ML17229A671
| ML17229A671 | |
| Person / Time | |
|---|---|
| Site: | Saint Lucie  |
| Issue date: | 03/20/1998 |
| From: | Stall J FLORIDA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-90-05, GL-90-5, L-98-75, NUDOCS 9803300267 | |
| Download: ML17229A671 (15) | |
Text
CATEGORY 1 REGULA'I dY INFORMATION DISTRIBUTIO SYSTEM (RIDS)
ACCESSION NBR:9803300267 DOC.DATE: 98/03/20 NOTARIZED: NO FACIL:50-335 St. Lucie Plant, Unit 1, Florida Power
&, Light Co.
AUTH.NAME 'UTHOR AFFILIATION STALL,J:PJ, Florida Power
&. Light Co.
RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
DOCKET 05000335
SUBJECT:
. Submits suppl 1 of Interim Relief Recpxest 17 re in-svc-insp plan for third 10-Yr interval.
DISTRIBUTION CODE: A047D COPIES RECEIVED:LTR ENCL SIZE:
TITLE: OR,Submittal: Inservice/Testing/Relief from ASME Code GL-89-04 NOTES:
RECIPIENT ID CODE/NAME PD2-3 LA GLEAVES,W COPIES LTTR ENCL 1
1 1
1 RECIPIENT ID CODE/NAME PD2-3 PD COPIES LTTR ENCL 1
1 E
0 INTERNAL: ACRS LE CENTER 1
CS -2~ TRACT RES/DET/EIB EXTERNAL: LITCO ANDERSON NRC PDR AEOD/SPD/RAB NRR/DE/EMEB OGC/HDS3 RES/DET/EMMEB NOAC 1
1 1
1 1
0 1
1 1
1
~
D E
NOTE TO ALL "RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WASTE. TO HAVE YOUR NAME OR ORGANIZATION REMOVED FROM DISTRIBUTION LISTS OR REDUCE THE NUMBER OF COPIES RECEIVED BY YOU OR YOUR ORGANIZATION, CONTACT THE DOCUMENT CONTROL DESK (DCD)
ON EXTENSION 415-2083 TOTAL NUMBER OF COPIES REQUIRED:
LTTR 14 ENCL 13
\\
h I
Florida Power & Light Company. 6351 S. Ocean Drive, Jensen Beach, FL 34957 FPL March 20, 1998 L-98-75 10 CFR 50.4 10 CFR 50.55a U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 RE; St. Lucie Unit 1 Docket No. 50-335 In-Service-Inspection Plan Third Ten-Year Interval Supplement 1 of Interim Relief Re uest 17 On March 2, 1998, Florida Power and Light Company (FPL) requested approval of interim relief request 17, Main Feed Isolation Valve Bypass Line Repair.
Relief request 17 is needed to support the temporary non-code repair which installed an engineered mechanical clamp to enclose a feedwater/steam leak at a socket welded elbow fitting on the one inch bypass line for MV-09-7, main feed isolation valve. This supplement of relief request 17 is a complete replacement for our original request submitted by FPL letter I 98-068 on March 2, 1998.
Supplement 1 provides the additional commitments verbally requested by the NRC-NRR project manager for St, Lucie on March 6, 1998.
On February 27, 1998, a small feedwater/steam leak was noted on a one inch socket welded elbow fitting located on the downstream side of the bypass line. The leak was characterized as a feedwater leak creating a visible jet of steam about two feet long creating a moist area on the adjacent lagging and scaffold.
The leak is considered minor in nature (approximately three gallons per hour based on collection of the mist). The leak is unisolable and is subject to full main feedwater header pressure during plant operation.
FPL has determined that an ASME code repair is not practical in that the affected piping is unisolable.
A plant shutdown and cooldown would be required to perform a code repair on the leaking pipe which would unnecessarily cycle plant systems and components.
Relief request 17 approval is requested to support the use of an engineered clamp for the temporary repair of pressure boundary leakage on the 1A main feed isolation valve bypass piping.
Use of the relief request would allow the temporary repair of the piping with Unit 1 in service.
98033002b7 980320 PDR ADQCK 05000335 8
)p+ t
r
~
~
~
I
~ ~
(
St. Lucie Unit 1 Docket No. 50-335 L-98-75 Page 2 This letter contains the following regulatory commitments.
The clamping device, constructed in accordance with this relief request, will remain in service only until the next cold shutdown of sufficient duration or the next refueling outage (SL1-16), at which time the defect willbe repaired or replaced in accordance with IWA-4000. While the temporary repair is in place, it will be visually inspected by plant personnel daily for signs of degradation.
When the code repair is implemented, the failure site willbe examined, the root cause of the failure determined, and the results of the root cause analysis willbe submitted to the NRC.
Please contact us ifthere are any questions about this submittal.
Very truly yours, J. A. Stall Vice President St. Lucie Plant JAS/GRM Attachments cc:
Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, St. Lucie Plant
St. Lucie Unit 1 Docket No. 50-335 L-98-75 Attachment 1 Page 1
Relief Request No. 17 Main Feed B ass Line Re air Com onent Identification:
1A main feed isolation valve bypass one inch line Class 2 C~dR Section XI 1989 Edition IWC-4000 which refers to IWA-4000 Repair procedures - Requires that repairs be performed in accordance with this Article.
Code Re uirement From Which Relief Is Re uested:
During operation, leakage was detected on the 1A main feed isolation valve bypass line.
Relief is requested from the repair requirement of the ASME Boiler and Pressure Vessel Code Section XI 1989 Edition, Articles IWC/IWA-4000.
Basis for Relief:
See Attachment A~IR a)
FPL willperform a temporary non-code repair on the 1A main feed bypass line using an engineered clamp as described in the basis for relief. This repair willperform the function of leakage prevention, and will remain in place no later than the next cold shutdown of sufficient duration or the next refueling outage (SL1-16).
At that time, a Code Repair/Replacement will be performed.
b)
While the temporary repair is in place, it will be inspected visually by plant personnel daily for signs of degradation.
c)
When the code repair is implemented, the failure site willbe examined, the root cause of the failure determined, and the results of the root cause analysis will be submitted to the NRC for information.
St. Lucie Unit 1 Docket No. 50-335 L-98-75 Attachment 1 Page 2
Im lementation Schedule:
The remainder of St. Lucie Unit 1 Cycle 15. At the next cold shutdown of sufficient duration or the next refueling outage (SL1-16), the defect will be repaired of replaced in accordance with IWA-4000.
Attachments:
Engineering basis for performing a temporary non-code repair.
St. Lucie Unit 1 Docket No. 50-335 L-98-75 Attachment 2 Page 1
Basis for the Relief 1.0 Background/Purpose Operational leakage was discovered in the socket weld joint for the downstream elbow of the MV-09-7, main feed isolation valve (MFIV)bypass line. This elbow is adjacent to V09188. The leak is characterized as a feedwater leak creating a visible jet of steam about two feet long creating a moist area on the adjacent lagging and scaffolding below. The leak is considered minor in nature (approximately three gallons per hour based on collection of the mist), but needs to be stopped to minimize further steam cutting of the MV-09-7 bypass line elbow weld. This evaluation addresses the temporary clamping of the steam leak with a leak repair enclosure to encapsulate the elbow and a clamp to absorb the axial loading adjacent to the affected socket weld.
Generic Letter (GL) 90-05 states that for code Class 1 and 2 piping, a licensee is required to perform code repairs or request NRC to grant relief for temporary non-code repairs on a case-by-case basis regardless of pipe size.
This evaluation provides the technical basis for making a non-code repair.
2.0 Basis for Relief Structural Inte rit The leak repair enclosure and clamp is considered a non-code repair to stop the leakage to prevent further steam cutting of the MV-09-7 (Figure 1) bypass line elbow weld. The leak is located in an oval pinhole in a socket weld near the fitting edge.
In accordance with GL 90-05, the overall design of the leak repair enclosure willassume a postulated full circumferential severance of the socket weld at the defect location.
The design pressure and temperature of the subject piping is 1100 psig and 500'F which is consistent with the feedwater (FW) system piping downstream of the MFIV. As the enclosure design meets or exceeds these design requirements, the leak repair enclosure is capable of withstanding design conditions consistent with FW system pressure boundary components.
The system fluid is demineralized condensate which is compatible with the enclosure and clamp materials.
Enclosure and Clam Desi n Figure 2 and Figure 3 provide the design details for the temporary leak repair enclosure and clamp.
The enclosure is designed for the conditions specified above.
The enclosure (Figure 2) completely envelopes the elbow fitting and weld and therefore the clamping device size willaccommodate any projected growth of the flaw.
St. Lucie Unit 1 Docket No. 50-335 L-98-75 Attachment 2 Page 2
The materials of construction are acceptable for the application.
The enclosure is made of SA 516 Gr. 70 carbon steel with SA-193 Gr B7 studs and SA-194 Gr. 2H nuts.
A friction clamp (Figure 3) provides a means of absorbing the axial load in the extremely remote possibility that the flaw propagates circumferentially around the weld joint. The enclosure design is based on stress limits in Table NC-3321-1, and meets Level A Service Limits of Section IIIusing normal system operating conditions, and assuming postulated full circumferential severance of the pipe at the defect location.
The enclosure is mechanically clamped to the pipe with a friction factor not exceeding 0.3 and designed to produce a friction load five times the slippage load.
Figure 4 and Figure 5 show plan and elevation views of the installed engineered clamp.
Review of the enclosure design has been performed to ensure the enclosure meets the intent of GL 90-05.
Based on this review, it has been concluded that the subject temporary leak repair enclosure and clamp is suitable for the intended application and capable of performing the design functions specified.
As the defect is located in a weld zone, the repair enclosure completely surrounds the subject fitting, and the enclosure design will accommodate full circumferential severance of the socket weld at the defect location.
A plan for monitoring defect growth in the area immediately adjacent to the clamping device is not required.
Pi e Stress/Su ort Anal sis The bypass line is depicted on Drawing 8770-G-125 Sheet BF-M-6.
Engineering walkdown has shown that the perpendicular stub connections to the process line is approximately six inches long.
The distance (parallel direction to the process line) between the two stub connections is 34 inches as per EMDRAC 8770-7002.
The proposed leak repair enclosure will be installed over the leaking elbow downstream of valve V09188. The weight of the leak repair enclosure is less than 40 lbs and the clamp weighs 10 lbs (Figure 1). A stress analysis of the bypass line and the affected process line with the additional weight of the leak repair enclosure and clamp has been performed in calculation BF-0659A.
The results show that the additional weight does not adversely affect the Code pipe stress requirements and no additional supports are required.
Tem orar Clam Sealin Com ound The sealant used will be FSC-N-3B, or better.
The sealant is thermal setting and is injected while the system is at operating pressure and temperature.
The volume of injected sealant is based on the calculated volume of the leak repair enclosure.
The maximum volume and the maximum injection pressure, which includes the extrusion pressure (pressure required to push the sealant into the mold), plus the molding pressure (the pressure required to fill the mold) and the operating pressure (pressure that must be
St. Lucie Unit I Docket No. 50-335 L-98-75 Attachment 2 Page 3
overcome to fillthe leak repair enclosure), ensures that the sealant does not overcome the system pressure and enter the system.
This injection method precludes "mainlining" of the sealant into the system.
These leak repair methods have proven effective in sealing leaks on similar components with similar failures.
3.0 Summary The installation of the temporary leak repair enclosure willnot introduce any new failure modes for the main feedwater system.
The leak repair enclosure is a passive device and does not perform any active safety function.
In addition, the temporary leak repair enclosure has been designed for the appropriate loading conditions, and as such, its failure is not assumed.
Structural integrity of the affected piping system is not affected by the installation.
The injection material and injection pressures have been analyzed to ensure that no contaminants are introduced into the system, and that system operation is not adversely affected.
Based on the above, the temporary clamping of a feedwater leak at an elbow in the one inch bypass line for MV-09-7 does not alter or jeopardize any of the design described in the UFSAR.
PL
~i
+~I 0
yy
)IL s~
s t
~
M 5%
~g
. ae
~ae 1
I I
)I
~
tt I
I m~~hha. -"
I ep A
.~
~
~
~
~ 4
RS/8 I4)Il/16'1/2't) tt)1.260' I e)
R7/8'/8'1/2'/8'-9UN Q,A,'. REVIEWD AND APRRHVED~
~/~w Ni 3/8'1 1/4'9
))ur>6 3 6" R2 3/C'2 1/Bc NOTES)
S/8' 11/16'/8'-11NC 5 STUDS I~ SAF'ETY RELATEDt
- 2. PROCEDURE NUMBER N-98086.
- 3. COMPONENT DESIGNATION
- V09188,
- 4. INJECTION POINTSc DRILL THRU t43/16'. DRILL AND TAP F'R 3/8'-16NC X 3/8'EEP.
2/HALF.
- 5. PEENING GROOVEt 1/8' 1/8' 60'.
ED FOR FABRICATION MATERIAL UST:
(CARBON STEEL)
SA-516 GR.-70 N/A N/A SA-193 GR.-B7 SA-194 GR.2H SA-516 GR.-70 N/A PLATE:
FITTING:
PIPE:
STUDS:
NUTS:
TUBE LUGS:
PACKING:
pLjRM~~[TE ENGINEERlNG 6 + ~axe.~
A KNE8 cclcppYf ftFKQ 4ec)~ Ctll)cct~ I%I Ctcl)~
e
- 6. ALL DIMENSIONS ARE: TYPICAL UNLESS SPECIFKD, cc)
- 7. TUBE LUGS WILL BE WELDED AT THE CUSTOMER WELDING SHOP.
3S LBS 25-Sr'r~ ~
FSC-N-38 68 n
t-"
uO<
~~ ~ 0
+
~ 0 ~
~-Ze Q
A ~c oo
~ o~
@ad t/t4 ncN:ncaa "aeeP
+t
-0 DEKE 1 100
~
BOB JACQUES DCXtl 5 os CAI I REGION WPSO002 FLORIDA POVfER 8c UGHT ST LUCIE NUCLEAR ST
~ 02/27/98 4 ASAP
~ $ 1 4
Fl A-625 ccccc~
SHEET 1/2
h@3/4'3/4'1 3/8'
~1.260'J h
t P.1 1/8'-
34 1 13/16' 5/8'OTE S1 1'; ONE 'FRICTIQN'CAL'HP IS REQ'3,
'2".:-(2').:5/8;-.-'.11NC
.: "12..'LONG;.-3'Worj+c. c4'i>>y Qsts+~
ls~ A lgs.
8 2
. f-man-.:)0.',LOS.:. - '::.'.
GA-625
. ~
gE'a5a1
~
9aaaa~
a>8 4 4
. i-z 1
1.5
~
02/27/Sa
~'aP
~ 2/2.
St. Lucie Unit 1 Docket No'. 50-335 L-98-75 Attachment 2 Page 7
PLOW 0,
0 0
FRICTION CLAMP LEAKREPAIR ENCLOSURE 0 0 LEAKINGSOCKET WELD MV-09-7 BY-PASS Figure 4
St. Lucie Unit 1 Docket Ho. 50-335 L-98-75 Attachment 2 Page 8
1/2" 5 5/16" 0
1/4" MV-09-7 BY-PASS Figure 5