ML20149H249

Application for Amend to License NPF-5,adding Footnote to Tech Spec Table 3.3.2-3,to Indicate That Instrument That Provides RWCU Sys Isolation High Sys Differential Flow Contains 45 Time Delay Function.Fee Paid

ML20149H249
Person / Time
Site:	Hatch
Issue date:	02/09/1988
From:	James O'Reilly GEORGIA POWER CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
Shared Package
ML20149H253	List: ML20149H249 ML20149H265
References
SL-4064C, TAC-66787, TAC-66788, NUDOCS 8802190188
Download: ML20149H249 (8)

Text

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Georg a Power Company 333 Pemont A.e%e Attaata. Georg a 3]303 Teie; tone 404 526 7651 Ma 1-ng A#ess Post Of' ce 80 4545 AUama Gec g a 30322 James P, o'Reilly h*' " " ' ' *

• sem v.ce r ess" twear cwawns SL-4064c 1921C X7GJ17-H600 February 9, 1988 U. S. Nuclear Regulatory Commission

! ATTN: Document Control Desk Hashington, D. C. 20555 PLANT HATCH - UNIT 2 NRC DOCKET 50-366 OPERATING LICENSE NPF-5 REQUEST TO REVISE TECHNICAL SPECIFICATIONS:

REACTOR HATER CLEANUP ISOLATION Off HIG4 OIFFERENTIAL FLOH Gentlemen:

In accordance with the provisions of 10 CFR 50.90, as required by 10 CFR 50.59(c)(1), Georgia Power Company hereby proposes a change to the Plant Hatch Unit 2 Technical Specifications Appendix A to Operating License NPF-5.

The proposed change would add a footnote to Table 3.3.2-3, Isolation Systo Instrumentation Response Time, to i.idicate that the instrumentation which provides reactor water cleanup system isolation on high system differential flow (Item 3.a. of the above Table) contains a 45 second time delay function.

Enclosure 1 provides a detailed description of the proposed change and the basis for the change.

Enclosure 2 details the basis for our determination that the proposed change does not involve a significant hazards consideration.

Enclosure 3 provides page change instructions for incorporating the proposed change into the Unit i Technical Specifications.

Yne proposed changed Technical Specifications Cnc*osure 3.

pages follow Payment of the filing fee in the amount of one hundred and fi f ty dollars is enclosed.

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6 U. S. Nuclear Regulatory Commission February 9, 1988 Page Two In order to allow time for procedure revision and orderly incorporation into copies of the Technical Specifications, we request that the proposed amendments, once approved by the NRC, be issued with an effective date to be no later than 60 days from the issuance of the amendment.

Pursuant to the requirements of 10 CFR 50.91, a copy of this letter and all applicable enclosures will be sent to Mr. J. L. Ledbetter of the Environmental Protection Division of the Georgia Department of Natural Resources.

Mr. James P. O'Reilly states that he is Senior Vice President of Georgia Power Company and is authorized to execute this oath on behalf of Georgic Power Company, and that to the best of his knowledge and belief, the facts set forth in this letter and enclosures are true.

GEORGIA POWER COMPANY By: __

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,s P. 0'Reill Sworn to and subscribed before me ththhy of February 19'8b d L /Notaryt'/A

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Enclosures:

1. Basis for Proposed Change

2. Significant Hazards Consideration

3. Change Instructions

4. Filing Fee - $150.00 c: (see next page) 1921C

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ENCLOSURE 1 PLANT HATCH - UNIT 2 l NRC DOCKET 50-366 OPERATING LICENSE NPF-5 REQUEST TO REVISE TECHNICAL SPECIFICATIONS:

REACTOR HATER CLEANUP ISOLATION ON HIGH DIFFERENTIAL FLOH BASIS FOR CHANGE REOUEST Georgia Power Company has been requested by NRC to provide clarifying changes to the Plant Hatch Unit 2 Technical Specifications (TS) in order to indicate the presence of a timer in the logic Tor instrumentation which isolates the reactor water cleanup (RHCU) system due to high differential flow conditions. The change hereby proposed will result in a description identical to that provided in NRC approved BHR Standard Technical Specifications (NUREG 0123 Revision 3) for this common BWR ,

design feature. This change is clarifying in nature and does not represent a change to the design or operation of the plant as described in the FSAR. NRC Region II, by letter of December 29, 1987, granted enforcement discretion to GPC with regard to this matter, for that time period necessary for processing and approval of this TS change.

Plant Hatch Unit 2 Technical Specifications (TS) Table 3.3.2-3 provides instrumentation response time requirements for isolation actuation instrumentation. The isolation actuation instrumentation response time, as provided by Note (') to this Table, is a subset of the ISOLATION

• SYSTEM RESPONSE TIME, and is that time interval from when the monitored '

parameter exceeds its isolation actuation setpoint at the channel sensor until the isolation valve actuator receives a signal to close.

Item 3.a of the above Table addresses instrumentation which isolates the RWCU system on high system differential flow, and provides an instrumentation response time requirement of less than or equal to 13 for this function.

seconds However, the circuit for the high '

differential flow isolation signal contains a timer such that the high differential flow signal must be present for 45 seconds before a valve isolation signal is generated. In light of the above definition, and without the explanatory note normally found in BWR STS, the presence of the timer has been interpreted by NRC as conflicting with the 13 second instrumentation response time requirement provided by Table 3.3.2-3. ,

GPC proposes to incorporate an explanatory footnote to Table 3.3.2-3,  !

indicating the presence of the timer and the duration of the time delay.

As noted, this footnote is identical to that provided in BWR STS for this .;

common BWR design feature.

t 1921C El-l 2/9/88 SL-4064c i

5 ENCLOSURE 1 (Continued)

REQUEST TO REVISE TECHNICAL SPECIFICATIONS:

REACTOR HATER CLEANUP ISOLATION ON HIGH DIFFERENTIAL FLOW BASIS FOR CHANGE REOUEST The time delay for this particular isolation function is required to prevent RHCU isolations due to spurious signals that may be generated  ;

during reactor startup and shutdown, instrument testing, pump start, or '

demineralizer changeout. Adverse effects of these spurious RHCU isolations include . reactor coolant conductivity excursions and unnecessary challenges to the isolation system.

The time delay feature has been present since Plant Hatch Unit 2 was built and was previously analyzed and found to have no unacceptable safety impact. The accident analysis does not assume functioning of the RHCU high differential flow isolation system. Containment isolation for accident analysis RHCU pipe breaks is provided by one of the following Class lE circuits meeting all applicable criteria for redundancy, separation, etc.: Reactor Vessel Hater Level Low Low, RHCU Area Temperature High, or RHCU Area Ventilation Differential Temperature  ;

High. The RWCU high differential flow isolation is a single channel system provided for leak before break protection. General Electric's letter to GPC of December 16, 1987, states that "...Because the set point is for leak before break and is, therefore, a precursor to line break protection given by reactor water level signals, the time delay before the set point is not part of that accident analysis. Rather, it serves as a system operation buffer to prevent operation transients when no real leak exists, but a trip signal does. The time delay reflects a conservative measure of how fast a line crack may propagate to a total cross section break after the technical specification value for the leak rate is exceeded...".

As has been our past practice, GPC will continue to consider the 13 second maximum instrumentation response time to be exclusive of the time delay, and will bypass the time delay relay for performance of the response time test. He will additionally test the time delay function to l ensure that the time delay does not exceed 45 seconds. I l

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1921C El-2 2/9/88 l SL-4064c l l

ENCLOSURE 2 PLANT HATCH - UNIT 2 NRC DOCKET 50-366 OPERATING LICENSE NPF-5 REQUEST TO REVISE TECHNICAL SPECIFICATIONS:

REACTOR HATER CLEANUP ISOLATION ON HIGH OIFFERENTIAL FLOW 10 CFR 50.92 EVALUATION Pursuant to the requirements of 10 CFR 50.92, Georgia Power Company has evaluated the proposed amendment for Plant Hatch Unit 2 and has determined that its adoption would not involve a significant hazards consideration. The basis for this determination is as follows:

Procosed Change:

Georgia Power Company has been requested by NRC to provide clarifying changes to the Plant Hatch Unit 2 Technical Specifications (TS) in order to indicate the presence of a timer in the logic for instrumentation which isolates the reactor water cleanup (RHCU) system due to high differential flow conditions. It is proposed to add a footnote to Table 3.3.2-3, relative to Item 3.a. denoting the existence of the timer and the duration of the time delay.

B1111:

The change hereby proposed will result in a description identical to that provided in NRC approved BHR Standard Technical Specifications (NUREG 0123 Revision 3) for this common BWR design feature. This change is clarifying in nature and does not represent a change to the design or operation of the plant as described in the FSAR.

The proposed change does not involve a significant increase in the probability or consequences of an accident because no changes to plant operation or design are involved. This change clarifies a design feature of a plant leak detection system for which no credit is taken in the accident analysis. Containment isolation for accident analysis RHCU pipe breaks is provided by one of the following Class 1E circuits meeting all applicable criteria for redundancy, separation, etc.: Reactor Vessel Water Level Low Low, RHCU Area Temperature High, or RHCU Area Ventilation Differential Temperature High. The RHCU high differential flow isolation is a single channel system provided for leak before break protection.

The 45 second time delay is commensurate with this function and is a standard BWR design feature.

The possibility of a different kind of accident from those analyzed previously is not created by this change, since the design function of systems, as described in the FSAR, is not affected.

1921C E2-1 2/9/88 SL-4064c

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ENCLOSURE 2 (Continued)

REQUEST TO REVISE-TECNNICAL SPECIFICATIONS:

REACTOR HATER CLEANUP ISOLATION ON HIGH DIFFERENTIAL FLOH '

10 CFR 50.92 EVALUATION Margins of safety are not significantly reduced by_ this change. No ,

change to plant design or operation is involved. This change -is '

4 clarifying in nature and has no impact on margins of safety.

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1921C E2-2 2/9/88 SL-4064c

t ENCLOSURE 3 PLANT HATCH - UNIT 2 3 NRC DOCKET 50-366' .

OPERATING LICENSE NPF-5 REQUEST TO REVISE TECHNICAL SPECIFICATIONS * '

REACTOR HATER CLEANUP ISOLATION ON HIGH DIFFERENTIAL-FLOW PAGE CHANGE INSTRUCTIONS

' The proposed changes to the Technical Specifications (Appendix A to Operating License NPF-5) would be incorporated as follows:

Remove' Pace Insert Page 3/4 3-19 3/4 3-19 3/4 3-20 3/4 3-20 .

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