequential, overlapping or total steps such that the entire response time is measured.

RECENTLY IRRADIATED FUEL 1.35 RECENTLY IRRADIATED FUEL is fuel that has occupied part of a critical reactor core within the previous 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

Insert 1.36 REFUELING FLOOR SECONDARY CONTAINMENT INTEGRITY shall exis

a. All refueling floor secondary containment penetrations required to be closed during accident conditions are either:

~

LIMERICK - UNIT 2 1 6 Amendment No. 4&.~.~.-+/-46-. 163

(Continued)

1. ed an OPERABLE second ry containment a ion system, or manual valve, blind flange, lide gate vated utomati valve ecured in i closed provided ification .6.5 . . 2.
b. All refueling floor second ry containment ha and blowout s are closed and led.
c. in iance with the requirements
d. At one door in ch a to the refueling floor secondary containment cl ed~
e. The ling mechanism a ociated with each refueling floor secondary containment ration, e.g., welds, bellows, or 0-rings, is OPERABLE.
f. The pres ure within the refueling floor secondary containment i less than or equal to the value required by fication 4.6.5.1.2 **

Insert 1.37 A REPORTABLE EVENT hall be any of those conditions specified in Section 50.73 to 10 CFR Part 50.

l.37a RESTRICTED AREA means an area, access to which is limited by the licensee for the purpose of ng individual against undue risks from exposure to radiation and radioactive materials. RESTRICTED AREA does not include areas used as residential quarters, but separate rooms in a residential building may be set apart as a RESTRICTED AREA.

1. 38 (Deleted)

SHUTDOWN MARGIN 1.39 SHUTDOWN MARGIN shall be the amount of reactivity by which the reactor is subcritical or would be subcritical assuming all control rods are fully inserted except for the single control rod of highest reactivity worth which is assumed to be fully withdrawn and the reactor is in the shutdown condition; cold, i.e. 68°F; and xenon free.

SITE BOUNDARY 1.40 The SITE BOUNDARY shall be that line as defined in Figure 5.1.3 la.

1.41 A SOURCE CHECK shall be the qualitative assessment of channel response when the channel sensor is exposed to a radioactive source.

~

LIMERICK UNIT 2 1-7

. 6. .1. REACTOR ENCLOSURE SECONDARY CONTAINMENT INTEGRITY shall be maintaine~ .---------.

-,~

OPERATIONAL CONDITIONS 1, 2, and 3.

Without REACTOR ENCLOSURE SECONDARY CONTAINMENT INTEGRITY, restore REACTOR ENCLOSURE SECONDARY CONTAINMENT INTEGRITY within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or be in at least HOT SHUTDOWN within the next 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

4.6.5.1.1 REACTOR ENCLOSURE SECONDARY CONTAINMENT INTEGRITY shall be demon strated by:

a. Verifying in accordance with the Surveillance Frequency Control Program that the pressure within the reactor enclosure secondary conta* ent is greater than or equal to 0.25 inch of vacuum water gaug **.

Insert

b. Veri ing in accordance with the Surveillance Frequency Control Program that:
1. All reactor enclosure secondary containment equipment hatches and blowout panels are closed and sealed.
2. At least one door in each access to the reactor enclosure secondary containment is closed.

1msert 1

3. All reactor enclosure secondary containment penetrations not capable of being closed by OPERABLE secondary containment auto-matic isolation dampers/valves and required to be closed during accident conditions are closed by valves, blind flanges, slide gate dampers or deactivated automatic dampers/valves secured in position.
c. In accordance with the Surveillance Frequency Control Program:
1. Verifying that one standby gas treatment subsystem will draw down the reactor enclosure secondary containment to greater than or equal to 0.25 inch of vacuum water gauge in less than or equal to 916 seconds with the reactor enclosure recirc system in operation, and
2. Operating one standby gas treatment subsystem for one hour and maintaining greater than or equal to 0.25 inch of vacuum water gauge in the reactor enclosure secondary containment at a flow rate not exceeding 2500 cfm with wind speeds of~ 7.0 mph as measured on the wind instrument on Tower 1, elevation 30' ~--- ..----:-i

~ if that instrument is unavailable, Tower 2, elevation 159'~

LIMERICK - UNIT 2 3/4 6-46 Amendment No. J4, &&, -14+

3.6.5.1.2 REFUELING AREA SECONDARY CONTAINMENT INTEGRITY shall maintaine~

When RECENTLY IRRADIATED FUEL i being handled in the secondary containment, or during operation with a al for draining the reactor vessel, with the vessel head removed and fuel in the vessel.

Without REFUELING AREA SECONDARY CONTAINMENT INTEGR TY, handling of RECENTLY IRRADIATED FUEL in the secondary containment, and operations with a al for draining the reactor vessel. The provi ion of ifica tion 3.0.3 are not applicable.

4.6.5.1.2 REFUELING AREA SECONDARY CONTAINMENT INTEGRITY shall be demonstrated by:

a. Verifying in accordance with the Surveillance Frequency Control Program that the pressure within the refueling area secondary cont~* ent is greater than or equal to 0.25 inch of vacuum water gaug **
  • Insert
b. Verifying in accordance with the Surveillance Frequency Control Program that:
1. All refueling area secondary containment equipment hatches and blowout panels are closed and sealed.
2. At least one door in each access to the refueling area secondary containment is closed.
3. All refueling area secondary containment penetrations not capable of being closed by OPERABLE secondary containment automatic iso-lation dampers/valves and required to be closed during accident conditions are closed by valves, blind flanges, slide gate dampers or deactivated automatic dampers/valves secured in position.
c. In accordance with the Surveillance Frequency Control Program:

Operating one standby gas treatment subsystem for one hour and main-taining greater than or equal to 0.25 inch of vacuum water gauge in the eling area secondary containment at a flow rate not exceeding 764 cf ***

Insert LIMERICK - UNIT 2 3/4 6-47 Amendment No. J4, ..JA.e., -+/-4+

TS 3/4.6.5.1 INSERTS Insert 1

, except when the access opening is being used for entry and exit.

Insert 2

Insert 3

Insert 4

      • Momentary transients less than the required vacuum do not invalidate this test.

ATTACHMENT 3 License Amendment Request Limerick Generating Station, Units 1 and 2 Docket Nos. 50-352 and 50-353 Proposed Changes to the Technical Specifications to Address Transient Secondary Containment Conditions Markup of Proposed Technical Specifications Bases Pages (Information Only)

Unit 1 TS Bases Page B 3/4 6-5 Unit 2 TS Bases Page B 3/4 6-5

Secondary containment i desi to mrn1m1 any ground level relea of radioactive material which may ult from an acciden . The Reactor Enclosure and associated structures provide second ry containment dur ng normal ration when the d 1 is sea 1ed and in servi At other the d l may be open and, when required, secondary containment i pecified.

Establishing and maintaining a vacuum in the ctor enclo ure secondary containment with the gas treatment in accordance with the Surveillance Control Program, along with the surveillance of the door ,

hatches, dampers and valves, is to ensure that there are no violations of the i ri of the econdary containment.

The OPERABILITY of the reactor enclosure recircul on and the gas treatment systems en ures that sufficient iodine removal capabili will be available in the event of a LOCA. The reduction in containment iodine inventory reduces the resulting SITE BOUNDARY and Control Room radiation doses associated with containment leakage. The on of these systems and resultant iodine removal capacity are consistent with the assumptions used in the LOCA analysis. Provisions have been made to continuously purge the filter plenums with instrument air when the filters are not in use to prevent buildup of moisture on the adsorbers and the HEPA filters.

As a result of the Alternative Source Term (AST) project, secondary containment integrity of the refueling area is not required during certain conditions when handling irradiated fuel or during CORE ALTERATIONS and alignment of the Standby Gas Treatment System to the refueling area is not required. The control room dose analysis for the Fuel Handling Accident (FHA) is based on unfiltered releases from the South Stack and therefore, does not require the Standby Gas Treatment System to be aligned to the refueling area.

However, when handling RECENTLY IRRADIATED FUEL or during operations with a potential for draining the reactor vessel with the vessel head removed and fuel in the vessel, secondary containment integrity of the refueling area is required and alignment of the Standby Gas Treatment System to the refueling area is required.

The AST fuel handling analysis does not include an accident involving RECENTLY IRRADIATED FUEL or an accident involving draining the reactor vessel.

The Standby Gas Treatment System is required to be OPERABLE when handling irradiated fuel, handling RECENTLY IRRADIATED FUEL, during CORE ALTERATIONS and during operations with a potential to drain the vessel with the vessel head removed and fuel in the vessel. Fuel Handling Accident rel eases from the North Stack must be filtered through the Standby Gas Treatment System to maintain control room doses within regulatory limits. The OPERABILITY of the Standby Gas Treatment System assures that releases, if made through the North Stack, are filtered prior to release.

LIMERICK - UNIT 1 B 3/4 6 5 Amendment No. 6,4-0 ,+/-G-6,~.

-+/--&&,~. ECR LG 09 00052

to m1n1m1ze any ground level release of result from an accident. The Reactor Enclosure provide econdary containment during normal operation when and in serv At other imes the d l may be open secondary containment i ri is specified.

Establi hing and maintaining a vacuum in the reactor enclosure secondary containment with the ga treatment in accordance with the Surveillance Control Program, along with the surveillance of the doors, hatches, dampers and valves, i to ensure that there are no violations of the integrity of the secondary containment.

The OPERABILITY of the reactor enclosure recirculation and the standby gas treatment ensures that sufficient iodine removal capability will be availabl in the event of a LOCA. The reduction in containment iodine inventory reduces the resulting SITE BOUNDARY and Control Room radiation doses associated with containment leakage. The operation of these and resultant iodine removal capacity are consistent with the assumptions used in the LOCA analysis. Provisions have been made to continuously purge the filter plenums with instrument air when the filters are not in use to prevent buildup of moisture on the adsorbers and the HEPA filters.

As a result of the Alternative Source Term (AST) project, secondary containment i ity of the refueling area is not required during certain conditions when handling irradiated fuel or during CORE ALTERATIONS and alignment of the Gas Treatment tern to the refueling area is not required. The control room dos analysis for the Fuel Handling Accident (FHA) is based on unfiltered releases from the South Stack and therefore, does not require the Standby Gas Treatment System to be aligned to the refueling area.

However, when handling RECENTLY IRRADIATED FUEL or during operations with a potential for draining the reactor vessel with the vessel head removed and fuel in the vessel, secondary containment integrity of the refueling area is required and alignment of the Standby Gas Treatment System to the refueling area is required.

The AST fuel handling analysis does not include an accident involving RECENTLY IRRADIATED FUEL or an accident involving draining the reactor vessel.

The Standby Gas Treatment System is required to be OPERABLE when handling irradiated fuel, handling RECENTLY IRRADIATED FUEL, during CORE ALTERATIONS and during operations with a potential to drain the vessel with the vessel head removed and fuel in the vessel. Fuel Handling Accident rel eases from the North Stack must be filtered through the Standby Gas Treatment System to maintain control room doses within regulatory limits. The OPERABILITY of the Standby Gas Treatment System assures that releases, if made through the North Stack, are filtered prior to release.

LIMERICK - UNIT 2 B 3/4 6-5 Amendment No. J4.,.&J:.,.@6,-+/-46-,-+/-47-,

ECR LG 09-00052

TS 3/4.6.5 BASES INSERT The LCO is modified by a footnote which allows secondary containment access openings to be opened intermittently under administrative control. This footnote is not required for secondary containment access door entry and exit that is permitted by surveillances 4.6.5.1.1.b.2 and 4.6.5.1.2.b.2. This footnote only applies to access openings in the secondary containment that can be rapidly restored to the design condition under administrative controls. These controls should be proceduralized and consist of stationing a dedicated individual at the opening who is in continuous communication with the operators in the control room. This individual will have a method to rapidly close the opening and to restore the secondary containment boundary to a condition equivalent to the design condition when a need for secondary containment isolation is indicated. The ability to open secondary containment access openings under administrative control, even if it means the secondary containment boundary is temporarily not intact, is acceptable due to the low probability of an event that could pressurize the secondary containment during the short time in which the secondary containment is open and the presence of administrative controls to rapidly close the opening.

Surveillances 4.6.5.1.1.a and 4.6.5.1.2.a are each modified by a footnote which states the surveillance is not required to be met during transient conditions if the Standby Gas Treatment System remains capable of establishing the required secondary containment vacuum. Transient conditions in which secondary containment pressure may be less than the required containment vacuum may occur in many situations, such as, but not limited to, entry and exit from the secondary containment, high winds, maintenance or testing of the secondary containment, and failure or change of operating normal ventilation subsystems. These transient conditions are permitted if they do not impair the ability of the Standby Gas Treatment System to establish the post-accident secondary containment vacuum assumed in the accident analyses.

Surveillances 4.6.5.1.1.b.2 and 4.6.5.1.2.b.2 require verifying that one secondary containment access door in each access opening is closed which provides adequate assurance that exfiltration from the secondary containment will not occur. An access opening contains at least one inner and one outer door. The intent is to not breach the secondary containment, which is achieved by maintaining the inner or outer portion of the barrier closed, except when the access opening is being used for entry and exit.

Surveillances 4.6.5.1.1.c.2 and 4.6.5.1.2.c are each modified by a footnote which states that momentary transients less than the required vacuum do not invalidate the test.

Momentary conditions during the test in which secondary containment pressure is less than the required containment vacuum may occur due to, for example, entry and exit from the secondary containment and high winds. These momentary transients are not indicative of an inability of the Standby Gas Treatment System to establish the post-accident secondary containment vacuum.

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