ML20238F279
| ML20238F279 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 09/10/1987 |
| From: | Bailey J WOLF CREEK NUCLEAR OPERATING CORP. |
| To: | Martin R NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM), NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| ET-87-0272, ET-87-272, IEB-87-001, IEB-87-1, NUDOCS 8709160055 | |
| Download: ML20238F279 (11) | |
Text
- - _ _ _-__
LF CREEK W@ NUCLEAR OPERATING C John A. Bailey Vios President Engineer 6ng and Technical Services ET 87-0272 U. S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 Mr. R. D. Martin, Regional Administrator U. S. Nuclear Regulatory Commission legion IV 611 Ryan Plaza Drive, Suite 1000 Arlington, Texas 76011 Subj ect:
Docket No. 50-482:
Response to NRC Bulletin 87-01 Gentlemen:
The purpose of this letter is to transmit Wolf Creek Nuclear Operating Corporation's response to NRC Bulletin 87-01,
" Thinning of Pipe Walls in Nuclear Power Plants".
The Bulletin requested licensees to provide information concerning their programs for monitoring the wall thickness of pipes in condensate, feedwater, steam, and connected high-energy piping systems, including all safety-related and non-safety-related piping systems fabricated of carbon steel.
The attachment to this letter provides the information requested by the NRC.
If you have any questions concerning this matter, please contact me or Mr.
O. L. Maynard of my staff.
Very truly yours, John A. Bailey Vice President Engineering and Technical Services JAB /jad Attachment 8709160055 870910 cc: P0'Connor (2 PDR ADOCK 05000482 JCummins O
PDR f,g
_,, _ s _ _,, - >,
An Equal Opportunny Emp6 oyer M FHCNET 1
n l
4 1
STATE OF KANSAS
)
j
-) 'SS
' COUNTY 0F.COFFEY
)'
John A..' Bailey, of lawful. age, b'eing first duly svorn upon oath says that he is Vice-President' Engineering and Technical Services'of' Wolf Creek-Nuclear-
.{
Operating Corporation;.that he has read the foregoing document and knows the content thereof; that he has executed that same for and on behalf of said Corporation with full _ power and authority to do ~ so; and that the. facts'
-j therein. stated -are :true and correct 'to the best of his' knowledge, information and belief.
By John A. Bailey
/
Vice-President Erfgineering any.
Technical Services SUBSCRIBED and sworn to before me this /0 day.of 6ep -
, 1987.
7 m14 hLdn
.,.=**......n.9.< hc
.v.
Notary Public
.a.
i/a
'p Ydb O.,
Expiration Date f
f:
..y........g..,
1
L
. Attachment'to ET 87-0272
~'
September. 10, 1987
' Page 1 of 8 Wolf Creek Nuclear Operating Corporation's (WCNOC) Response to NRC' Bulletin 87 - Thinning of Pipe Walls in Nuclear Power Plants"-
Introd uction.
On July 9, 1987,.
.the' Nuclear. Regulatory Commission. issued NRC Bulletin
.:87 -01 i
'" Thinning of Pipe Walls in: Nuclear Power Plants", -to -all nuclear
- power plants' holding an operating license or a. construction permit.
The purpose of the : Bulletin. was to request information concerning licensee's-prograus for. monitoring the-thickness of: pipe walls in high-energy single-phase andf'two-phase carbon steel piping-systems.
. This request for information. was primarily due to conclusions from investigations into the failure of-main - feedwater piping at the Surry Nuclear Power Station on
' December 9, 1986.
Requested Information This, report addresses specific information which' was requested in NRC Bulletin 87-01.
The following. paragraphs list the requests of the Bulletin followed by the WCNOC response.
1.
Identify f the codes or standards to which the piping was designed and
~ fabricated.
For sa fety-related systems, the. applicable code for _ design and fabrication is ASME Section III, Class 2-and 3.
The design and-fabrication of non-safety-related systems is' in accordance with ANSI B31.1, NFPA, and AWWA codes.
2.
Describe the scope and extent of your programs - for. ensuring that' pipe wall thicknesses are not reduced below 'the miniminum allowable thickness.
Include. in the description the criteria that you have established. for:
a.
selecting points.at which to make thickness measurements b.
determining how frequently to make thickness measurements c.
selecting the methods used to make' thickness measurements d.
making replacement / repair decisions I
h_._____.____.___..__
__.___m__
e 4
- Attachment to ET187-0272.
i Saptember.10, 1987.
Page 2 of.8
{
1The following is: an-outline. which' describes in general the Wolf Creek
~'
Generating Station (WCGS) Erosion / Corrosion.Honitoring Program, with the
. phases representing.the order in which portions of the overall program
.will.be instituted:
Phase 1.-
Identify an. initial group of components. withe potential-for.
. experiencing. pipe wall thinning problems.
Phase 2.
Survey /Heasure wall thicknesses-of components which ' were identified ~ in Phase 1.
Phase 3; Evaluate initial field-inspection results from Phase-. 2.
Repair / replace components as necessary.
Phase =4
.As necessary,. identify additional ~ components with potential pipe. Wall. thinning problems.
' Phase 5.
Continue identification and monitoring of suspect :' components;
-revising
'as.necessary, based on.~results from in-house inspections as 'well as industry experiences.
The -following is a' description of the criteria used for specific aspects of the WCGS Erosion / Corrosion Program:
a.
selecting points at which to make thickness measurements The selection criteria for identifying points L at which to make thickness measurements includes.the following factors: temperature,
- velocity, geometry, pH, and. oxygen.. An additional parameter identified as a flow condition factor based on the temperature and pressure of the fluid (i.e. steam, two-phase, saturated liquid.. or subcooled. liquid) is also considered.
Further discussion of these factors-is. given in response to. Items 3a through: 3f below.
Consideration uis also givan to the frequency ' of.,.use, pipe size, operating pressure, and potential impact of a failure on personnel safety, public safety, and plant availability.
b.
determining how frequently to make thickness measurements The trending / predictive reports ' generated for each examination performed.for the Erosion / Corrosion program are. evaluated and examination frequencies are adjusted based on the results of the examination.
If examination results show either minimal changes or significant changes in pipe wall thickness, the examination frequency may be decreased or increased as necessary.
c.
selecting the methods used to make thickness measurements l-In accordance with the recommendations contained in EPRI NP-3944 -
l
" Erosion / Corrosion in Nuclear Plant Steam Piping:
Causes and Inspection Guidelines",
WCGS will utilize manual Ultrasonic Test (UT) techniques to detect areas of Erosion / Corrosion.
This technique-will be supplemented by manual or remote visual l
examination when possible.
4
I Attachment to ET 87-0272 September 10, 1987 Page 3 of 8 d.
making repair / replacement decisions l
If a component is found to be less than or equal to 87.5 percent l
Nominal Wall Thickness (TNOM), that component and the results of the field examinations will be evaluated in an expedited manner to determine the minimum acceptable wall thickness.
This evaluation is based on maximum operating parameters, system piping rigidity, and structural and stress factors.
If a component is found to be less than or equal to 20 percent of T that component will be repaired wiUO", existing station procedures for or replaced in accordance safety-related and non safety-related systems.
3.
For liquid-phase systems, state specifically whether the following factors have been considered in establishing your criteria for selecting points at which to monitor piping thickness (Item 2a):
a.
Piping material Based upon the selection criteria stated above, all carbon steel piping systems considered susceptible to Erosion / Corrosion are monitored.
b.
Piping configuration Specific selections of systems identified as having a potential for Erosion / Corrosion are being reviewed with respect to piping configuration.
Guidance for this review is being drawn from Virginia Power's Surry Program and EPRI recommendations.
- c. & f. pH of water in the system, and Oxygen content in the system The "pH" and " oxygen content" of water is being determined in those
- systems, or portions of systems, identified as potentially susceptible to Single Phase Erosion / Corrosion.
This information will be utilized for determination of a trend, if any, d.
System temperature A rating system classifies the system temperatures and then an additional factor, flow condition (two phase,
- steam, saturated liquid or subcooled liquid),
is used to conservatively adjust the results.
The basis for the rating system is derived from Virginia Power's Surry Program.
4 Attachm:nt to ET' 87-0272
' September 10, 1987 i
Page 4 of 8.
l l-I e.
Fluid bulk velocity l
A rating.
system derived from Virginia Power and EPRI
~. recommendations uses fluid bulk velocity for single phase flow conditions.
For two phase and potential cavitation conditions, ratings are' assigned based on industry' design limits.
4..
Chronologically list and summarize the results of all inspections that have been performed,. which were specifically conducted for the purpose
,of identifying pipe wall thinning, whether or not pipe wall thinning was discovered, and any other inspections where pipe wall thinning was discovered even though that was not the purpose of that inspection.
a.
Briefly describe the inspection program and indicate whether it was specifically intended to measure wall thickness or whether wall thickness measurements were an incidental determination.
b.
Describe what piping was exanined and how ( e.g., describe the inspection-in str ument(s),
test method, reference thickness, locations examined, means for locating measurement point (s) in subsequent inspections).
c.
Report thickness measurement results and note those that were identified as unacceptable and why.
d.
Describe actions already taken or planned for piping that has been i
found to have a nonconforming wall thickness.
If you have l
performed a failure analysis, include the results of that an alysis.
Indicate whether the actions involve a repair or replacement, including any change of materials.
Table 1 is a summary o f.
inspections that have been performed specifically to measure pipe wall thicknesses.
These inspections were performed as a result of the Surry incident and prior experience of station personnel with Erosion / Corrosion in operating nuclear power plants.
Inspections, which are being performed at WCGS utilize ultrasonic thickness measuring devices and techniques specified in EPRI NP-3944 Minimum wall thickness for the Erosion / Corrosion measurements are specified as 87.5 percent nominal wall thickness values unless otherwise noted in design specifications.
Any measurements below minimum wall are doc umented and evaluated by engineering and repair / replacement decisions are then made by using criteria specified in item 2d.
Table 1 specifies repairs and replacements that have been performed to date and are planned during the next refueling outage.
[E J
Attachment to ET 87-0272 September 10, 1987 Page 5 of 8 l
Table 2 is a summary of inspections which identified areas where pipe wall thinning was discovered visually even thou6h that was not the purpose of the inspections.
1 1
5.
Describe any plans either for revising the present or for developing new j
or additional programs for monitoring. pipe wall thickness..
I WCGS proced ure ADM 08-212
" Erosion / Corrosion Monitoring Program" was j
d issued on July.17, 1987.
This procedure outlines administ,rative
- controls, defines responsibilities, and provides' step-by-step instructions for the implementation of the WCGS Erosion / Corrosion Program.
As previously noted, this program utilizes ultrasonic techniques, supplemented with visual' examinations.
Additionally, the feasibility of ' utilizing radiography as a supplemental examination technique is currently being investigated.
As this is a new program, there are no current plans for major revisions to the WCGS Erosion / Corrosion program. Based on engineering reviewc and results of pipe, wall measurements, the overall program could be reduced or expanded in the future.
l
A tachmsnt.to'ET 87-0272'-
. September 10, 1987
'Page'6-of 8-TABLE 1 Page.1 of 2 -
' NOMINAL EVALUATION MEASURED DATE WALL CRITERIA WALL SYSTEM LOCATION' INSPECTED THICKNESS (NOTE 1) THICKNESS REMARKS AC-Main Turbine ~
124-HBD-1" @ YS202 3/26/87 0.179 0.'157 0.120 Note 2
!(Drain. Piping) '
125-HBD-1" @ YS203 3/?6/87 0.179 0.157 0.150 Note 2 126-HBD-1" 6 YS205.'
bd/87 0.179 0.157-0.110 Note 2 127-HBD-1" @ YS206.
6/4/87 0.179 0.157 0.170 L128-HBD-1" @ YS207-6/5/87 0.179 0.157 0.135 Note 2 129-HBD-1" @ YS208 6/5/87 0.179 0.157 0.160 122-HBD-1" @ YS200 6/8/87 0.179 0.157 0.090-Note 2 123-HBD-1" @ YS201 6/8/87 0.179 0.157 0.125 Note 2-319-HBD-2",6 YS130 7/8/87 0.218 0.190 0.190 GE Piping 6 YS130 7/8/87 0.179 0.157 0.160 AF-Feedwater 274-HBD-1 1/2" @ F0-28 4/24/87 0.200 0.175
'0.195 Heater 321-HBD-1"
@ F0 4/24/87 0.179 0.157 0.172 Extraction Steam, 322-HBD-1 1/2" @ FO-52 4/24/87 0.200 0.175 0.190 Drains & Vents 325-HBD-1" 6 F0-44 4/24/87 0.179 0.157 0.183 326-HBD-1 1/2" @ F0-43 4/24/67 0.200 0.175 0.187 270-HBD-1 1/2" @ FO-37 4/24/87 0.200 0.175 0.192 266-HBD-1 1/2" @ FO-46 4/24/87 0.200 0.175 0.195 275-HBD-4"
@ F0-27 5/5/87 0 237 0.207 0.190 290-HBD-2"
@ FO-38 5/5/87 0.218 0.190 0.210 e
294-HBD-2"
@ F0-29 5/5/87 0.218 0.190 0.200 1 -
312-HBD-1 1/2" @ FO-32 5/5/87 0.200 0.175 0.190-271-HBD-4"
@ FO-36 5/5/87 0.237 0.207 0.215 303-HBD-1"
@ F0-51 6/30/87.
0.179 0.157
-0.173 304-HBD-1.1/2" @ FO-50 6/30/87- 0.200 0.175 0.201 284-HBD-1"
@ FO-48 7/1/87 0.179 0.157 0.172 285-HBD-2" 6 F0-47 7/1/87 0.218 0.190 0.210 213-GBD-1 1/2" @ EAE01B 7/8/87 0.200 0.175 0.190 EA-Service Water 020-HBD-6" G'V006 1/14/87 0.280 0.245 0.259 023-HBD-10" @ V011 1/14/87 0.365
- 0. 31 9 0.394 i
009-HBD-10" 6 V003 1/14/87 0.365 0.319 0.335 j
013-HBD-6" @ V005 1/14/87 0.280 0.245 0.241 Note 3 1
027-HBD-12" @ V013 1/14/87 0.375 0.328 0.520 043-HBD-12" @ V025 1/14/87 0.375 0.328 0.310 Note'3 l
046-HBD-12" @ V024 1/14/87 0.375 0.328 0.372 1
049-HBD-6" @ V027 1/14/87 0.280 0.245 0.276 051-HBD-6" @ V029 1/14/87 0.280 0.245 0.294 l
053-HBD-6" @ V031 1/14/87 0.280 0.245 0.274 055-HBD-6" @ V033 1/14/87 0.280 0.245 0.269 056-HBD-14" @ TV07 1/14/87 0.375 0.328 0.360 1
094-HBD-10" @ V015 1/14/87 0.365 0.319 0.360 r
i
' Attachment to ET 87-0272 l
September 10, 1987 Page 7 of 8 TABLE 1 Page 2 of 2 NOMINAL EVALUATION MEASURED DATE WALL CRITERIA WALL SYSTEM LOCATION INSPECTED THICKNESS (NOTE 1) THICKNESS REMARKS EF-Essential 080-HBC-24" @ V058 2/13/87 0.375 0.328 0.128 Note 4 Service Watet-075-HBC-8" P V053 2/18/87 0.322 0.281 0.307 076-HBC-24" e HV051 2/18/87 0.375 0.328 0.360 114-HBC-8" @ V080 2/18/87 0.322 0.281 0.304 129-HBC-24" 6 HV052 2/18/87 0.375 0.328 0.347 EG-Component 054-HBC-18" 6 EJY038 2/11/87 0.375 0.328 0.343 Water 027-HBC-18" @ EJV033 2/18/87 0.375 0.328 0.084 Note 4 028-HBC-12" O V201 2/19/87 0.375 0.328 0.439 018-HBC-12" @ V200 2/19/87 0.375 0.328 0.430 GN Containment 053-HBC-10" 6 V003 2/2/87 0.365 0.319 0.344 Heat Renoval 054-HBC-10" 6 V004 2/2/87 0.365 0.319 0.361 052-HBC-10" 6 V002 3/2/87 0.365 0.319 0.352 053-HBC-14" # V001 3/3/87 0.375 0.328 0.388 AD Condensate 051-GBD-24" @ HV028 6/12/87 0.688 0.602 0.683 039-GBD-24" 6 Header 12/12/87 0.688 0.602 0.720 1st Elbow from header 040-GBD-24" e Header 12/12/87 0.688 0.602 0.680 1st Elbow from Header 037-GBD-30" 6 Header 12/12/87 NA 0.515 0.595 Header pipe @
outlets 039-GBD-24" @ Header 12/12/87 0.688 0.602 0.650 At header exit 040-GBD-24" @ Header 12/12/87 0.688 0.602 0.750 At header exit 1
Evaluation Criteria = Nominal Vall Thickness X.875, or as specified in design doc um entation.
2.
Acceptable for interim operation - current plans are to replace during the second refueling outage.
3 Acceptable for interim operation - current plans are to replace with Type 316 Stainless Steel during the second refueling outage.
current plans are to 4.
Temporary repair utilizing external base metal repair replace with Type 316 Stainless Steel during the second refueling outage.
7
. o.. ;.-,
~Attachmtnt'to ET-87-0272'
- l. September 10, 1987-Page.8.of 8
. TABLE 2
-Page 1 of 1 DATE NOMINAL' SYSTEN LOCATION' INSPECTED WALL ~
NETHOD OF DETECTION-REMARKS
' F-Essential 090-HBC-10" 6 HV47
- 11/86-0.365 Visual Examination
. Note 1 Service' Water 125-HBC-10" 6 HV48 11/86 0.365
. Visual-Examination'
. Note 1:-
134-HBC-24" @ V090 11/86 0.375' Visual Examination'en Note:2 w
g.+
L,l 1.~
Repaired. utilizing internal base metal repair with a final' hard surfacing - current plans are to replace with ' type 316 stainless steel.during the.second ?refu~elins
~
outage.
-2.
Repaired utilizing internal base metal repair - current plans are to re' place - with-type 316 stainless steel during the second refueling outage.
I s-
e
('
g 1
.) O e'
O-.
et.
i 0
in :. '; (.
D
' It tD 8
m k Q
..i g..
O, W,--
o
, g 7-w
- <n, - -
r, p.
F s
.-