B16312, Application for Amend to License DPR-21,by Incorporating Changes Representing Revs to TS Tables 3.1.1,3.2.1,3.2.2, 3.2.3,Section 3.2.D.2 & Section 3.7/4.7.C

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Application for Amend to License DPR-21,by Incorporating Changes Representing Revs to TS Tables 3.1.1,3.2.1,3.2.2, 3.2.3,Section 3.2.D.2 & Section 3.7/4.7.C
ML20136B315
Person / Time
Site: Millstone Dominion icon.png
Issue date: 03/06/1997
From: Mcelwain J
NORTHEAST NUCLEAR ENERGY CO.
To:
Shared Package
ML20136B320 List:
References
B16312, NUDOCS 9703100240
Download: ML20136B315 (17)
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Waterford. CT 00E-0128 (860) 447-1791 Fax (800) 444-4277 The Northeast Utilities System F WR 6 1997 l Docket No. 50-245 B16312 I

Re: 10CFR50.90 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 i l

Millstone Nuclear Power Station, Unit No.1 Proposed Technical Soecification Revision - Allowable Outaae Times Pursuant to 10CFR50.90, Northeast Nuclear Energy Company (NNECO) hereby proposes to amend its Facility Operating License, DPR-21, by incorporating the attached proposed changes into the Technical Specifications of Millstone Nuclear Power Station, Unit No.1. j l

The proposed Technical Specification changes contained herein represent revisions to 1 Technical Specification Table 3.1.1, " Reactor Protection System (Scram) instrumentation Requirements," Table 3.2.1, " instrumentation That initiates Primary l Containment isolation Functions," Table 3.2.2, " Instrumentation That initiates and Controls the Emergency Core Cooling Systems," Table 3.2.3, " Instrumentation That initiates Rod Block," Section 3.2.D.2, " Air Ejector Off-Gas System," Section 3.7/4.7.C,

" Secondary Containment," and associated bases. The existing Technical Specifications for instrumentation that initiates actions and secondary containment limiting conditions for operation and surveillance requirements will be improved by: '

a) adding allowable outage times (AOT) for instrumentation that automatically initiates actions such as reactor scram and primary containment isolation valve closure; b) incorporating an editorial change to Note 1 for Table 3.2.2; c) adding an AOT for the air ejector off-gas system radiation monitors; d) delineating required actions and including an AOT for continued plant operation while restoration of secondary containment integrity is underway; and el adding a periodic surveillance requirement for reactor building access ways.

The two-hour instrumentation AOT included in this amendment request is developed from the Standard Technical Specifications, NUREG-0123, " Standard Technical Specifications for General Electric Boiling Water Reactors (BWR/5)f Revision 3 and the improved Standard Technical Specifications, NUREG-1433, "Sbndard Technical Specifications fgGgeral Electric Plants (BWR/4)," Revision 1.

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U.S. Nuclear R:gulatory Commission i B16312\Page 2 Attachment 1 of this letter provides supporting information and the safety assessment of the proposed chango. Attachment 2 is the determination of no significant hazards considerations. Attachment 3 is the marked-up version of the current Technical Specifications. Attachment 4 is the retyped Technical Specification pages.

NNECO has reviewed the proposed Technical Specification changes in accordance with 10CFR50.92 and concludes that the proposed changes do not involve a significant hazards consideration. NNECO has also reviewed the proposed license amendment against the criteria of 10CFR51.22 for environmental considerations and concludes that the proposed changes will not increase the types and amounts of effluents that may be released offsite, and will not significantly increase the individual or cumulative occupational radiation exposures. Thus, NNECO concludes that the proposed changes are eligible for categorical exclusion from the requirements for an environmental impact statement in accordance with 10CFR51.22(c)(9).

The Plant Operations Review Committee and the Nuclear Safety Assessment Board have reviewed the proposed changes to the Technical Specifications and concur with the above determinations. Pursuant to 10CFR50.91(b)(1), Millstone Unit No.1 is providing a copy of this license amendment request and the associated analysis regarding a no significant hazards consideration to the appropriate State of Connecticut representative. These Technical Specification changes are required to support fuel reload. Therefore, approval is requested by May 15, 1997. NNECO requests that NRC issue a license amendment which will be effective upon issuance and shall be implemented within 90 days of issuance. This latitude permits appropriate procedural and program revisions and training necessary to implement the proposed changes.

The Technical Specification bases for Section 3.7 do not reflect changes proposed in the Millstone Unit No.1 submittal for " Standby Gas Treatment System," dated December 7,1995, for page B 3/4 7-6.

Should you have any questions or comments regarding this transmittal, please contact Mr. R. W. Walpole at (860) 440-2191.

Very truly yours, NORTHEAST NUCLEAR ENERGY COMPANY

$Yba 4f6hn P. McElwaiq(

Millstone Unit No.1 Recovery Officer cc: See Page 3 I

l , _ <. I U.S. Nucl:tr Rrgulatory Commission B16312\Page 3 Subscribed and sworn to before me I this d day of MkkI .1997.

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fus l Date Commission Expires: J$he M 2 00/

i j Attachments l

l cc: H. J. Miller, Regional Administrator, Region 1

! T. A. Eastick, Senior Resident inspector, Millstone Unit No.1

{ S. Dembek, Project Manager, Millstone Unit No.1 Dr. W. D. Travers, Director, Special Projects Kevin T. A. McCarthy, Director Bureau of Air Management Monitoring and Radiation Division Department of Environmental Protection 79 Elm Street Hartford, CT 06106-5127 l

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i Docket No. 50-245 B16312 a

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j Attachment 1 Millstone Nuclear Power Station, Unit No.1 1

Proposed Technical Specification Revision '

Allowable Outage Times j

Supporting Information and Safety Assessment of Proposed Changes i

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March 1997

. U.S. Nucl=r R:gulatory Commission B16312\ Attachment 1\Page 1 1

Millstone Nuclear Power Station, Unit No.1 Proposed Technical Specification Revision Allowable Outage Times Supporting Information and Safety Assessment of Proposed Changes INTRODUCTION A self assessment performed on Millstone Unit No.1 Technical Specifications (TS),

1 determined that performance of certain surveillances and preventive maintenance may result in short periods when protective instrumentation is inoperable and the TS require tripping of the initiation logic associated with the instrumentation to be tested. The proposed changes are developed using the guidance provided in Standard Technical Specifications, NUREG-0123, " Standard Technical Specifications for General Electric Boiling Water Reactors (BWR/5)," Revision 3, and improved Standard Technical Specifications, NUREG-1433, " Standard Technical Specifications General Electric Plants BWR/4," Revision 1. However, NUREG-1433 does not contain an Allowable j Outage Time (AOT) for performance of surveillances associated with the air ejector off-gas system radiation monitors. A plant specific evaluation must be performed in order to fully implement further relaxations pertaining to allowable outage times allowed by NUREG-1433.

Additionally, other testing and maintenance may result in the secondary containment not being in compliance with the TS. The Containment Systems Limiting Condition for Operation (LCO) does not specify an AOT for restoration of secondary containment. In addition, no surveillance requirement currently exists to periodically confirm that at least one door in each of the double-doored accesses to the secondary containment is closed.

The proposed amendment is designed to eliminate the above identified weaknesses by adopting appropriate guidelines pertaining to protective instrumentation from NUREG-0123 and NUREG-1433, and reactor building access control from NUREG-1433.

DESCRIPTION OF PROPOSED CHANGES Add a two-hour Allowable Outage Time (AOT) for instrumentation that automatically initiates: reactor protection system actuation (Table 3.1.1, Note 1), primary containment isolation valve closure (Table 3.2.1, Note 1), emergency core cooling system initiation (Table 3.2.2, Note 1), and control rod withdrawal block (Table 3.2.3, Note 1).

Incorporate an editorial change to Note 1 for Table 3.2.2, i.e., change "may" to "shall".

U.S. Nuctur Regulatory Commission B16312\ Attachment 1\Page 2 Add a two-hour AOT to Specification 3.2.D.2, Air Ejector Off-Gas System for the radiation monitors.

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Delineate required actions and include an AOT for continued plant operation while  !

i restoration of secondary containment integrity is underway (Specification 3.7.C.2.a).

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Provide a new monthly surveillance requirement for reactor building access ways  ;

4 (Surveillance Requirement 4.7.C.1.b). I

! l Revise associated TS bases.

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! 1 l SAFETY ASSESSMENT j Protective Instrumentation Allowable Out of Service Times l

l Based on the NUREG-0123 protective instrumentation guidelines and the current

! Millstone Unit No.1 bases for Sections 3.1 and 3.2 ("When necessary, one channel i may be made inoperable for brief intervals to conduct required functional tests and j calibrations."), a note for the protective instrumentation tables which contain the  ;

i minimum number of operable instrumentation channels per trip system is proposed to be revised. The change adds a two-hour period which defines in the Technical i Specifications (TS) the "brief interval" mentioned in the bases during which a channel i may be inoperable without placing the trip system in the tripped condition, provided the

associated trip function maintains trip capability. The original Technical Specification 4

Bases submitted as part of the application for Millstone Unit No.1's Provisional

Operating License (dated October 7, 1970) included this recognition that
instruments would be inoperable during required functional tests and calibrations.
As such, it was recognized in the original licensing basis and remains part of the current licensing basis of the plant, i

i TS require a minimum number of channels of protective instrumentation in each trip l

system to be either operable or tripped. They also require periodic surveillance testing of these protective instrumentation channels to demonstrate their operability.

Surveillance testing causes the channel being tested to be inoperable during

! performance of the surveillance tests. Therefore, the channel under test cannot be j relied upon to perform its safety function. Verbatim compliance with the current

Technical Specifications permit making an instrument inopeeble for testing, but do not I

explicitly allow exemption from the required actions in this condition.

! The proposed changes provide an allowance to not place a channel's associated trip

system in the tripped condition for up to two hours during the performance of required j surveillances, as long as the associated function maintains trip capability. For those i trip systems with only one channel per trip system, this situation is not applicable.

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U.S. Nuclacr Regulatory Commission B16312\ Attachment 1\Page 3 Existing TS LCO and Surveillance sections and tables do not specify a time delay for entry into the associated LCO when testing the ascaciated instruments. TS bases state, "When necessary, one channel may be mde inoperable for brief intervals to conduct required functional tests and calibrapons ... ." The proposed TS define a "brief interval" as two hours and explicitly permit a delay in entering the actions for this period. This change is required since entering the corresponding LCO when testing these instruments would prevent compliance with existing TS definitions for Instrument Functional Test and Instrument Calibration "to verify proper instrument channel response, alarm, and/or initiating action" or

" encompass the entire instrument including actuation, alarm or trip" respectively. l The alarms and trips cannot be tested if the other channel in the division is in the tripped condition. Similarly, the existing requirement for the Instrument Functional Test to include initiating action could not be satisfied if the LCO condition of tripping the inoperable channel was performed.

Tripping a channel to perform surveillance testing required by TS increases the susceptibility to inadvertent trips, scrams, transients, and challenges to safety systems l if a spurious trip signal occurs in the coincident trip system. However, reliance on one remaining operable channel in the same trip system does not prevent the required protective actions from being initiated (assuming no single failure) if a trip setpoint is exceeded during a surveillance test while the redundant channel is being tested. The allowable out of service time interval of two hours for performance of surveillances is small in comparison with a normal operating cycle so that the impact on the safety i function of the affected trip system is relatively insignificant. Therefore, not placing a trip system in the tripped condition for the proposed allowable out of service time will have a negligible effect on the reliable operation of the protective systems and will l decrease the likelihood of inadvertent trips, scrams, transients, and challenges to safety systems.

Since no specific guidance is provided defining "brief intervals" nor any plant specific analysis performed, a two-hour allowance for testing is judged acceptable based upon:

  • Remaining capability to trip. Testing of one sensor does not render the trip system inoperable, but, rather, simply increases the single failure vulnerability of one trip function in one trip system. Inoperabilities affecting diverse trip functions would require multiple failures.
  • Diversity of sensors available to provide the trip signals. Surveillance testing is not performed on multiple variables' sensors simultaneously; so other trip functions either remain operable or were previously declared inoperable and placed in a tripped condition.

U.S. Nucirr Regulttory Commission B16312\ Attachment 1\Page 4 Low probability of an event requiring the initiation of a scram during this time frame.

  • Reasonable test interval. The two-hour test duration provides a reasonable amount of time for testing without placing undo time constraints on maintenance personnel.

Two-hour time interval is consistent with GE BWR Standard Technical Specifications (NUREG-0123).

e Two hours represents one half of the required action completion time

. (four hours) associated with an inoperable RPS trip function.

Existing Note 1 for Table 3.2.2 states "If the first column cannot be met for one of the
trip systems, that system may be tripped." The proposed change substitutes "shall" for "may" to reflect that this is a requirement, not an option. Additionally, this will provide consistency with similar notes (e.g., Note 3 for Table 3.2.1).

The two-hour instrumentation AOT for the Air Ejector Off-Gas System radiation monitors is slightly less restrictive than the one hour allowed by NUREG-0123. Since this requirement was relocated from NUREG-1433, there is no corresponding requirement for comparison. These radiation monitors are arranged in a two-out-of-two logic; therefore, both must trip to initiate the required action (closure of the off-gas isolation valve to the main stack). This action, however, is automatically delayed by 15 l minutes. A high radiation condition sensed by the monitor in service would provide  ;

sufficient time to take corrective actions. Since a two-hour AOT is deemed acceptable for instrumentation in systems such as the Reactor Protection System and Emergency Core Cooling System, it is appropriate to apply a two-hour AOT to these radiation monitors.

TS 3.2.D.2 " Air Ejector Off-Gas System" and TS 3/4.8.B.1 " Radioactive Gaseous Effluent Monitoring Instrumentation" both apply to the air ejector off-gas radiation monitors. NNECO recognizes that inconsistencies exist between the two TS with respect to the applicabilities, actions, and surveillance requirements. These inconsistencies do not preclude compliance and will be resolved when Millstone Unit No.1 converts to improved Technical Specifications based on NUREG-1433. In the interim, it is NNECO's intention that administrative controls, such as the Technical Requirements Manual, be used to provide clarification that ensures compliance with both specifications.

U.S. Nucl=r Rtgulatory Commission

] B16312\ Attachment 1\Page 5

! Secondarv Containment Based on the NUREG-1433 and on existing Millstone Unit No. 1 Technical Specification restrictions associated with secondary containment integrity, the operating conditions under which access controls are explicitly required in the current TS are as follows:

1) when in RUN, STARTUP/ HOT STANDBY or HOT SHUTDOWN, or 4
2) when moving the fuel cask, irradiated fuel or other loads in containment which have the potential for causing a significant release of fission products, or
3) when performing CORE ALTERATIONS or operations with a potential for
draining the reactor vessel when the vessel contains irradiated fuel.

l For the RUN, STARTUP/ HOT STANDBY or HOT SHUTDOWN operating conditions of

1) above, the AOT statement in the proposed amendment and current TS applicability
are consistent with the action on loss of secondary containment integrity for j NUREG-1433 and the applicability is consistent with NUREG-1433, i.e., Modes 1,2, i and 3. The proposed TS requires restoration of secondary containment within four hours or be in a condition (e.g., COLD SHUTDOWN) where secondary containment is

, not required within the succeeding 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

For the operating conditions of 2) and 3) above, the proposed AOT is not applicable and activities are suspended immediately. This statement is consistent with j NUREG-1433. The new access control surveillance requirement (SR 4.7.C.1.b) proposed will enhance overall secondary containment assurance during periods requiring ~ operability. This change is consistent with NUREG-1433.

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Docket No. 50-245 B16312 Attachment 2 Millstone Nuclear Power Station, Unit No.1 Proposed Technical Specification Revision Allowable Outage Times Determination of No Significant Hazards Consideration i

1 March 1997 i

E---a, U.S. Nucler R:gulttory Commission B16312\ Attachment 2\Page 1 Millstone Nuclear Power Station, Unit No.1 Proposed Technical Specification Revision Allowable Outage Times Determination of No Significant Hazards Consideration Pursuant to 10CFR50.92, NNECO has reviewed the proposed changes and concludes that the changes do not involve a significant hazards consideration since the proposed changes satisfy the criteria in 10CFR50.92(c).

1. The operation of Millstone Nuclear Power Station. Unit No.1. in accordance with the proposed amendment. will not involve a sionificant increase in the probability or conseouences of an accident previously evaluated.

The inherent redundancy and reliability of the protective instrumentation trip systems ensure that the consequences of an accident are not significantly increased. In addition, the restrictive Allowable Outage Time (AOT) interval limits the probability of the protective instrument channel being unavailable and an accident requiring its function from occurring simultaneously. The requirement that the associated trip function maintains trip capability ensures that the protective instrumentation response will occur such that the consequences of an accident are not different from those previously evaluated.

Instruments addressed in the proposed TS respond to changes in the plant.

The proposed (AOTs) provide a two-hour interval where the instrument is inoperable, yet the Technical Specification (TS) Limiting Condition for Operation (LCO) action statement is not immediately entered. The probability of a plant transient being initiated by a trip of a coincident channel during surveillance testing is reduced since the channel under test will only be tripped for a small portion of the test interval. Therefore, AOTs provided by the proposed TS have no effect on the probability of occurrence of previously evaluated accidents.

The proposed TS changes provide a two-hour interval where the instrument i is inoperable, but the TS LCO action statement is not immediately entered. j If a single failure occurred on the other channel of the trip system being tested and the channel being tested was not in the trip condition, a valid signal might not provide the required protective action. The probability of  !

an event requiring initiation of the protective function within the proposed AOT is low. Additionally, surveillance testing is not generally performed on multiple sensors simultaneously. So, other trip functions and sensors remain operable and the probability of extensive inoperabilities affecting diverse trip functions is low. A spurious trip of a coincident channel could 1

U.S. Nucl2cr Regulatory Commission
B16312\ Attachment 2\Page 2 '

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initiate a plant transient (for example, a reactor scram or a main steam

Isolation valve closure); however, these transients are bounded by the +

current analyses. Moreover, the original TS bases submitted as part of the application for Millstone Unit No.1's Provisional Operating License (dated

October 7,1970) included recognition that instruments would be inoperable 4

during required functional tests and calibrations. Thus, these conditions j were recognized in the original design bases and constitute part of the i licensing bases of the plant. NUREG-0123 provided specific time frames and the AOTs addressed in the table notes and specific action statements. ,

Millstone Unit No.1 AOT values chosen are consistent with these values j and less than those approved in NUREG-1433 which had a more detailed j study performed to lengthen the AOT value.

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The existing TS definition for Instrument Functional Test would be difficult to satisfy if the LCO condition of tripping the inoperable channel was performed. A similar problem of complying with the Instrument Calibration definition also exists. The TS requirement to perform functional tests and calibrations is not consistent with a requirement to trip the system under test. The proposed TS changes permit more complete functional and calibration testing. For example, the main scram contactors could be included within the surveillance tests. Therefore, these TS clarifications do not increase the consequences of any previously analyzed accidents.

The two-hour instrumentation AOT for the Air Ejector Off-Gas System radiation monitors is slightly less restrictive than that allowed by the NUREG-0123. Since this requirement was relocated from NUREG-1433, there is no corresponding requirement for comparison. These radiation monitors are arranged in a two-  !

out-of-two logic; therefore, both must trip to initiate the required action (closure  !

of the off-gas isolation valve to the main stack). This action, however, is  ;

automatically delayed by 15 minutes. A high radiation condition sensed by the l monitor in service would provide sufficient time to take corrective actions. Since a two-hour AOT is deemed acceptable for instrumentation in system such as the Reactor Protection System and Emergency Core Cooling Systems, it is appropriate to apply a two-hour AOT to these radiation monitors. Additionally, the NUREG-0123 AOT of one hour does not allow sufficient time to perform required surveillance testing without placing undue stress on the test performer.

The probability of a plant transient (e.g., loss of condenser vacuum) resulting from a trip of the coincident channel during surveillance testing is reduced since the channel under test will only be tripped for a small portion of the test interval.

This transient is bounded by existing analyses. Therefore, this proposed AOT will not significantly increase the probability or consequences of an accident previously evaluated.

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U.S. Nucl:cr R:gulatory Commission B16312\ Attachment 2\Page 3 Since no physical change is being made to the secondary containment, or to any systems or components that interface with the secondary containment, there is no change in the probability of any accident analyzed in the UFSAR.

The proposed change continues to ensure the secondary containment requirements meet the licensing basis. Also, the proposed changes are based on Standard Technical Specifications, NUREG-1433, " Standard Technical Specifications General Electric Plants, BWR/4," Revision 1 guidelines and implement actions to be taken when secondary containment integrity is not met.

If secondary containment integrity is not met, existing TS 3.7.C directs the plant to be placed in an operating condition where secondary containment is not required, e.g., COLD SHUTDOWN. A four hour allowable outage time is proposed which provides a period of time to correct the problem that is l commensurate with the importance of maintaining secondary containment during RUN, STARTUP/ HOT STANDBY or HOT SHUTDOWN. The secondary containment is not an initiator for any accident. Therefore, the proposed change will not increase the probability of any previously analyzed accident. This short time period ensures that the probability of an accident requiring secondary containment integrity operability occurring during periods when secondary containment integrity is inoperable is minimal. l l

The proposed surveillance requirement is based on the NUREG-1433 surveillance requiring periodic confirmation that at least one door in each of the double-doored accesses to the secondary containment is closed, provides additional assurance of secondary containment system integrity. While this is a ,

deviation from NUREG-1433 (which requires that both doors in each access be closed except for normal entry and exit), it is consistent with the current definition of Secondary Containment integrity, which requires that at least one door in each access opening be closed. Hence, the deviation is justifiable and represents increased passive testing which will provide increased awareness of plant conditions. Increased awareness of plant conditions should reduce the probability or consequences of any accident previously evaluated.

Since the aspects of secondary containment integrity affected by reactor building access control are being revised in this proposed amendment to agree with the allowable outage time allowed by NUREG-1433 upon loss of secondary containment integrity, the change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

Since the editorial items do not alter the meaning or intent of any requirements, they do not involve a significant increase in the probability or consequences of an accident previously evaluated.

U.S. Nucic r Regulatory Commission B16312\ Attachment 2\Page 4

2. The operation of Millstone Nuclear Power Station. Unit No.1. in accordance with the orooosed amendment. will not create the oossibility of a new or different kind of accident from any accident previously evaluated.

The proposed change to the protective instrumentation trip system specifications do not create the possibility of a new or different kind of accident because they do not introduce any new operational modes or physical modifications to the plant.

Instruments addressed in the proposed TS respond to changes in the plant.

The proposed AOTs provide a two-hour interval where the instrument is inoperable, yet the TS LCO action statement is not immediately entered.

Given a single failure, this could impact the response of the trip channel but not the initiation of the event. The only action resulting from the AOTs is to perform testing as required by TS. Spurious signals during testing could initiate transients but would be bounded by the previous transient analyres.

These tests do not subject the instruments to any conditions beyond their design specifications and are performed in accordance with approved testing standards. This testing ensures equipment operability by identifying degraded conditions, initiating corrective action and properly retesting them.

Therefore, the proposed TS changes will not introduce a new or different kind of accident than previously evaluated.

The two-hour instrumentation AOT for the Air Ejector Off-Gas System radiation monitors is slightly less restrictive than that allowed by the NUREG-0123. Since this requirement was relocated from NUREG-1433, there is no corresponding requirement for comparison. These radiation monitors are arranged in a two-out-of-two logic; therefore, both must trip to initiate the required action (closure of the off-gas isolation valve to the main stack). This action, however, is automatically delayed by 15 minutes. A high radiation condition sensed by the monitor in service would provide sufficient time to take corrective actions. Since a two-hour AOT is deemed acceptable for instrumentation in system such as the Reactor Protection System and Emergency Core Cooling Systems, it is appropriate to apply a two-hour AOT to these radiation monitors.

The proposed changes to Millstone Unit No.1 Technical Specifications Section 3.7/4.7 and associated bases were developed using the guidance provided in the Standard Technical Specifications, NUREG-1433, " Standard Technical Specifications General Electric Plants, BWR/4," Revision 1.

Augmentation of the existing surveillance requirements by incorporation of an additional NUREG-1433 based surveillance, provides additional assurance of secondary containment system integrity. While this is a deviation from NUREG-1433 (which requires that both doors in each access be closed except for normal entry and exit), it is consistent with the current definition of Secondary

U.S. Nuclear R gulatory Commission B16312\ Attachment 2\Page 5 1

Containment integrity which requires that at least one door in each access i j opening be closed. Hence, the deviation is justifisble and represents increased j

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passive testing which will provide increased awareness of plant conditions.

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increased awareness of plant conditions will not create the possibility of a new or different kind of accident from any accident previously evaluated. Since the proposed changes do not significantly degrade the present level of system

operability and add provisions from NUREG-1433, the proposed amendment
does not create the possibility of a new or different kind of accident from any j accident previously evaluated.

l l Since the editorial items do not alter plant configurations or operating modes, I j they do not create the possibility of a new or different kind of accident.

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3. The operation of Millstone Nuclear Power Station. Unit No.1. in accordance with 1 l the proposed amendment. will not involve a sianificant reduction in a maroin of  ;

j safety. '

i l The protective instrumentation surveillance requirements provide verification of l 3 the operability of the trip system instrumentation channels. In addition, the ,

l channel that monitors the identical Trip Function within the same trip system

! maintains trip capability for the relatively short duration that the coincidence l change is in effect. This ensures that protective instrumentation reliability is j maintained. The proposed change provides for a specific time period to perform required surveillances on instrument channels without trips present in l associated trip systems. This time allotment tends to enhance the margin of

safety by decreasing the probability of unnecessary challenges to safety f systems and inadvertent plant transients.

1 j The proposed TS provide a two-hour interval where the instrument is l inoperable, yet the TS LCO action statement is not immediately entered. If i a single failure occurred on the other channel of the trip system being tested j and the channel being tested was not in the tripped condition, a valid signal j might not provide the required protective action. The probability of an event j requiring initiation of the protective function within the proposed AOT is

! Iow. Additionally, surveillance testing is not generally performed on multiple sensors simultaneously. So, other trip functions and sensors remain

. operable and the probability of extensive inoperabilities affecting diverse trip

} functions is low.

i The existing TS definition for Instrument Functional Test would be difficult

to satisfy if the LCO condition of tripping the inoperable channel was i performed. A similar problem of complying with the Instrument Calibration

{ definition also exists. Moreover, the original TS bases submitted as part of i

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  • l U.S. Nuclear R:gulatory Commission i 1

B16312\ Attachment 2\Page 6 '

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the ~ application for Millstone Unit No.1's Provisional Operating License l l (dated October 7,1970) included recognition that instruments would be  !

j inoperable during required functional test and calibrations. Thus, these l l conditions were recognized in the original design bases and constitute part l 1 of the licensing bases of the plant. NUREG-012,3 providad specific time l frames and the AOTs addressed in the table notes and specific action l statements. Millstone Unit No.1 ACT values chosen are consistent with

these values and less than those approved in NUREG-1433 which had a i

! more detailed study performed to lengthen the AOT value. I The only action resulting from the proposed TS is to perform testing as I required by TS. Spurious signals during testing could initiate equipment or

{ plant transients but would be bounded by the previous transient analysis.

! These tests do not subject the instruments to any conditions beyond their

design specifications and are performed in accordance with approved testing l standards. This testing ensures equipment operability by identifying j degraded conditions, initiating corrective action and properly retesting them.

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

2 The two-hour instrumentation AOT for the Air Ejector Off-Gas System radiation j monitors is slightly less restrictive than that allowed by the NUREG-0123. Since

this requirement was relocated from NUREG-1433, there is no corresponding requirement for comparison. These radiation monitors are arranged in a two-

! out-of-two logic; therefore, both must trip to initiate the required action (closure

of the off-gas isolation valve to the main stack). This action, however, is

, automatically delayed by 15 minutes. A high radiation condition sensed by the 1 i monitor in service would provide sufficient time to take corrective actions. Since

! a two-hour AOT is deemed acceptable for instrumentation in system such as the Reactor Protection System and Emergency Core Cooling Systems, it is i

appropriate to apply a ttvo-hour AOT to these radiation monitors and does not j involve a significant reduction in the margin of safety.

I The addition of an allowable outage time of four hours for Sem cry q Containment Integrity has negligible effect on accident occurrence or consequences. Since the proposed change does not involve the addition or

modification of plant equipment, is consistent with the intent of the existing l Technical Specifications, is consis'ent with the current industry practices as

. outlined in NUREG-1433, (except for the deviation noted above), and is

! consistent with the design basis of the plant and the accident analysis, no action will occur that will involve a significant reduction in a margin of safety.

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Since the editorial items do not alter the meaning or intent of any requirements, they do not affect the margin of safety.

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i l Docket No. 50-245

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1 Attachment 3 1 ,

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Millstone Nuclear Power Station, Unit No.1 j Proposed Technical Specification Revision I j Allowable Outage Times l Marked-up Version of Current Technical Specifications and Bases k

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