ML17229A163

Part 21 Rept Re 2-1878 Globe Piston Check Valves.A/Dv Plans to Include Philosophy of Both Enhancement W/Smaller Piston Check Valves.A/Dv Evaluated Found Condition of Piston Check Valve,Stuck Open

ML17229A163
Person / Time
Site:	Saint Lucie
Issue date:	11/27/1996
From:	Knecht W ANCHOR/DARLING VALVE CO.
To:	Carter J NRC
References
REF-PT21-96 NUDOCS 9612160224
Download: ML17229A163 (11)

Text

CATEGORY j.

REGULAT INFORMATION DISTRIBUTIONSTEM (RIDE) g1 ACCESSION NBR: 9612160224 DOC.DATE: 96/11/27 NOTARIZED: NO DOCKET '0 SCIL:50-335 St. Lucie Plant, Unit 1, Florida Power 6 Light Co. 05000335 50-389 St. Lucie Plant, Unit 2, Florida Power 6 Light Co. 05000389 AUTH. NAME AUTHOR AFFILIATION KNECHTFW.G. Anchor/Darling Valve Co.

RECIP.NAME RECIPIENT AFFILIATION CARTER,J. NRC No Detailed Affiliation Given

SUBJECT:

Part 21 rept re 2"-1878 globe piston check valves.A/DV plans to include philosophy of both enhancement w/smaller piston check valves.A/DV evaluated found condition of piston check valve, stuck open.

DISTRIBUTION CODE: IE19T COPIES RECEIVED:LTR ENCL SIZE:

TITLE: Part 21 Rept (50 DKT)

NOTES:

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U E

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Anchor/Darling Valve Company ~ Williamsport, PA 17701 W. G. KNECHT Technical Director November 27, 1996 Mr. Jerry Carter US NRC Events Assessment Branch Washington DC 20555

Subject:

A/DV l878 Class Piston Check Valves

Dear Mr. Carter:

Per our discussion this date the enclosure is the latest copy of our report to FPSL regarding the piston check valve problem.

Should you have any questions please do not hesitate to call Floyd Bensinger, our Engineering Manager, or the writer.

Sincerely, ANCHOR/DARLING VALVE COMPMY u,rlW4f-William G. Knecht Technical Director WGKjs cc: F. A. Bensinger Enclosure 96i2i60224 96ii27~i PDR ADOCK 05000335 8 PDR

Anchor/Darling Valve Company Page 1 of 4 701 FIRST STREET P.O. SOX 3428 WILUAMSPORT, PA 177014428 (717) 3274800 FAX: (71 TJ 3274805 Florida Power and Light Company St. Lucie Plant P.O. Box 128 Fort Pierce, FL 24954 November 20, 1996 Attention: D.J. Denver St. Lucie Engineering Manager

Subject:

A/DV 2"-1 8780 Piston Check Valves

Reference:

1. FP&L JPN-SPSL-96-0372, August 16, 1996 Letter

2. NDV S.O.'s ET401 and RZ814

3. NDV Test Report No.'s RZ814, Test Report of Flow Test on a 2"-18780 Globe Piston Check Valve, October 2, 1996 Gentlemen:

NDV apologizes for the delay in responding to the referenced FP&L letter. We had hoped to receive application responses to our notification letters but as of this writing we have not received any complete information.

NDV has performed a design review of the piston check valve with the intent to address the functional and re-assembly problems experienced at St. Lucie. The following areas were addressed as noted:

A. Pr re e I/Bonn Are I m Bonnet Retainer Capscrews FP8L reported having difficulty in sealing the ADVanseal using the capscrew without pressure. The current capscrew is a 5/16" diameter capscrew. A 1/2" diameter capscrew will be used in the future. This will provide approximately three (3) times the gasket load.

2. Galling of the Bonnet Retainer Threads FPBL has experienced galling of the bonnet retainer threads. The current retainer is made of 316 stainless steel with chrome plated 12 series threads. NDV is evaluating replacing this design with a 17-4PH bonnet retainer (no chrome plating) with 8 series threads.

Assuming successful completion of the new bonnet retainer evaluation, this design will be put in place.

A/DV plans to include the philosophy of both enhancement with the smaller piston check valves. These two (2) enhancements will affect inventory and part interchangeability.

B. CI nin D in fV lv s Prior hi men NDV has evaluated several methods to assure complete drying of the piston check valves prior to shipment, i.e. disassembly, baking, etc. We have concluded that the most effective method is to disassemble the valves after hydrostatic testing, dry the parts and reassemble without the gasket and anti-rotation pin (Part No. 258) installed. The gasket and anti-rotation pin will be packaged with the valve and a tag placed on the valve requiring installation of these two (2) parts after valve installation.

V Iv Perf rm nce F n ional I m Disc Guide Area of Body Neck Bore We evaluated this area to determine if the body guides could be improved. Several methods were evaluated, i.e., steeving the body bore with hardened material, reshaping the exhaust port, etc. All methods are costly. The conclusion was reached that the above changes were cost prohibitive and the better resolution is to use a smaller valve for oscillating flow application in order to place the disc in a more open position where it is better guided by the body.

C. Valve Pert rmanO Func Ion I Items (Conttnued)

2. Disc - Body Material Couple tt was stated by FP8L that fretting is more apt to occur where a large difference in material hardness exists. A/DV selected the body-disc material couple for wear resistance, galling resistance and castability, weldability of the bodies.

A more important factor to reduce the potential for fretting is reduced stress levels. NDV does not plan to change the body or disc materials. As discussed in A.1. above and in the later root cause analysis, use of a smaller valve would resolve this situation.

Rough Machining left in the Body Neck Bore In May, 1993, NDV had changed its rough machining process to setup and rough cut the neck bore and seat pocket using the same setup method and single point tooling-boring as the finish machining process. Prior to this time the neck bore was rough machined on a radial drill. This drilling process was not always performed on the same centerline as the final machining and the drill had a tendency to tail off center. This area has been resolved as described above in May, 1993.

Ratio Guide Length - Disc Diameter NDV's design criteria limits the potential disc tilt to less than 1/2'nd requires a ratio of one (1) or greater for the disc, guide length to diameter.

The 2"-1 878¹ Piston Check disc has a ratio of 1.12:1. Both NDV's design criteria and the 2"-1 878¹ design are representative of NDV and competitive valve designs which have been proven to be successful in most services.

Roo C s NDV evaluated the as found condition of the piston check valve that stuck open.

To assist in our root cause analysis, we performed flow tests on two (2) 2"-1878¹ Piston Check valves (one (1) valve returned from FP&L, S/N ET401-9-6).

Reference No. 3 Report, enclosed, documents the task and results. The testing was performed to evaluate valve performance at various forward flow rates. The test conclusion was the valve always closed when forward flow ended.

Eg As a result of our evaluation of the FPBL failed valve and our testing, we have concluded that the root cause is the disc oscillation, caused by the reciprocating pump, causing fretting to take place in the valve body disc guide area. The fretting area provides a configuration in the body guide that allows the disc to stick open without forward flow and with reverse flow.

A/DV's recommendations to eliminate the valve operational problem are (preferred listed first):

A. Use of in-line check valves in reciprocating pump applications. This valve design provides better wear resistant materials as disc guides throughout the entire valve stroke.

~~

Use of smaller piston check valve (valve size or reduced port) in reciprocating pump applications to more fully open the disc where better body-disc guiding is available. Attached are graphs of flow rate versus disc position and Cv versus disc position to be used to evaluate T-pattern piston check valve size selection. Where a smaller T-pattern piston check valve

~

produces too high a pressure drop, use of a Y-pattern piston check valve may resolve this concern.

T-pattern and Y-pattern piston check valves and in-line check valves are within A/DY's product lines. Availability of Y-pattern piston check valves is sclleduled for the second quarter of 1997.

lf further discussion is required on the above, please feel free to contact us.

ANCHOR/DARLINGVALVECOMPANY Floyd A. Bensinger, P.E.

Manager - Engineering bcc: J. Chappell G. Parks T. Johnson J. Tarbutton W. Knecht'G; H. Wescott Kneiser F. Velez R. Maietta

2" 8c Smaller T Piston Check Valves ~ ~ FAB 01-Nov-96 Flow Coefficient (Cv) vs. Disc Position 50 40 30 C

EJ 0

20 10 0

0% 20% 40% 60% 80% 100%

Disc % Open 1/2" PCs + 3/4" Bc 1" PCs O 1-1/2" PCs 2" PCs

2" 8c SmaIIet T Piston Chec k Va Ives ~ ~ FAB 01-Nov-96 Air Flow Rote (cfm) vs. Disc Position 350 300 250 200 150 100 50 0

0% 20% 40% 60% 80% 100%

Disc  % Open 1/2", 3/4" 8c 1" P.Cs + 1 1/2" PCs <> 2" PCs

2" Bc Smaller T Piston Check Valves ~ ~ FAB 01-Nov-96 Water Flow Rote (gpm) vs. Disc Position 260 240 220 200 180 160 140 120.

100.

80 60 40 20 0

0% 20% 40% 60% 80% 100%

Disc % Open 1/2", 3/4" Bc 1" PCs + 1-1/2" PCs <> 2" PCs

PART CTY DESCRIPTION MATERIAL NO REVISIONS 001 I BOOT SASS I~5M DELETED MOTE 5: OY S N, 002 I BONNET SA47~16 ADDED Mofds e THRU lo.

004 I DISC SA65IP560 TYPE I CUSTOMER NOTEADOEO UNITS ACW A ANO VALVE DATA SHEET NO.

015 I SEAT RINC A276.S21600A DELETED CUST. P.o. No. dc I HI2 050 I PRESSURE SEAL CASKET GRAPHITE MOVED A/OV S.o. No. TALE 052 I SPACER RING A47~16 BLOCK: DELETED "CLOSE 054 I BOMNET RETAINER SA479-51 6 215 I BONNET CAPSCREW A574 256 I ANTHIOTATION PIN AISI 502 (SPRINC TTPE 260 I WIRE ER516 545 I NAMEPLATE AISI 504 545 I IDENTIFICATION PLATE AISI 504 429 I SPRING INCONEL X NOTES I. VALVE IS ASME CLASS I PER 1965 ASMK SKCTIOM R 7. 4 - ASMK PRESSURE BOUNDARY PART

2. APPROX VALVE WEIGHT 24 LBS d. CRACKIMC PRESSURE 5 PSI

5. APPROX CV 56 9. ANSI 1676 STANDARD INTERPOLATED PRESSURE CLASS

4. PISTON CHECK VALVE DESIGNED FOR MOUMTINC IN A lo. HYDROSTATIC TEST INFORMATION:

HORIZONTAL RUN OF PIPE WITH VALVE ENDS HORIZONTAL SHELL SEAT AND BONNET ON TOP PRESSURE (PSI) 5775 4956

5. VALVE DESICN PRESSURE IS 2755 PSI AT 6do F ALLOWABLK LEAKAGE (CC/HR) 0 3

d. MINIMUM FLOW DIAMDER 1.500 DURATION (MIN) 10 5 SEAT RING INSIDE DWlETER ~ 1.500 25d 054 215 CO 052 050 002

)C CI O IL O!

~o 0 O oo5 W

~ FO El 429 0 O.

Vl 004

>C 001 O

I:

IL 015 FLORIDA POWER R LIGHT COMPANY ST. LUCIE UNITS I R '2 SPECIFICATION No.: MN 5.06 VALVE DATA SHEKfl YDSPSL&IO ' Y. ~

ANCHOR DARLING VALVE COMPANY 2"-1878

.52 MIM .520 MIN SECTION AA Zeo FULL PORT 545 SOCKET ENDS STAINLESS STEEL FLOW 546 PISTON CHECK VALVE df NONWOBALT TRIM ON BY.'AlQHI P 9AIO 00302 10 I 92 I T'~l 'T~

QI 9ll 21 2P S 71 O ET401% APPO 6II RFB ega IO-IIHI2 I 2 5 4 5 ~ 7 6