ML051050147

E-mail from P. Krohn, Riii, to H. Chernoff, NRR, Tdafwp Calc

ML051050147
Person / Time
Site:	Point Beach
Issue date:	06/30/2004
From:	Paul Krohn NRC/RGN-III
To:	Jamnes Cameron, Chernoff H Office of Nuclear Reactor Regulation
References
FOIA/PA-2004-0282
Download: ML051050147 (6)

Text

Harold Chernoff - TDAFWP Cabc. FYI Page 11 r1 From: NPGK1 @NRC.GOV" <pgkl @nrc.gov> 1 r. By To: P'4 HKC@NRC.GOV"<hkc@nrc.gov>, JLC@NRC.GOV" <jlc@nrc.gov>

Date: Wed, Jun 30, 2004 10:35 AM

Subject:

TDAFWP CaIc. FYI CC: "PLL@NRC.GOV" <pll~nrc.gov> I LAI-3 2

rr/e Af' >I .ar Point Beach Nuclear Plant CALCULATION COVER SHEET dv z 4 {/Yt hoo .C Calculation/Addendum Number: Title of Calculation/Addendum: V e- E f, , /I ,

2001-0056 -TDAFP Mini Recirc Vaive (6/2AF-4002) Instrument Air Accumulator Sizing I 9.

System (CHAMPS Identifier Codes):

IA - Instrument Air, AF -. Auxiliary Feedwater O Original Calculation/Addendum ] Supersedes Calcuilation/Addendum 03 RevisedCilciilatiolAddeiidumRevisi6fn# 2 Associated Documents: MR 02-001, SCR 2002-0010,IT 8C. IT 9C QA Scope 0 Yes El No _

Discipline O CIV 0 NUC 0 ELEC n COMP O I&c El CHEM/RAD Superseded By ZMECH a SYST Calculation/Addendum#

This Calculation has been reviewed in accordance with NP 7.2.4. The review was Reviewers' Initials accomplished by one or a combination of the followingj(check all that apply): ReneuersImals El A review of a representative sample of repetitive calculations.

o A review of the calculation against a similar calculation previously performed.

>3 A detailed review of the original calculation.

E A review by an alternate, simplified, or approximate method of calculation.

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CALC 2001-0056 Rev 02 RCC 10/24/2003 Page 4 of 13 1.0 PURPOSE The purpose of this calculation is to determine ithe required volume of new instrument air accumulator tanks (1/2T-212) that were'installed by MR 02-001 on the supply to the I/2AF4002 Turbine Driven Auxiliary Fecdwater Pump (TDAFP) Tminimum recirculation control valves.- These accumulators are-required because ihe AF-4002 valves .have a safety-related function to oppen to prevent the TDAFPs (1/2P?-29) from being operated at low flow foilowing operator action to control steam generator level. The normal instrument air supply cannot be credited 'to support the safety function to open these valves during some accidents.

The valves are required to open if the TDAFP discharge flow is throttled back to control steam generator levels following a Loss of All AC power (LOAC), Loss of Normal Feedwater (LONF), Station Blackout'(SBO), Steam Generator Tube Rupture (SGTR), Main Steam Line Break (MSLB), Appendix R fire scenario, Anticipated Transient without Scram (ATWS), Design Basis Earthquake, or loss of instrument air. The AF-4002 valves will get an open

'signal when the TDAFP flow drops to 110 gpm. In several of the above scenarios, instrument air will not be available, and the valves will not open. LER 266/2001-,005-00 identified that this 'was -a potential common mode failure for the auxiliary fecdwaterpumps, and that it resulted in an increased calculated core damage frequency (CDF). Therefore, a backup air source will be installed to reduce CDF and to support the new safety-related function of the AOVs.

'MR 02-001 installed accumulator tanks in the instrument 'air supply line to the AF-4002 valves. Dual check valves upstream of the accumulator will isolate the tanks from'the rest of the instrument air system when pressure is lost.

and the trapped volume of air in the accumulator will provide the necessary air to stroke the valve the required number of times. The 'nminimum required :volume of these new tanks rWill be determnied,-as will the acceptance' criteria for leakage testing of the check valves; tubing,'and recirculation valve actuator. - 5 Revision 2 of this calculation is being done because the current acceptance criteria for'drop testing in IT BC and IT 9C doino~tade4iately bound the leakage assumption in'this'calculation (see CA052144). The allowable leakage will be increased, and a range of test acceptance, criteria will be calculated. Operability limits on leakage will be calculated to show that there is additional margin in the system design to accommodate increased leakage.

Additionally, several other minor enhancements will be made based on suggestions from the AFW assessment 'team review. Note that' t'the time of this revision, MR 02-001-has already been installed, and the tank 'size is already fixed.

2.0 METHODOLOGY AND ACCEPTANCE CRITERIA The required volume 'of the accumulators will be calculated using simple ideal gas equations. The minimum pressure needed to stroke the valves is known, and 'the tank will be sized such that this minimum pressure is still available after the required time and number of strokes specified. The AF4002 valves are controlled either full open or full closed. The AF-4002-S solenoid valves open to pressurize'the operator and stroke the valve open,'then close and vent the entire volume of air fromthe operator to stroke the-valve closed (Ref 4.1). The accumulator tank must contain sufficient air to fill this volume of tubing and the actuator each time'the valve is to be'strbked. The necessary air volume required to stroke the valve each time and the estimated volume of 'air leakage will be calculated and used to determine the necessary air yolume in standard cubic feet, which will correspond to a certain tank volume.

The leakage rate assumed for tank sizing will be converted into a pressure drop for a specified time duration. This will provide a basis for acceptance criteria for leakage testing that is performed periodically per IT 8C and IT 9C. A range of allowable leakages and pressure'drops 'will'be calculated to provide input 'into the procedures. The procedures will require that testing be done at 'the maximum accumulator pressure to ensure that the measured leakage bounds operation over the entire range of pressures. The acceptance criteria will be chosen to be less than the maximum allowable to provide some margin for increased leakage in the future.

The previous revisions of this calculation showed that there was additional margin present since the recirculation AOV did not need to be fully open to provide adequate recirculation flow. This however only provided a limited

CALC 2001-0056 Rcv 02 RCC 102412003 Page 5 of 13 amount of additional margin for operability and added 'complexity to the calculation, and thus has been removed with revision 2. The operability limits will be calculated using the actual tank size assuming a more realistic number of valve strokes in a two hour period and using the actual vblumes of tubing pressurized during leak testing. This will provide the basis for any future operability recommendation if leakage has increased.

There were no acceptance criteria for the previousIrevisions of calculation. However, since 150 gallon accumulator tanks have now been installed per MR 02-001 (Ref 4A),'the required tank volume calculated in this revision must be less than this value.

3.0 ASSUMPTIONS Validated 3.1. The AFW pump room will assumed to be at a constant 90 'F prior to and following loss of instrument air.

Basis: T'he room temperature will affect the quantity of gas in the accumulator prior to instrument air loss and isolation %ofthe check valves. Based on the ideal gas law, a higher temperature at a constant pressure will result in ansmaller quantity of gas present. Therefore, it is conservative to have the room be initially at its highest credible steady state temperature. The initial room temperature assumed in other calculations is 85 'F, which likely originated from Bechtel Specification 6118-M-41 (Ref 4.10). Current log sheets (PBF-2032/2033, Ref 4.13) state that the maximum allowable battery cell temperature (in -the Vital Switchgear Room, which shares ventilation with the AFW pump room) is 85 'F.

It can be expected that after the AFW pumps start, the room will likely increase'in temperature. This would result in 'a higher accumulator pressure, which would ultimately reduce' the'required size of the accumulator.

Therefore,'it will be assumed that the roomrtemperature will not increase due to heat generated by running AFW pumps. This is a conservative assumption.

It should be noted that temperature has a very small effect on the outcome of this calculation. The temperature effects tend to cancel out since the accumulator and the AOV will be at the same temperature.

32. Total airleakage is assumed to be a constant value of 0.15 SCFM.

Basis: This accounts for leakage past the check'valves, through all fittings, and through the air operator. This is less than the 05 SCFM that was assumed by the original calculation for sizing nitrogen supply for the MDAFP discharge AOVs (Ref 4.2). This is acceptable since all tubing required to maintain the pressure in this portion of the system was installed with high-quality, safety-related stainless steel tubing and fittings, and redundant check valves were installed upstream of the accumulators per MR 02-001 (Ref 4.4). Furthermore, leakage through the fittings and past the check'valves 'was tested following modification installation (Ref 4.4) and will be checked periodically to verify iha tit is below 0.15 SCFM (Ref 4.1 1). 'Also, there is no demand on the system when the AF-4002 valve is closed, and the only bleed-through present is a very minor weepage from the valve regulator (there are no positioners installed on these AOVs). This regulator weepage has been measured by previously performed drop 'tests after MR 02-001 was installed, and the weepage rate was confirmed to be less than 0.05 SCFM (Ref 4.4). This assumed leakage is an appropriate value representing a very large ,amount of leakage is easily checked. This leakage is assumed'to be constant throughout the duration of AOV operation, which is an additional conservatism since the actual leakage rate will drop with reduced accumulator pressure. Acceptance criteria in'Il 8C/9C will represent a-leakage value that is less than 0.15 SCFM.

3.3. The valvewill be required to fully stroke 10 times per hour.

Basis: This is consistent with assumptions made in calculation M-09334-266-IA.1 (Ref 4.2) for operation of the MDAFP discharge control valves. The original decision to utilize this value originated in an email dated

__ -I __- .

CALC 2001-0056 Rev 02 RCC :10/2412003 Page i of 13'

4.0 REFERENCES

4.1. Bechtel P&ID 6118 M-217 Sh. 1, Auxiliary teedwater System 4.2. 'Sargent & Lundy Calculation M-09334-266-lA.1, Rev. 0

43. STPT 14.7, Secondary Systems Instrument, Service, and Breathing Air 4.4. MR 02-001 - TDAFP Mini Recirc Valve (1/2AF-4002) Instrumcnt Air Accumulator Addition 4.5. ;Bechtel P&ID 6118 M-209 Sh. 4, Instrument Air 4.6. Fundamentals of Engineering Thermodynamics, 2"'Ed.,M. Momn and H. Shapiro, 1992 4.7. Copes-Vulcan Drawing E-336528 Rev 0, Model D-100-160 Oper. -2" 1513# ASME Std. Valve Assembly 4.8. Lefttr' from Robert Fetterman, Copes-Vulcan f6R6b-Chliamaii, PBNP,`daied 1/11/2002 (AtJachlment1) 4.9. Email from Jack Hammers to Dave Godshalkdated 6/2/97 (Attachment 2) 4.10. Bechtel Specification 6118-M41, Sheet Metal Duct Work 4.11. IT 8C (9C),TDAFPMini Recire Valve 1(2)AF4002 Accumulator Check Valve 1(2)AF-173 Pressure Decay Test-Unit'1(Unit2) 4.12. Crane Technical Paper 410, Flow of Fluids through Valves, Fittings, and Pipe 4.13. PBF-2032(2033). Daily Logsheet-Turbine Building Log Unit 1 (Unit 2) 4.14. CMP 2.5.2.1, Setup Parameters for Category I Air Operated Valves 5.0 INPUTS 5.1. The required air pressure to stroke'1/2AF4002 full open is 65 psig, as set by MR 02-001 (Ref 4.4). This will also 'be used as the final pressure in the accumulator tank after the required number of valve strokes to determine the necessary tank volume.

5.2. The swept volume of a Copes-Vulcan D-100:160 valve'actuiatorintludirig'dead'volume, is'291 'in 3 (Ref 4.4)

- CMP 2.5.2.1 (Ref 4.14) controls setup of valve,,and will be revised to reference this calculation: . ,v,">,

53. The total length of the 3/8" diameter instrument air tubing' between the solenoid valve and the AF-4002 RV . .

actuator that is vented is 100" (per walkdown)

/CX 5.4. The accumulator tanks installed by MR 02-001 have' a volume of 150 gal (Ref 4A) // 'e C dxO it i 2 e 5.5. Standard conditions are defined as 60 IFand 14.7 psia (Ref 4.12) S 4 d 5.6. Actual lengths of tubing pressurized during testing is 360" for Unit I and 960" for Unit 2 (per walkdown) e /; .G 5.7. The tubing installed by MR 02-001 is 3/8" tubing with 0.065" wall thickness'(Ref 4.4) 5.8. The AFW pump room temperature is 90 °1 (Assumption 3.1)