ML20065P266

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Proposed Tech Specs Requesting Change to Auxiliary Feedwater Pump Operational Testing Frequency from Monthly to Quarterly Basis
ML20065P266
Person / Time
Site: Comanche Peak  Luminant icon.png
Issue date: 04/22/1994
From:
TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:
Shared Package
ML20065P242 List:
References
NUDOCS 9404290015
Download: ML20065P266 (13)
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ATTACHMENT 3 TO TXX-94116 AFFECTED TECHNICAL SPECIFICATION PAGES (NUREG.- 1468)

(Pages 3/4 7-3 and 3/4 7-4)

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PLANT S'YSTEMS '

AUXILIARY FEE 0 WATER SYSTEM LIMITING CONDITION FOR OPERATION 3.7.1.2 At least three independent steam generator auxiliary feedwater pumps and associated flow paths shall be OPERABLE with:

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a. Two motor-driven auxiliary feedwater pum powered from separate emergency busses, andps, each capable of being i

b.

One steam turbine-driven auxiliary feedwater pump capable of being powered from two OPERABLE steam supplies. <

l APPLICABILITY: MODES 1, 2, and 3. '

ACTION:

a.

With one auxiliary feedwater pump or associated flow path inoper- '

able, restore the required auxiliary feedwater pump or associated i flow path to OPERABLE status 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 following 6within hours.the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in HOT SHUTDOWN within the -

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With two auxiliary feedwater pumps or associated flow paths inoper-able, be in at least HOT STANDBY witin 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in 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 />.

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With three auxiliary feedwater pumps or associated flow paths inop-erable, immediately initiate corrective action to restore at least one auxiliary feedwater pump or associated flow path to OPERABLE status as soon as possible. 1

d. l With only one OPERABLE steam supply system capable of providing l power to the turbine-driven auxiliary feedwater pump, restore the required OPERABLE steam supplies within 7 days or be in at least HOT STANDBY following 6within hours.tha next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in HOT SHUTDOWN within the SURVEILLANCE REOUIREMENTS 4.7.1.2 Each auxiliary feedwater pump and associated flow path shall be demonstrated OPERABLE:

q7 b.'% At least once pe days on a STAGGERED TEST BASIS by:

1) Verifying that each motor-driven pump develops a differential pressure of greater than or equal to 1372 psid at a flow of greater than or equal to 430 gpm; COMANCHE PEAK - UNITS 1 AND 2 3/4 7-3

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PLANT SYSTEMS SURVEILLANCE REQUIREMENTS (Continued) 1

2) Verifying that the steam turbine-driven pump develops a differential-. pressure of greater than or equal to 1450 psid.at.

a test flow of greater than or equal to 860 gpa when the secondary steam supply pressure is greater than 532 psig. .The q provisions of Specification 4.0.4 are not applicable for entry A. At leg 3M

1) X[Viir17yhr .3r@-

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nat eacn'non-automatic valve in the flow path that (isnotlocked, sealed,orotherwisesecuredinpositionis'in its correct position; and 7.) ')61 ' Verifying that-each auxiliary feedwater flow control and.

isolation valve in' the flow path is in the fully open position whenever the Auxiliary Feedwater System is in standby for auxiliary feedwater automatic initiation or when above 10% RATED THERMAL POWER.  ?

C. X, At least once per 18 months during-shutdown by:' ,

1) Verifying that each automatic valve in the flow path actuates to its correct position upon receipt of an Auxiliary Feedwater ,.

Actuation test-signal, and  ; )

2) Verifying that each auxiliary feedwater pump start's as designed' automatically upon receipt of an Auxiliary Feedwater Actuation-test signal. The provisions of Specification'4.0.4 are not' applicable to the~ turbine driven auxiliary feedwater pump for entry into MODE 3.

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-l COMANCHE PEAK - UNITS 1 AND 2 3/4 7-4 1

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-t ENCLOSURE I TO TXX-94116 NUREG 1366. " Improvements to Technical Specification Surveillance Requirements," Enclosure 1 Section 9.1 Auxiliary Feedwater Pump and System Testing (PWR), Pages 49 and 50 '

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i 9 PLANT SYSTEMS 9.1 Auxiliary Feedwater Pump and study that used data from the time period early 1979 to I te 1982. NUREG/CR-4597 is a study done for the System TeStinE (PWR) NRC's Nuclear Plant Aging Research (NPAR) Program.

He Standard Technical Specifications and most plant Both studies concluded that a significant cause of failures Technical Specifications require the monthly testing of auxiliary feedwater (AFW) pumps. The Boiler and Pres- f AFW pumps is testing the pump by recirculating flow sure Vessel Code of the American Society of Mechanical through a minimum flow line which is not adequately Engineers (ASME Code),Section XI, Paragraph sized. Both studies deduced this from a review of licensee IWP-3400, requires the testing of Class 1,2, and 3 cen-event report (LER) data and other data on the types of failures that occurred.This was reinforced by expen,ence trifugal pumps "normally every three months." AFW pumps are the only pressurized water reactor (PWR) with feed pumps at fossil power plants; these are also pumps required by Technical Specifications to be tested horizontal multistage centrifugal pumps similar to AFW Pumps.

more frequently than required by the ASME Code.

Both reports recommend, among other things, that the The Technical Specifications do not require the testing to size of the recirculation lines be increased. In many cases, l be as thorough as required by the ASME Code. Table 9.1 this can be achieved by modifying the orifice in the recirc- I compares inservice testing required by the ASME Code ulation line although, as the flow increases through the I with that required by Technical Specifications. recirculation line, adequate flow to the steam generators must still be maintained. This could require a complicated Another difference in the testing is that, at some plants, interlock which would close valves on the recirculation  ;

one group may perform the monthly testing required by line when an actual demand signal is present.

the Technical Specifications, and a different group will perform the ASME Code testing every third month. Al' hough a change in recirculation flow from approxi-mate!y 10% to approximately 25% is the best solution to in both types of tests, the AFW pump takes suction from this problem, a reduction in the frequency of testing of the condensate storage tank and returns the water to the the AFW pumps from monthly to quarterly (the fre-condensate storage tank through a recirculation line. In quency specified in the ASME Code,Section XI), could most plants, the recirculation line is sized between 5% be a reasonable step to reducing the rate of wear, and 15% of the best estimate point flow (NP-4264, Vol.

1). This size was derived from considering temperature This problem should be put in perspective. Using the l rise in the pump. Pump manufacturers are now recom- EPRI data,236 LERs reporting failures of turbine-driven mending that standby pumps be tested at a flow no less AFW pumps were found over the period from early 1979 than 25% of the best efficiency point flow (NUREG/ through late 1982. Of these,163 (69%) reported failures ,

CR-4597). This is based on " hydraulic instability" of the related to the turbine (a figure which NP-4264 [Vol.1] j pump.nis is a term for unsteady flow phenomena which states is roughly consistent with previous EPRI studies on '

can cause degradation of the pump and which become the high. pressure coolant injection [HPCI] and reactor ,

more pronounced as the pump operates further away core isolation cooling [RCIC] systems in boiling water {

from its best efficiency point. reactors [BWRs]) and 73 (31%) were pump relate 1 Of l those that are pump related,23% were failures of the  !

Two studies have been done of the AFW system. Report " rotating element" as opposed to instrumentation and NP-4264 is an Electric Power Research Institute (EPRI) controls or valves.Thus, at the most,23% of the failures Table 9.1 Inservice testing required by Standard Technical Specifications and ASME Code ASME Code Standard Technical Specifications Inlet pressure -

Differential pressure -

Flow rate Flow rate Vibration amplitude -

Lubricant level and pressure -

Bearing temperature -

Discharge pressure 49 NUREG-1366

9 Plant Systems 1

l could be reduced by decreasing the surveillance fre- e AIV/EETV pump and valve surveillances have high 1 quency for the turbine-driven AIM pumps. risk impact per NUREG/CR-5200. l e The licensee burden is increased by monthly testing.

For the motor-driven AfM pump, the " rotating element" accounted for 13 of 50 (26%) reported failures (instru- e AFTV pump availability is increased by quarterly mentation and controls, as well as valves, were the other testing on a staggered basis.

major contnbutors to failure of the motor-driven AIM purnp). Thus, for the motor-driven AITV pump, at th most,26% of the failures could be reduced by less fre- Ru m W b quent surveillance or by decreasing the flow resistance of Change frequency of testing AITV pumps to quarterly on the recirculation line. a staggered test basis.

Another consideration is that, according to the NRC re- .

port NUREG/CR-4597,42% of the AITV pump failures 9.2 M a.in Steam L.ine Isolation Valve were found during surveillance testing and 29% were . (MSIV) Surveillance Testing found during operation (6% were found during mainte-nance and, for 23% the method of detection was not 9.2.1 Pressurized Water Reactors stated). 'thus, surveillance testing is important in detect-ing failures in the AIM system. Ilowever, surveillance The ASME Code,Section XI, Article IWV-3000 states testing also contributes to the problem.The availability of that " valves shall be exercised to the position required to the AITV pump, while related to the conduct of surveil- fulfill their function unless such operation is not practical lance testing, is not continuously linearly related to sur. during plant operation. If only limited operation is practi-veillance testing. That is, at some point an increase in c 1 during plant operation the valve shall be part-stroke surveillance testing (i.e., reducing the surveillance test exercised durmg plant operation and full-stroke exercised interval) mil not contribute to an increase in availability, during cold shutdown."

and in fact could contribute to equipment unavailability.

Analysts of AIM pump failures mdicates that a monthly Since closing a main steam line isolation valve (MSIV) surveillance test interval (STI) may be contributing t during operation would result in a plant trip, licensees do AIM pump unavailability through failures and equip- partial-stroke testing quarterly as specified by the ASME ment degradation. The changing of the AITV pump STI Code' to quarterly, on a staggered basis, is consistent with this The purpose of this test is to demonstrate that an MSIV is analysis. Conducting the tests on a staggered basis will capable of movement.

permit system testing monthly, while reducing ATM pump testing to quarterly, thereby maintaining a consis- 'Ihe test is being done in several different ways. The valve tent degree of reliability. The recommended change in

, may be closed rapidly in response to a close signal while testing frequency to quarterly is also consistent with the being tested. In this case, the valve closes until it is requirements of the ASME Code. stopped by a limit switch at 10% closed (or less, depend-ing on the distance that the valve disc can be placed into Findings the steam line without fully closing because of the force of a 'lhe ASME Code requires Class 2 pumps (such as AIM pumps) to be tested quarterly. Another method is to drain hydraulic fluid to reduce e system pressure which in turn tends to close the valve.

Technical Specifications re4utre testing suchPumps monthly. lhe operator must respond to the valve closure and se-cure the bleeding at the 10% closed level. If the operator e AfSV pump wear is caused by recirculating water vershoots this level or if the test equipment fails, the during tests through a line that has a smaller diame. MSIV will close and the plant will trip. Likewise, if the ter than presently recommended by pump manufac. limit switch fails, the valve will completely close, causing a turers, tnp.

e A review of LERs shows that, at most 23% of tur. The MSIVs were not designed to be tested by the latter bine-driven AIM pumps and 26% of the motor. testing methodJihe hydraulic fluid outlets were designed driven AFW pumps had failures due to the " rotating to be used for maintenance and not for periodic testing.

element" itself, as opposed to valves, controls, and so forth. A review of operating experience with MSIVs (from in-formation in NPE-4) shows many cases in which MSIVs e 42% of pump failures were found during surveil- could not be closed because of problems with the valves' lance testing. actuators or mechanical binding of the valves (as opposed NUREG-1366 50

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i-l' l ENCLOSURE 2 TO TXX-94116 i

j GL 93-05, "Line-Item Technical Specifications Improvements _to Reduce 1-' Surveillance Requirements for Testing During Power Operation,"

i Section 9.1, Auxiliary Feedwater Pump and. System Testing (PWR), Page 21 l

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Generic Letter 93-05 '

Enclosure 1 (TS 4.6.7.1, Cont.)

The ice condenser shall be determined OPERABLE:

a. -(No change.)
b. Once each refuelina interval by chemical analyses which verify that.

at least nine representative samples of stored ice have a boron con-centration of at least 1800 ppm as sodium tetraborate and a pH of 9.0:

to 9.5 at 20 degrees-C.

(Combined item b and b.1, with the surveillance interval being."Once each refueling interval" rather than "At least once per 9 months.")

n At least once per 9 months by: (Renumbered item b as item c.)

(No change to items c.1 and c.2. Renumbered items b.2 and b.3 as items c.1 and c.2.)

d 2 (No change to this item. Renumbered item c as item d) 9.1 Auxiliary Feedwater Pumo and System Testina (PWR)

Recommendation: Change frequency of testing AFW pumps to quarterly on a staggered test basis.

3/4.7 Plant Systems - Auxiliary Feedwater, [CE STS (Typ)] TS 4.7.1.2:

Each auxiliary feedwater pump shall be demonstrated OPERABLE:

a. At least once per 31 days by:
1. Verifying that each valve (manual, power-operated or automatic) in the flow path that is not locked, sealed, or otherwise secured in position, is in its correct position.

(Renumbered items a.1 and a.2 as items b.1 and b.2 below, and renumbered item a.3 as a.l.)

b. At least once oer 92 days on a STAGGERED TEST BASIS'by:
1. Verifying that each motor-driven pump develops a d.ischarge.

pressure of greater than or equal to psig at a flow of greater than or equal.to gpm.

2. Verifying that the turbine-driven pump' develops a discha'rge pressure of greater than or equal to psig at a' flow of-greater than or equal to gpm when the secondary' steam supply pressure is greater than psig. The provisions df Specification 4.0.4 are not applicable for entry int.o MODE 3.

(Added item b. Renumbered items a.1 and a.2 as items b.1 and b.2.)

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ENCLOSURE 3 TO TXX-94116 .J NUREG 1431. " Standard Technical Specifications, Westinghouse Plants.

TS 3.7.5 Auxiliary Feedwater (AFW) System" Pages 3.7-11 through 14 J

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AFW System 3.7.5 3.7 PLANT SYSTEMS 3.7.5 Auxiliary Feedwater (AFW) System LC0 3.7.5 [Three] AFW trains shall be OPERABLE.

NOTE-------------------------..

Only one AFW train, which includes a motor driven pump, is required to be OPERABLE in MODE 4.

APPLICABILITY: MODES 1, 2, and 3, MODE 4 when steam generator is relied upon for heat removal, l J

ACTIONS l CONDITION REQUIRED ACTION COMPLETION TIME A. One steam supply to A.1 Restore steam supply 7 days l turbine driven AFW to OPERABLE status, pump inoperable. AND 10 days from discovery of failure to meet the LCO B. Oce AFW train B.1 Restore AFW train to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> incoerable in MODE 1, OPERABLE status. - -

2 or 3 [for reasons AND other than Condition A] . 10 days from discovery of failure to meet the LC0 (continued)

WOG STS 3.7-11 Rev. O, 09/28/92

. AFW System 3.7.5 ACTIO'NS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME l

l C. Required Action and C.1 Be in MODE 3. 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> associated Completion --- ---

Time for Condition A AND C.2 Be in MODE 4. [18] hours QR Two AFW trains inoperable in MODE 2 or 3.

D. (Three) AFW trains D.1 ---------NOTE.----.--

inoperable in MODE 1, LC0 3.0.3 and all 2, or 3. other LCO Required Actions requiring MODE changes are suspended until one AFW train is restored to OPERABLE status.

Initiate action to Immediately restore one AFW train to OPERABLE status.

E. Required AFW train E.1 Initiate actiqn to Immediately inoperable in MODE 4. restore AFW train to OPERABLE status.

1 WOG STS 3.7-12 Rev. O,09/28/92

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AFW System

. 3.7.5 SURVEILLANCE REQUIREMENTS' 1

SURVEILLANCE FREQUENCY l

SR 3.7.5.1 Verify each AFW manual, power operated, and 31 days automatic valve in each water flow path,

[and in both steam supply flow paths to the steam turbine driven pump,] that is not locked, sealed, or otherwise secured in position, is in the correct position.

SR 3.7.5.2 -------------------NOTE------------------

Not required to be performed for the turbine driven AFW pump untfl [24 hours]

after a [1000] psig in the steam generator.

Verify the developed head of each AFW pump [31] days on a at the flow test point is greater than or STAGGERED' TEST equal to the required developed head. BASIS SR 3.7.5.3 Verify each AFW automatic valve actuates to [18] months the correct position on an actual or simulated actuation signal when in MODE 1, 2, or 3.

SR 3.7.5.4 -------------------NOTE.-----...-..- ---.

Not required to be performed for the turbine driven AFW pump until [24 hours]

after a [1000] psig in the steam generator.

Verify each AFW pump starts automatically [18] months on an actual or simulated actuation signal when in H00E 1, 2, or 3.

(continued)

WOG STS 3.7-13 Rev. O, 09/28/92 l

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AFW System 3.7.5 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.7.5.5 Verify proper alignment of the required Prior to AFW flow paths by verifying flow from the entering condensate storage tank to each steam MODE 2, generator. whenever unit l has been in i MODE 5 or 6 for > 30 days l

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l WOG STS 3.7-14 Rev. O, 09/28/92

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