NOC-AE-03001487, Proposed Revised Change to Containment Purge Radiation Monitoring and Withdrawal of Proposed Change to Reactor Coolant System Leakage Detection Technical Specification

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Proposed Revised Change to Containment Purge Radiation Monitoring and Withdrawal of Proposed Change to Reactor Coolant System Leakage Detection Technical Specification
ML031530094
Person / Time
Site: South Texas  STP Nuclear Operating Company icon.png
Issue date: 05/22/2003
From: Jordan T
South Texas
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
NOC-AE-03001487, STI: 31574217
Download: ML031530094 (19)
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Nuclear Operating Company South Tes Prqecd Electric Generting Station PO. Bx 289 Wadsorth Ts 77483 May 22, 2003 NOC-AE-03001487 10CFR50.90 STI: 31574217 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852 South Texas Project Units I and 2 Docket Nos. STN 50-498, STN 50-499 Proposed Revised Change to Containment Purge Radiation Monitoring and Withdrawal of Proposed Change to Reactor Coolant System Leakage Detection Technical Specifications

References:

1) Letter dated February 14, 2002, from J. J. Sheppard, STPNOC, to NRC Document Control Desk, "Proposed Change to Containment Purge Radiation Monitoring and Reactor Coolant System Leakage Detection Technical Specifications" (NOC-AE-02001247)
2) Letter dated January 7, 2003, from T. J. Jordan, STPNOC, to NRC Document Control Desk, "Additional Information Regarding Proposed Changes to Containment Ventilation Isolation Technical Specifications" (NOC-AE-02001435)

STP Nuclear Operating Company (STPNOC) submits the attached revised proposed amendment to South Texas Project Operating Licenses, NPF-76 and NPF-80. This license amendment request proposes revising Technical Specification 3.3.2 governing radiation monitoring instrumentation to relax restrictions on containment purge valve operation.

The changes proposed in Reference I to allow purge operation with two inoperable containment purge radiation monitor channels provided there is alternate monitoring capability and the changes proposed for Technical Specification 3/4.4.6.1 are withdrawn.

STPNOC requests approval of the proposed amendment by September 30, 2003. STPNOC requests 60 days for implementation of the amendment after it is approved.

The STPNOC Plant Operations Review Committee and Nuclear Safety Review Board have reviewed and concurred with the proposed change to the Technical Specifications.

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NOC-AE-03001487 Page 2 In accordance with 10 CFR 50.91(b), STPNOC is notifying the State of Texas of this request for license amendment by providing a copy of this letter and its attachments.

If there are any questions regarding the proposed amendment, please contact Mr. A. W. Harrison (361) 972-7298 or me at (361) 972-7902.

I declare under penalty of perjury that the foregoing is true and correct.

Executed on 104 ZZ, 2003 date Vice President Engineering & Technical Services awh/

Attachments:

1. Description of Changes and Safety Evaluation
2. Annotated Technical Specification Pages
3. Bases Inserts

NOC-AE-03001487 Page 3 cc:

(paper copy) (electronic copy)

Ellis W. Merschoff A. H. Gutterman, Esquire Regional Administrator, Region IV Morgan, Lewis & Bockius LLP U.S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 L. D. Blaylock Arlington, Texas 76011-8064 City Public Service U. S. Nuclear Regulatory Commission Mohan C. Thadani Attention: Document Control Desk U. S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike R. L. Balcom Rockville, MD 20852 Texas Genco, LP Richard A. Ratliff A. Ramirez Bureau of Radiation Control City of Austin Texas Department of Health 1100 West 49th Street C. A. Johnson Austin, TX 78756-3189 AEP Texas Central Company Cornelius F. O'Keefe Jon C. Wood U. S. Nuclear Regulatory Commission Matthews & Branscomb P. O. Box 289, Mail Code: MN116 Wadsworth, TX 77483 C. M. Canady City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX 78704

NOC-AE-03001487 Attachment 1 ATTACHMENT 1 DESCRIPTION OF CHANGES AND SAFETY EVALUATION

NOC-AE-03001487 Attachment 1 Page 1 1.0 Introduction The proposed amendment will revise Technical Specification 3.3.2 to relax restrictive requirements associated with radiation monitoring for containment ventilation isolation (CVI). The proposed changes will enhance plant reliability by reducing its exposure to unnecessary shutdowns and increase operational flexibility. Inoperable radiation monitoring has little or no direct effect on plant safety and generally there are effective compensatory actions that can be taken for inoperable instrumentation.

The changes described below revise the changes proposed in the original submittal. As described in the cover letter, changes originally proposed for the reactor coolant system leakage detection system in Technical Specification 3.4.6.1 have been withdrawn.

The changes proposed for the radiation monitor actuation of CVI have been revised to apply only to the case where one of two channels of radiation monitoring actuation of CVI is inoperable. Time limits and required actions have been added to the case where one channel of radiation monitoring is inoperable and the containment purge isolation valves are under administrative control. Requirements for MODE 6 have been revised to reference TS 3/4.9.9 for Containment Ventilation Isolation during Refueling Operations.

2.0 Description Each of the proposed changes to the Technical Specifications is described in Table 1 below.

NOC-AE-03001487 Attachment 1 Page 2 Table 1 Page Affected 1 Description of Change Reason for Change I Section 3/4 3-26 Table 3.3-3, ACTION 18 specifies the action to be taken ACTION 18 was split into three ACTION when less than the minimum channels are actions to be able to separately STATEMENTS, operable for the functional units associated account for the functional units ACTION 18 for with Containment Ventilation Isolation. associated with Containment Functional Unit With less than the minimum channels Ventilation Isolation. This split 3.b.4 operable, the action currently allows allows the radiation monitoring operation to continue provided containment function to be handled separately and purge supply and exhaust valves are be made less restrictive. Allowing maintained closed. The proposed change the purge supply and exhaust valves breaks ACTION 18 into ACTION 18.a., to be open under administrative 18.b. and 18.c. ACTION 18.a. would apply control with one inoperable channel to automatic actuation logic and actuation of purge radioactivity-high provides relays and the requirements are unchanged for purge operations permitted by the from the current ACTION 18. ACTION TS while in this condition. One 18.b. 1 would apply to the RCB purge channel is still available for automatic radioactivity-high with one less than the actuation, routine RCB pressure minimum channels operable and establishes control evolutions are typically very a 30-day allowed outage time, after which brief and the likelihood of a the valves must be maintained closed. The coincident accident is very small. In ACTION is modified by a note that permits the event the operable channel fails, the supplementary purge supply and operators can quickly manually exhaust valves to be opened up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> initiate CVI from the handswitch in at a time in MODE 1 - 4 and either the Control Room. In MODE 1 - 4, supplementary purge or normal purge the SI actuation function is still valves to be open up to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> at a time in available for automatic isolation and MODE 5## provided administrative controls is the only actuation credited in the are in place. The note to Action 18.b.1 LOCA analyses.

would only apply during the 30-day allowed outage time. Action 18.b.2 applies when both radiation monitors are inoperable and retains the current TS action to close the purge isolation valves. Action 18.c. applies to MODE 6" and invokes the requirements of TS 3/4.9.9 for Containment Ventilation Isolation during Refueling Operations. It is modified by a note similar to the note for MODE 5##.

    1. - During CORE ALTERATIONS or movement of irradiated fuel within containment.

3/4 9-10 TS 3/4.9.9 A note complementary to the ACTION 18.c. The note is provided for consistency Containment note is added to permit either supplementary with the Note in proposed ACTION Ventilation or normal purge isolation valves to be open 18.c.

Isolation System for up to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> at a time provided administrative controls are in place.

NOC-AE-03001487 Attachment 1 Page 3

3.0 Background

STPNOC believes that the overall reliability of the plant can be enhanced by the elimination of unnecessarily restrictive TS requirements for radiation monitors. An overview of the basis for each of the proposed changes is described in Table 1, above.

4.0 Technical Analysis A technical review of each of the proposed changes described in Table 1 is provided below. The review identifies the affected instrumentation, describes its function, including relevant references to the STP UFSAR, and provides a technical justification for the proposed change.

STPNOC is not proposing the changes described in this application as risk-informed changes to be reviewed in conformance with the criteria of Regulatory Guides 1.174 and 1.177. Where risk information for initiating events is presented, it is clear that their likelihood is very small. In addition, the radiation monitors affected by the proposed changes are not modeled in the STP PRA so there is no detailed risk quantification.

STPNOC applied deterministic and risk insights to rank the affected radiation monitors as non-risk-significant.

Containment Ventilation Isolation (Table 3.3-3, ACTION 18 for Functional Unit 3.b.4)

The proposed change to the TS affects only the radiation monitoring instrumentation associated with the containment ventilation isolation function. The affected detectors and transmitters are RE/RT-8012 and RE/RT-80 13, which monitor containment normal and supplementary purge exhaust.

The STP UFSAR 7.3.1.1.2 description of the function of the instrumentation is provided below:

For the Containment ventilation isolation function, input is provided to the Westinghouse ESFAS from radiation detection equipment monitoring the Normal Containment Purge System exhaust line or the Supplementary Containment Purge System exhaust line. During a plant shutdown for refueling, the Normal Containment Purge System is in operation, as discussed in Section 9.4.5. Also discussed in the section is the Supplementary Containment Purge System, which may be used during nornal plant operation. Redundant Class E radiation monitors (i.e., the Reactor Containment Building [RCB] Purge Isolation) monitor the radiation in these purge lines, as discussed in Sections 11.5. Upon either monitor sensing radiation above a preset limit, a signal is sent to the logic trains of the Westinghouse ESFAS, and the Containment ventilation isolation signal is actuated.

NOC-AE-03001487 Attachment 1 Page 4 The 48" Normal Purge valves are required to be sealed closed in MODE 1, 2, 3, and 4. In a LOCA, both Normal and Supplementary purge lines are isolated by a Safety Injection (SI) signal, which is unaffected by this proposed change. Actuation of the purge isolation by these radiation monitors is not credited in the LOCA accident analyses, and is only a backup function for this event.

Either Supplementary Purge or Normal Purge may be operated in MODE 5 and 6. The subject radiation monitors are credited for purge line isolation for a fuel handling accident.

STPNOC's proposed ACTION 18.b. affects the current TS action that requires the purge to be isolated when one of the two required channels is inoperable. ACTION 18.b.1 is the proposed action with one inoperable channel and would establish a 30-day restoration time in MODE 1 - 4, and MODE 5". A note to ACTION 18.b. 1 is proposed to allow the supplementary purge valves to be opened in MODE 1-4 under administrative control during the 30-day allowed outage time to permit operation of the supplementary purge system for up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at a time for the evolutions permitted by the Technical Specifications (containment pressure control, ALARA and respirable air quality needed for personnel entry into containment and for surveillance tests that required the valves to be open). The most common application is for containment pressure control, where purges are generally of short duration (less than an hour). This provision would remove a potentially burdensome requirement to maintain the purge valves closed for a situation where a purge was needed at the same time one channel of the radiation monitors was inoperable. Not being able to purge to control containment pressure could result in application of ACTION for Technical Specification 3.6.1.4, which has a 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> shutdown requirement.

The likelihood of an event that would cause a significant radioactive release in the containment requiring containment isolation occurring during a purge activity is very small (lE-07/yr.). In MODE 1 - 4, the safety analysis credits only the SI signal for actuation of CVI. As a backup, the operable radiation monitoring channel would still be available to actuate containment isolation. Administrative control during purge evolutions with an inoperable radiation monitoring channel would include the operator ability to manually initiate CVI from the control room handswitch and typically include an assessment of plant conditions for potential actuation precursors, monitoring containment radiation and limiting purge duration. The current TS action only requires that the isolation valves be maintained closed and does not prescribe a restoration time.

STPNOC selected 30 days based on the time being a reasonable time to restore a non-risk-significant function that is readily accessible at power.

ACTION 18.b. 1 would also apply in MODE 5## to address the possibility of a fuel handling accident while moving fuel in the In Containment Storage Area. While STP has the design capability to store and move fuel in the ICSA in this MODE, it is not currently

NOC-AE-03001487 Attachment 1 Page 5 used. The note described above would allow the valves to be open for up to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> at a time in MODE 5##.

ACTION 18.b.2 is proposed for MODEs 1 - 4 and MODE 5## when both channels of RCB Radioactivity - High are inoperable. This action requires the purge isolation valves to be maintained closed and is consistent with the requirements of the current TS. There is no provision in this action for opening the valves to perform RCB purges.

ACTION 18.c. would apply in MODE 6##. STPNOC proposes to revise the specification to reference TS 3/4.9.9, which specifies the requirements for Containment Ventilation Isolation during refueling operations. The most significant effect of this change will be that TS 3/4.9.9 requires closure of the penetration, which may be accomplished with the use of only one valve in each penetration. The current RCB Radiation - High specification would require both valves in each penetration to be closed. The design function is maintained with the penetration closed with a single valve. This change will ensure consistency within the Technical Specifications. A note is proposed to be added to both proposed ACTION 18.c and TS 3/4.9.9 to permit purges for up to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> at a time for the case of a single inoperable channel of RCB Radioactivity - High.

In MODE 5" and 6##, there is no credible LOCA event and the design basis postulated event is a fuel handling accident in containment. Both are modified by a note that would allow the either the Supplementary or Normal Purge supply and exhaust valves to be open up to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> at a time for required purge operations. The longer duration is justified because the design basis fuel handling accident in these MODEs would be expected to be a slower developing event and purge operations in support of shutdown or refueling activities are typically much longer than those done at power. As noted above, the operable channel of radiation monitoring would still be available to isolate containment purge and the same administrative controls would be effective in responding to a high radiation signal.

Loss of power supply to the output ESF relays of either channel of these monitors will be considered inoperable actuation logic and the isolation valves will be maintained closed in accordance with proposed ACTION 18.a. This is because this failure mode will result in the inability of the other actuation signals to close the purge valves if the initial signal is reset. The procedurally required administrative control would also compensate for the inoperable channel by requiring appropriate limitations on the purge duration and operator monitoring of radiation levels during the evolution. The administrative controls will be described in the Bases for the TS. STPNOC will provide revised Bases pages incorporating the information in Attachment 3 subsequent to NRC approval of the proposed change.

STPNOC proposes to add a note to TS 3/4.9.9 that complements the note in ACTION 18.c. This is an administrative change to assure consistency in the requirements.

NOC-AE-03001487 Attachment 1 Page 6 STPNOC notes that the justification above demonstrates that the probability of a core damage event during RCB pressure control purges is very small and that there are compensatory actions that maintain adequate defense in depth.

5.0 Regulatory Safety Analysis 5.1 No Significant Hazards Determination STPNOC has evaluated whether or not a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10CFR50.92, "Issuance of amendment," as discussed below.

1) Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?

Response: No.

The radiation monitors affected by the proposed amendment are not potential accident initiators. Adequate measures are available to compensate for instrumentation that is out of service. The proposed amendment does not affect how the affected instrumentation normally functions or its role in the response of an operator to an accident or transient. The core damage frequency in the STP PRA is not impacted by the proposed changes. Therefore, STPNOC concludes that there is no significant increase in the probability or consequences of an accident previously evaluated.

2) Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?

Response: No.

The instrumentation affected by the proposed amendment is not credited for the prevention of any accident not evaluated in the safety analysis. The proposed amendment involves no changes in the way the plant is operated or controlled. It involves no change in the design configuration of the plant. No new operating environments are created. Therefore, STPNOC concludes the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

NOC-AE-03001487 Attachment 1 Page 7

3) Does the proposed change involve a significant reduction in a margin of safety?

Response: No.

The proposed change has no significant effect on functions that are supported by the affected instrumentation. There will be no significant effect on the availability and reliability of the affected instrumentation. Adequate measures are available to compensate for instrumentation that is out of service. Therefore, STPNOC concludes the proposed change does not involve a significant reduction in the margin of safety.

Conclusion Based upon the analysis provided herein, the proposed amendments will not increase the probability or consequences of an accident previously evaluated, create the possibility of a new or different kind of accident from any accident previously evaluated, or involve a reduction in a margin of safety. Therefore, the proposed amendments meet the requirements of 10 CFR 50.92 and do not involve a significant hazards consideration.

5.2 Applicable Regulatory Requirements/Criteria Containment Ventilation Isolation Actuation:

The 48-inch normal containment purge lines are sealed closed during operating conditions other than cold shutdown and refueling. The supplementary containment purge system may be used during normal plant operation (operating modes 1 through 4).

Normal and supplementary purge system isolation valves are designed to close on receipt of a containment ventilation isolation signal. This signal is initiated by the following:

safety injection signal, containment phase A isolation manual actuation, containment spray manual actuation, and high containment purge radiation.

The radiation monitor function to isolate containment ventilation meets the requirements of NUREG-0737 Item II.E.4.2, SRP Section 6.2.4, and BTP CSB 6-4.

The radiation monitor actuation of the containment ventilation system is an ESFAS function and is subject to the requirements of GDC 2, 4, 20 through 24, and 10 CFR 50.55a(h).

The proposed changes to the Technical Specifications would not change the function of the affected radiation monitors and there is no significant impact on compliance with the regulatory requirements.

NOC-AE-03001487 Attachment 1 Page 8 6.0 Environmental Considerations 10 CFR 51.22(b) specifies the criteria for categorical exclusions from the requirements for a specific environmental assessment per 10 CFR 51.21. This amendment request meets the criteria specified in 10 CFR 51.22(c)(9). The specific criteria contained in this section are discussed below.

(i) the amendment involves no significant hazards consideration As demonstrated in the No Significant Hazards Consideration Determination, the requested license amendment does not involve any significant hazards consideration.

(ii) there is no significant change in the types or significant increase in the amounts of any effluents that may be released offsite The requested license amendment involves no change to the facility and does not involve any change in the manner of operation of any plant systems involving the generation, collection or processing of radioactive materials or other types of effluents. Therefore, no increase in the amounts of effluents or new types of effluents would be created.

(iii) there is no significant increase in individual or cumulative occupational radiation exposure The requested license amendment involves no change to the facility and will not increase the radiation dose resulting from the operation of any plant system. Furthermore, implementation of this proposed change will not involve work activities that could contribute to occupational radiation exposure. Therefore, there will be no increase in individual or cumulative occupational radiation exposure associated with this proposed change.

Based on the above it is concluded that there will be no impact on the environment resulting from this change. The change meets the criteria specified in 10 CFR 51.22 for a categorical exclusion from the requirements of 10 CFR 51.21 relative to specific environmental assessment by the Commission.

7.0 References

1. South Texas Project Updated Final Safety Analysis Report

NOC-AE-03001487 Attachment 2 ATTACHMENT 2 PROPOSED TECHNICAL SPECIFICATION CHANGES

NO CHANGES TO THIS PAGE -

PROVIDED FOR REFERENCE NOC-AE-0300 1487 Attachment 2 Page 1 TABLE 3.3-3 (Continued)

ENGINEERED SAFETY FEATURES ACTUATION SYSTEM INSTRUMENTATION MINIMUM TOTAL NO. CHANNELS CHANNELS APPLICABLE FUNCTIONAL UNIT OF CHANNELS TO TRIP OPERABLE MODES ACTION

3. Containment Isolation (Continued)
b. Containment Ventilation Isolation
1) Automatic Actuation Logic 2 1 2 1,2,3,4 18
2) Actuation Relays*** 3 2 3 1,2,3,4 18
3) Safety Injection *** See Item 1. above for all Safety Injection initiating functions and requirements.
4) RCB Purge 2 1 2 1,2,3,4,5##, 18 w Radioactivity- High 6##

0z 5) Containment Spray- See Item 2. above for Containment Spray manual initiating functions and requirements.

Manual Initiation

6) Phase "A" Isolation- See Item 3.a. above for Phase "A" Isolation manual initiating functions and requirements.

Manual Isolation

c. Phase "B" Isolation
1) Automatic Actuation Logic 2 1 2 1,2,3,4 14
2) Actuation Relays 3 2 3 1,2,3,4 14
3) Containment Pressure -- 4 2 3 1,2,3 17 High-3
4) Containment Spray-- See Item 2. above for Containment Spray manual initiating functions and requirements.

Manual Initiation

d. RCP Seal Injection Isolation
1) Automatic Actuation Logic 1 1 1 1,2,3,4 16 and Actuation Relays 03 a

NOC-AE-03001487 Attachment 2 Page 2 TABLE 3.3-3 (Continued)

TABLE NOTATIONS

      • Function is actuated by either actuation train A or actuation train B.

Actuation train C is not used for this function.

        • Automatic switchover to containment sump is accomplished for each train using the corresponding RWST level transmitter.
  1. Trip function may be blocked in this MODE below the P-1 1 (Pressurizer Pressure Interlock)

Setpoint.

    1. During CORE ALTERATIONS or movement of irradiated fuel within containment.
      1. Trip function automatically blocked above P-1 1 and may be blocked below P-1 1 when Low Compensated Steamline Pressure Protection is not blocked.

ACTION STATEMENTS ACTION 14- With the number of OPERABLE channels one less than the Minimum Channels OPERABLE requirement, restore the inoperable channel to OPERABLE status within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in COLD SHUTDOWN within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />; however, one channel may be bypassed for up to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> for surveillance testing per Specification 4.3.2.1, provided the other channel is OPERABLE.

ACTION 15- (Not Used)

ACTION 16- With the Charging Header Pressure channel inoperable:

a) Place the Charging Header Pressure channel in the tripped condition within one hour and b) Restore the Charging Header Pressure channel to operable status within 7 days or be in at least Hot Standby within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

ACTION 17- With the number of OPERABLE channels one less than the Total Number of Channels, place the inoperable channel in the bypassed condition within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, or be in at least HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in at least HOT SHUTDOWN within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />. One additional channel may be bypassed for up to 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> for surveillance testing per Specification 4.3.2.1.

L__ _l_ _ A1 _

ACTION 18- y Vitn less tan tne Minimum unannels uPER:BLL requiremeni. operation may continuo providod eth containment purgo supply and exhlaust valvos arc maintained closep.

INSERT 1 SOUTH TEXAS - UNITS 1 & 2 3/4 3-26 Unit 1 - Amendment No. -r,4 436 Unit 2 - Amendment No. 425

NOC-AE-03001487 Attachment 2 Page 3 INSERT 1:

a) With less than the Minimum Channels OPERABLE requirement for Automatic Actuation Logic or Actuation Relays, operation may continue provided the containment purge supply and exhaust valves are maintained closed.

b) MODE1,2,3,4,or5"':

1. With one less than the Minimum Channels OPERABLE requirement for RCB Purge Radioactivity-High, within 30 days restore the inoperable channel or maintain the containment purge supply and exhaust valves closed.

NOTE:

MODE 1, 2, 3, or 4: Supplementary containment purge supply and isolation valves may be open during the allowed outage time for up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at a time for required purge operation provided the valves are under administrative control.

MODE 5##: Supplementary or Normal containment purge supply and isolation valves may be open during the allowed outage time for up to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> at a time for required purge operation provided the valves are under administrative control.

2. With two less than the Minimum Channels OPERABLE requirement for RCB Purge Radioactivity-High, operation may continue provided the containment purge supply and exhaust valves are maintained closed.

c) MODE 6##: With less than the Minimum Channels OPERABLE requirement for RCB Purge Radioactivity - High, apply the requirements of Technical Specification 3.9.9 for an inoperable Containment Ventilation Isolation System.

NOTE:

With one less than the Minimum Channels Operable requirement for RCB Purge Radioactivity-High, Supplementary or Normal containment purge supply and isolation valves may be open for up to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> at a time for required purge operation provided the valves are under administrative control.

NOC-AE-03001487 Attachment 2 Page 4 REFUELING OPERATIONS 3/4.9.9 CONTAINMENT VENTILATION ISOLATION SYSTEM LIMITING CONDITION FOR OPERATION 3.9.9 The Containment Ventilation Isolation System shall be OPERABLE.

APPLICABILITY: During CORE ALTERATIONS or movement of irradiated fuel within the containment.

ACTION:

a. With the Containment Ventilation Isolation System inoperable, close each of the purge and exhaust penetrations providing direct access from the containment atmosphere to the outside atmosphere.

L

¢NIOTE.'

inaccJrdance wCit1hACTION-18.b andATION 18.c.,

Supplementary or Normal containment purge supply and isolation valves-may be open for up'to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> at a time for required 'purge pperationprovided the valves are underadministrative control.

b. The provisions of Specification 3.0.3 are not applicable.

SURVEILLANCE REQUIREMENTS 4.9.9 The Containment Ventilation Isolation System shall be demonstrated OPERABLE within 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> prior to the start of and at least once per 7 days during CORE ALTERATIONS by verifying that containment ventilation isolation occurs on manual initiation and on a High Radiation test signal from each of the RCB purge radiation monitoring instrumentation channels.

SOUTH TEXAS - UNITS 1 & 2 3/4 9-10

NOC-AE-03001487 Attachment 3 Page 1 Bases Inserts The information below will be incorporated in the Technical Specification Bases for the RCB Purge Radioactivity - High.

During a plant shutdown for refueling, the Normal Containment Purge System is in operation.

The Supplementary Containment Purge System may be used during normal plant operation.

Redundant Class E radiation monitors (i.e., the Reactor Containment Building [RCB] Purge Isolation) monitor the radiation in these purge lines. Upon either monitor sensing radiation above a preset limit, a signal is sent to the ESFAS logic trains, and the Containment ventilation isolation signal is actuated. In a LOCA, both Normal and Supplementary purge lines are isolated by a Safety Injection (SI) signal. Actuation of the purge isolation by these radiation monitors is not credited in the LOCA accident analyses, and is only a backup function for this event. The subject radiation monitors are credited for purge line isolation for a fuel handling accident.

ACTION 18.a. applies when the actuation logic for RCB Purge Radioactivity - High is inoperable because it affects both channels. The required action is to maintain the isolation valves closed. Loss of power supply to the output ESF relays of either channel of these monitors will be considered inoperable actuation logic and the isolation valves will be maintained closed in accordance with proposed ACTION 18.a. This is because this failure mode will result in the inability of the other actuation signals to close the purge valves if the initial signal is reset.

In MODE 1, 2, 3, 4, or 5tt, when one of the two required channels of RCB Purge Radioactivity -

High is inoperable, ACTION 18.b.1 requires restoration within 30 days. The allowed outage time is a reasonable time for easily accessible non-risk-significant instrumentation. The required action is modified by a note that allows the supplementary purge valves to be opened in MODE 1-4 under administrative control during the 30-day allowed outage time to permit operation of the supplementary purge system for up to 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> at a time for the evolutions permitted by the Technical Specifications (containment pressure control, ALARA and respirable air quality needed for personnel entry into containment and for surveillance tests that required the valves to be open). The 2-hour allowance is adequate time for the routine pressure control purge operations during power operation. The note also allows the normal or supplementary purge supply and exhaust valves to be open up to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> at a time in MODE 5## for required purge operations. The 6-hour duration is justified because the design basis event in this MODE would be expected to be a slower developing event and purge operations in support of refueling activities are typically much longer than those done at power. Opening the valves for purge operations is not permitted after the 30-day allowed outage time has expired.

In MODE 1 - 4, the safety analysis credits only the SI signal for actuation of CVI. As a backup, the operable radiation monitoring channel would still be available to actuate containment isolation. In MODE 5 and 6, there is no credible LOCA event and the design basis postulated event is a fuel handling accident in containment.

NOC-AE-03001487 Attachment 3 Page 2 Bases Inserts Administrative control during purge evolutions with an inoperable radiation monitoring channel would include the operator ability to manually initiate CVI from the control room handswitch and typically include an assessment of plant conditions for potential actuation precursors, monitoring containment radiation and limiting purge duration.

ACTION 18.b.2 applies in MODE 1, 2, 3, 4, and 5## when both channels of RCB Purge Radioactivity - High are inoperable. The action requires the purge isolation valves to be maintained closed and there is no provision for purge operation under administrative control.

ACTION 18.c. applies to the condition where one or both RCB Purge Radioactivity - High channels are inoperable in MODE 6 during movement of irradiated fuel or CORE ALTERATIONS. The ACTION directs the user to apply the requirements of TS 3/4.9.9 for an inoperable Containment Ventilation Isolation System during Refueling. With one inoperable channel of RCB Purge Radioactivity - High inoperable, the action includes a provision that allows purge operations for up to 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> at a time. The basis for the 6 hour6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> duration of the purge is the same as described above for MODE 5 #.

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