ML20112F117

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Safety Evaluation Re Analog Transmitter Trip Sys
ML20112F117
Person / Time
Site: FitzPatrick Constellation icon.png
Issue date: 03/21/1985
From:
POWER AUTHORITY OF THE STATE OF NEW YORK (NEW YORK
To:
Shared Package
ML20112F106 List:
References
NUDOCS 8503270403
Download: ML20112F117 (10)


Text

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ATTACHMENT II to JPN-85-22 SAFETY EVALUATION RELATED TO ANALOG TRANSMITTER TRIP SYSTEM (ATTS)

(JPTS-85-OO4)

NEW YORK POWER AUTHORITY JAMES A. FITZPATRICK NUCLEAR POWER PLANT DOCKET NO. 50-333 l DPR-59 I

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I. Description of the Chances The proposed changes to the James A. FitzPatrick Technical Specifications are the result of plant modifications to implement the use of the ATTS system.

Section 3.1 (Bases) on page 33, the words "(Pressure ~-

Switches)" are deleted from the first full paragraph. '

Section 4.1 (Bases) on page 38, the words "non-ATTS (Analog

! Transmitter Trip System)" was added to the second sentence of I the second paragraph. The words "non-ATTS" are added to the third sentence. In addition, the remainder of the paragraph was revised to read as follows:

"The ATTS analog devices (sensors),

bi-stable devices (master and slave trip units) and power supplies have been

, evaluated for reliability by Mean Time Between Failure analysis or state-of-the-art qualification type testing meeting the requirements of IEEE 323-1974. Considering the 2-hour monitoring interval for analog devices as assumed above, the instrument checks and functional tests as well as the analyses and/or qualification type testing of the devices, the design reliability goal for system reliability of 0.9999 will be attained with ample margin."

, Section 4.2 (bases) on page 61, the second and third sentences of the first paragraph are replaced with the following:

"The same design reliability goal as the Reactor Protection System is generally applied. Sensors, trip

, devices and power supplies are tested, calibrated and checked at the same frequency as comparable devices in the Reactor Protection System."

The following are changes made to Table 4.1-1 (" Reactor Protection System (SCRAM) Instrument Functional Test Minimum Functional Test Frequencies for Safety Instrument and Control Circuits") on pages 44, 45 and 45a:

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On page 44. Instrument Channels "High Drywell Pressure" and " Reactor Low Water Level" Groups are changed from "A" i to "B". Notes "(4) & (8)" are added for Functional Test and Minimum Frequency, respectively. For "High Water Level in Scram Discharge Instrument Volume" (Group B only), note "(4)" is added to Functional Test and notes

"(1)" and "(8)" are added to Minimum Frequency.

On page 45. Instrument Channel " Turbine First Stage Pressure Permissive" Group is changed from "A" to "B".

Functional Test note "(4)" is added and Minimum Frequency l a

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i Io Description of Chances (cont'd)

-- of "Every 3 months" -is changed to "once/ month". _. -

i . " Instrument check of once/ day" is now denoted as note

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"(8)". --

90n page 45a; note "(8)", stating " Instrument -check once -

i per day", is added .

! The.following changes are made to Table 4.1-2 (" Reactor l Protection System (SCRAM) Instrument Calibration Minimum

, Calibration Frequencies for Reactor Protection Instrument Channels") on pages 46 and 47.

On Page 46 Instrument Channels "High Drywell Pressure,"

) " Reactor Low Water Level," and " Turbine First Stage

!- Pressure Permissive" Groups are changed from "A" to "B".

The calibration frequencies for the first two channels are

! changed from "Every 3 months" to " Note (7)", and for the i third channel from "Every 6 months" to " Note (7)". In i addition, the calibration frequency for "High Reactor i Pressure" is changed from "once/ operating cycle to " Note l (7)".

1 On page 47 Note 7, stating " Sensor calibraticn once per

, operating cycle. Master / slave trip unit calibration once

, per 6 months", is added.

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\ The following changes are made to Table 4.2-1 (" Minimum Test l and Calibration Frequency for PCIS") on page 78:

Instrument Channel items 2, 4 and 5 Calibration Frequencies are changed from "Once/3 months" ts "(15)".

Instrument channel items 3 and 7 calibration frequencies are changed from "once per operating cycle" to "(15)".

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Instrument Channel heading note "(5)" is changed to "(8)".

Note "(4)" is added to Instrument Check heading.

Instrument Check Frequencies for instrument channel items t

4, 5 and 7 are changed from "None" to "Once/ day".

1 Note "(5)" is added to the instrument functional test column for instrument channel items 2, 3, 4, 5 and 7.

Notes "(7) and (9)" replaces notes "(4) and (6)" for logic system functional test, respectively.

t The following are changes made to Table 4.2-2 (" Minimum Test

and Calibration Frequency for core and containment Cooling Systems") on pages 79 and 80.

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Note "(4)" is added to instrument check column heading.

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Item No. "

2 Drywell Pressure" is revised to read "2a)

} Drywell Pressure (Non-ATTS)."

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I ., Description of Chances (cont'd)

-~ - . Add new iten, "2b) Drywell Pressure (ATTS)" with corresponding instrument functional test of "(1)",'~' ~27 calibration frequency of "(15)", and instrument chect "once/ day".

Item No. "3) Reactor Pressure" is revised to read'"3a)

Reactor Pressure (non-ATTS)."

- Added new item, "3b) Reactor Pressure (ATTS)" with instrument function test of "(1) & (5)", calibration frequency of "(15)", and instrument check "once/ day".

Instrument check for channel items 2b, 3b, 9 and 12 are changed from "None" to "Once/ day".

  • Calibration frequency for channel items 1, 9, 10 & 12 are changed from "Once/3 months" to "(15)".

- Instrument channel items 4, 6 and 17; changed "NA" to "NONE".

Note "(5)" is added to instrument functional test column for channel items 1, 2b, 3b, 9, 10 and 12.

On page 80, notes "(4) & (6)" are revised to read "(7) &

(9)" throughout.

I i The following are changes made to Table 4.2-3 (Minimum Test

, and Calibration Frequency For Control Rod Blocks Actuation")

) on page 81.

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Note "(3)" under Instrument Functional Test column is

{ replaced with note "(5)", and indicated only once at the j heading.

l Instrument check heading Note "(9)" is replaced with Notes -

"(12) & (4)".

l - Calibration frequencies for instrument channel items 3, 4 I

7, 8 and 9 are changed from Note "(2)" to Notes "(3) &

(6)".

Instrument check frequencies for instrument channel items 3, 4 & 7 are changed from note "(2)" to "once/ day".

The word "None" is added to Instrument check column for instrument channel items 8 & 9.

Instrument channel item No. 10 (" Scram Discharge Instrument Volume - High Nater Level") will be clarified

, to indicate " Group B Instruments". In addition, under

! instrument functional test note "(2)" is changed to note i "(1)"; calibration frequency of "once/ operating" is

! changed to "once/3 months"; and instrument check frequency j of "N/A" is changed to "once/ day".

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I. Description of Chances (cont'd)

, The following are changes made to Table 4.2-4 (" Minimum Test And Calibration Frequency For Radiation Monitoring Systems")

on page 82.

Instrument check heading notes "(2) & (9)" are replaced with notes "(4) & (12)", respectively.

Logic system functional test heading notes "(4) & (6)" are replaced with notes "(7) & (9)", respectively.

On Table 4.2-5 (" Minimum Test And Calibration Frequency for Drywell Leak Detection") page 83, instrument check heading note "(4)" is added.

The following are changes to Table 4.2-6 (" Minimum Test And Calibration Frequency for Surveillance Instrumentation") on page 84:

i Calibration Frequency for Instrument Channel item No. 7

changed from "N/A" to "None".

Note "10" is changed to read Note "13" for Instrument Channel item No. 9.

Note "11" is changed to read Note "14" for Instrument Channel items No. 11 & 12.

Note "(4)" is added to Instrument Check heading.

The following are changes to " Notes For Tables 4.2-1 through 4.2-6" on page 85:

4 Notes 2 & 3 are changed and renumbered to read the

! following:

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2. Functional tests are not required when these instruments are not required to be operable or are tripped. Functional tests shall be performed within
seven (7) days prior to each startup, i
3. Calibrations are not required when these instruments are not required to be operable or are tripped.

i Calibration tests shall be perform within seven (7) days prior to each startup or prior to a preplanned shutdown.

! 4. Instrument checks are not required when these l instruments are not required to be operable or are tripped.

5. This instrumentation is excepted from the functional

! test definition. The functional test will consist of l

injecting a simulated electrical signal into the measurement channel.

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l 1 Description of Changes (cont'd)

6. These instrument channels will be calibrated-using

, simulated electrical signals once every three months.

i - Notes 4, 5, 6, 7, 8, 9, 10 and 11 are renumbered to read 7, 8, 9, 10, 11, 12, 13 and 14, respectively.__ _

Note 15 is added to read the following:

' 15. Sensor calibration once per operating cycle. Master /

slave trip unit calibration once per 6 months.

j II. PurDose of the Changes The FitzPatrick plant currently uses mechanically operated sensors and relays in the design logic for the Reactor Protection System and in the automatic initiation logic for the Emergency Core Cooling System. Operating experience has shown that due to age and wear, mechanical sensors inherently drift out of tolerance and require frequent maintenance, testing, calibration and repair. During these checks, personnel errors as well as physical jarring of the sensors have caused unscheduled plant shutdowns. Replacement of mechanical sensors and relays with an Analog Transmitter Trips System (ATTS) is a technically superior approach to meet safety system trip input requirements.

The ATTS is an all solid-state electronic trip system designed .

to provide stable and accurate monitoring of protection '

2 parameters. -Installation of the ATTS will result in the following:

Plant safety will be improved because an electronic system

is more reliable than a mechanical system.

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The number of plant outages due to inadvertent reactor shutdown will be reduced with the use of more reliable instrumentation.

There will be a significant decrease in time required for surveillance testing of the instrumentation.

Maintenance and associated radiation exposure will be reduced.

Equipment failure due to instrument drift and required Licensee Event Reports to the NRC will be reduced.

Plant modifications for the installation of the ATTS system will be completed during the current reload sir (6) refueling outage scheduled for February of 1985. The modifications j consist of replacing existing direct and differential pressure i activated mechanical sensor switches with an analog system

{ capable of more accurately monitoring certain ECCS and RPS protection parameters. In addition, temperature elements 1

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II.

  • Purpose of the Chances (cont'd) associated with leak detection systems located in the steam

, tunnel, personal access, torus, RHR heat exchanger, and crescent areas will be replaced with nuclear qualified Class 1E Resistance Temperature Detectors (RTD). Each RTD used in this modification has been environmentally and seismically qualified based upon the conditions at the FitzPatrick Plant.

The qualification for these instruments is based upon IEEE 323-1974 and IEEE 344-1975 and is more stringent than the instruments being replaced. System components such as switches, racks, and accessories will also be replaced with

-equipment meeting more stringent codes and standards.

As a result of these plant modifications, the proposed changes to the FitzPatrick Technical Specifications are necessary to implement the use of the ATTS.

The proposed changes on pages 44, 45, 45a, 46, 47, 78, & 79 are intended to incorporate the new minimum tests and calibration frequencies as a result of the ATTS modification.

The proposed changes to " Notes For Tables 4.2-1 through 4.2-6" (Notes 2 & 3) on page 85 are intended to clarify statements concerning functional tests, calibration tests, and functional test exemption. This is also in accordance with the standard Technical Specifications. These notes have been broken up to read 2, 3, 4, 5 & 6. The remainder of the notes on this page are renumbered, and Note 15 is added to describe calibration frequency of different components of the ATTS.

The renumbering of notes on pages 78 through 84 are editorial in nature.

The proposed changes to instrument channel items Nos. 4, 6&

17 on page 79 are for consistency and therefore editorial in

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nature.

The proposed changes to instrument channel item No. 10 on Table 4.2-3 (Page 81) are now in agreement with Table 4.1-2 (page 46).

The proposed changes to the Bases, pages 33, 38 & 61, are intended to clarify the use of "Non-ATTS & ATTS" analog devices.

III. Impact of the Chances The ATTS modification at the FitzPatrick Plant and its associated Technical Specification changes will reduce the number of challenges to the Reactor Protection System. This modification is being installed to improve plant availability, simplify calibration procedures, and enhance plant safety J

III. Impact of the Chances (cont'd)

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Changing to an' analog' system will improve overall sensor accuracy and reliability; reduce the time the RPS logic will be in a half scram condition and therefore reduce the potential for inadvertent plant scrams; reduce the functional test calibration frequency; reduce the number of Licensee ~

Event Reports filed with the NRC for setpoint drift;.and

, reduce radiation exposure to plant personnel.

The replacement of mechanical sensor switches with an analog transmitter trip system will more accurately and reliably

monitor ECCS and RPS protection parameters. As such, each parameter sensed by the analog system do not alter the requirements for instrument initiation, function, and operation that existed prior to the modification. Therefore, implementation of the ATTS only affects the system at the

! sensor level, not the logic level.

The proposed changes, regarding the reduction of surveillance requirements, are specified to maintain availability, accuracy, and reliability at the level which existed prior to the modification. The existing system (mechanical sensors) required a high rate of surveillance testing which required i the plant be placed in a half-scram condition for significant I amounts of time. The new ATTS sensors require less

) maintenance, surveillance testing, and nearly eliminate

! instrumentation setpoint drifts. The reason for this is that

electronic components are highly reliable, more accurate, and have low failure rates. Therefore they required less surveillance testing and maintenance to insure the same level

! of safety. This conclusion is supported in Section 3.4 of General Electric (GE) Topical report NEDO-21617-A. This GE report describes ATTS availability (as defined by 1

IEEE-344-1975) in detail.

l The operation, design and surveillance criteria, upon which the ATTS modification is based, has been analyzed by General Electric Licensing Topical Report NEDO-21617-A Class I December 1978, " Analog Transmitter Trip Unit System for Engineered Safeguard Sensor Trip Inputs." This report documents the improvements in performance that the ATTS l provides over the existing mechanical switches. The report j was noted in NRC letter dated June 27, 1978, as acceptable for reference in license applications. In addition, 3

state-of-the-art qualification type testing has been conducted in accordance with IEEE 323-1974 (Reference d). This testing

. demonstrated qualified life longer than those "Mean Time i

Between Failures" discussed in NEDO-21617-A (Reference c).

The proposed changes to the Technical Specifications will not alter the conclusions reached in the FSAR and SER accident analyses.

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III. Impact of the Chances (cont'd) i
c The Authority considers that this proposed _ amendment to the

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i Fitzpatrick Technical Specifications can be classified as not i likely to involve a significant hazards consideration since '

i this proposed amendment, as per 10 CFR 50.92, does not:

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(1) involve a significant increase in the probability or

consequences of an accident previously evaluated 4

because the proposed changes, as described above, only improve sensor accuracy. In addition the reduction in surveillance requirements do not reduce system 4

accuracy or availability as described above-and in NEDO-21617-A. Therefore, all functions of the system i L will remain the same.

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,  ; (2) create the possibility of a new or different kind of

, L accident from any accident previously evaluated, since

! . the incorporation of the ATTS system with the reduced j  : surveillance requirements will only improve sensor j accuracy and reliability and not affect system logic functions, as described above.

l l (3) involve a significant reduction in a margin of safety, j since the replacement of existing mechanical sensor switches with an analog system (ATTS) will more accurately monitor ECCS and RPS protection parameters, thereby, increasing the margin of safety for sensor

f reliability. Additionally, reducing the surveillance i ; requirements will not involve a significant reduction i . in a margin of safety, since the reduction is based on
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system accuracy and availability as described above and in NEDO-21617-A.

IV. Implementation of the Chances

_The changes proposed will not impact the fire protection program at FitzPatrick, nor will the changes impact the i environment. Long-term radiation exposure of personnel is expected to decrease as a result of the longer interval for f'

calibration and testing.

V. Conclusion

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The incorporation of these changes:

a) will not change the probability or the consequences of an accident or malfunction of equipment important to safety j as previously evaluated in the Safety Analysis Report:

i i b) will not increase the possibility or an accident or i

malfunction of a different type than any evaluated l previously in the Safety Analysis Report; l

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.. V . E9.gplusion (cont'd) c)

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, will not reduce the margin of safety as defined in the

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basis for any Technical Specifications d) does not constitute an unreviewed Safety as defined in 10 CFR 50.59; and _ _ _ _ _ . . _

e) involves no significant hazard considerations, as defined in 10 CFR 50.92.

VI. References

a. James A. FitzPatrick Nuclear Power Plant Final Safety Analysis Report (FSAR), Rev. 2 July, 1984, Sections 7.2, 7.3, and 14.5.
b. James A. FitzPatrick Nuclear Power Plant Safety Evaluation Report (SER).
c. General Electric Licensing Topical Report NEDO-21617-A Class I, Dated December 1978, " Analog Transmitter / Trip Unit System For Engineered Safeguard Sensor Trip Inputs."
d. IEEE 323-1974 - Qualifying Class lE Equipment for Nuclear Power Generation Stations.
e. IEEE 344-1975 - Recommended Practices for Seismic Qualification of Class 1E Equipment for Nuclear Equipment.
f. Reg. Guide 1.89 - (IEEE 323-1974) - Qualification of Class 1E Equipment for Nuclear Power Plants.
g. James A. FitzPatrick Nuclear Power Plant Technical Specification.
h. NRC. letter. O. D. Parr to G. G. Sherwood (G.E.), dated June 27, 1978 (MFN-279-78),' Review of General Electric -

Topical Report NEDO-21617, " Analog Transmitter / Trip Unit System for Engineered Safeguard Sensor Trip Input",

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