ML18038A754: Difference between revisions

From kanterella
Jump to navigation Jump to search
(Created page by program invented by StriderTol)
(StriderTol Bot change)
 
Line 16: Line 16:


=Text=
=Text=
{{#Wiki_filter:REGULATOR       FORMATION DISTRIBUTION S     EM (RIDS)
{{#Wiki_filter:REGULATOR FORMATION DISTRIBUTION S EM (RIDS)
ACCESSION NBR: 8709210273       DOC. DATE: 87/09/14   NOTARIZED: YES       DOCKET FACIL: 50-220 Nine Mile Point Nuclear Stationi Unit ii Niagara Poee 05000220 AUTH. NAME         AUTHOR AFFILIATION MANGANz C V.
ACCESSION NBR: 8709210273 DOC. DATE: 87/09/14 NOTARIZED:
          ~          Niagara Mohaek Power Corp.
YES DOCKET FACIL: 50-220 Nine Mile Point Nuclear Stationi Unit ii Niagara Poee 05000220 AUTH. NAME AUTHOR AFFILIATION MANGANz C ~ V.
RECIP. NAME         REC IP IENT AFFILIATION Document Cont'rol Branch (Document Control Desk)
Niagara Mohaek Power Corp.
RECIP. NAME REC IP IENT AFFILIATION Document Cont'rol Branch (Document Control Desk)


==SUBJECT:==
==SUBJECT:==
Forwards rosponse to info requested in NRC Bulletin 87-00ii "Thinning of Pipe Walls in Nuclear Power Plants. " Plant piping originally designed Cc fabricated per ASA B31. 1 Code for Pressure Piping 1955 Edition.
Forwards rosponse to info requested in NRC Bulletin 87-00ii "Thinning of Pipe Walls in Nuclear Power Plants. " Plant piping originally designed Cc fabricated per ASA B31.
DISTRIBUTION CODE: IE11D COPIES RECEIVED: LTR           ENCL     SIZE:
1 Code for Pressure Piping 1955 Edition.
DISTRIBUTION CODE:
IE11D COPIES RECEIVED: LTR ENCL SIZE:
TITLE: Bulletin Response (50 DKT)
TITLE: Bulletin Response (50 DKT)
NOTES:
NOTES:
RECIPIENT         COPIES          RECIPIENT        COPIES ID CODE/NAME       LTTR ENCL      ID CODE/NAME    LTTR ENCL PD1-1 LA               1    0    PD1-1 PD                  1 BENEDICT'               1    1    HAUGHEYi M          1    1 INTERNAL: AEOD/DOA                 1    1    AEOD/DSP            1    1 AEOD/DSP/TPAB           1    1    NRR/DEST/ADE        1     1 NRR/DEST/ADS            1    1    NRR/DEBT/MEB         1 NRR/DOEA/EAB                  1    NRR/DOEA/GCB         1    1 P/EPB                1    NRR/PMAS/ILRB       1    1 REG F LE      02      1    1    RES/DE/EIB FILE 01        1 . 1 EXTERNAL: LPDR                    1     1     NRC PDR              1     1 NSIC                    1     1 TOTAL NUMBER OF COPIES REQUIRED: LTTR         20   ENCL   19
RECIPIENT ID CODE/NAME PD1-1 LA BENEDICT' INTERNAL: AEOD/DOA AEOD/DSP/TPAB NRR/DEST/ADS NRR/DOEA/EAB P/EPB REG F LE 02 FILE 01 EXTERNAL:
LPDR NSIC COPIES LTTR ENCL 1
0 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 1
1 RECIPIENT ID CODE/NAME PD1-1 PD HAUGHEYi M AEOD/DSP NRR/DEST/ADE NRR/DEBT/MEB NRR/DOEA/GCB NRR/PMAS/ILRB RES/DE/EIB NRC PDR COPIES LTTR ENCL 1
1 1
1 1
1 1
1 1
1 1
1 1
1 TOTAL NUMBER OF COPIES REQUIRED:
LTTR 20 ENCL 19


O 7 NIAGARA N  V MOHAWK NIAGARAMOHAWKPOWER CORPORATION/301 PLAINFIELDROAD, SYRACUSE, N.Y. 13212/TELEPHONE (315) 474-1511 September   14, 1987 (NMPlL 1087)
O N 7 NIAGARA V MOHAWK NIAGARAMOHAWKPOWER CORPORATION/301 PLAINFIELDROAD, SYRACUSE, N.Y. 13212/TELEPHONE (315) 474-1511 September 14, 1987 (NMPlL 1087)
U.S. Nuclear Regulatory Commission Attn:     Document Control Desk Washington, D.C. 20555 Re: Nine Mile Point Unit       1 Docket No. 50-220 DPR-63 Gentlemen:
U.S. Nuclear Regulatory Commission Attn:
Please find attached the information on Nine Mile Point Unit               1 as requested in "NRC Bulletin No. 87-01: Thinning of Pipe Walls In Nuclear Power Plants."
Document Control Desk Washington, D.C.
Very truly yours, NIAGARA MOHAWK'POWER CORPORATION C. V. Mangan Senior Vice President GAG/pns 3690G/1 Attachment cc:   Regional Administrator, Region I Hr. R: A. Capra, Director Hr. R. A. Benedict, Project Manager Hr. W. A. Cook, Resident Inspector 8709210273 870914 PDR 6
20555 Re:
ADOCK 05000220 gg Il PDR I)   I
Nine Mile Point Unit 1
Docket No. 50-220 DPR-63 Gentlemen:
Please find attached the information on Nine Mile Point Unit 1
as requested in "NRC Bulletin No. 87-01:
Thinning of Pipe Walls In Nuclear Power Plants."
Very truly yours, NIAGARA MOHAWK'POWER CORPORATION C. V. Mangan Senior Vice President GAG/pns 3690G/1 Attachment cc:
Regional Administrator, Region I Hr.
R: A. Capra, Director Hr.
R. A. Benedict, Project Manager Hr.
W. A. Cook, Resident Inspector 8709210273 870914 PDR ADOCK 05000220 6
PDR gg Il I) I


UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter     of                                   )
UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of
l Niagara Mohawk Power Corporation                         ]           Docket No. 50-220
)
                                                        )
l Niagara Mohawk Power Corporation
(Nine Mile Point Unit               1 )                 ]
]
AFFIDAVIT C. V. Man an                   , being duly sworn, states that he is Senior Vice President of Niagara Mohawk Power Corporation; that he is authorized on the part of said Corporation to sign and file with the Nuclear Regulatory Commission the documents attached hereto; and that all such documents are true and correct to the best of his knowledge, information and belief.
)
Subscribed and sworn to before me,                         a Notary Public in and for the State of New York and County         of                                         , this     ~4         day of                               ,   1987.
(Nine Mile Point Unit 1 )
N ary Public in and for County,       New York My Commission expires:
]
MARY FRATESCHI ot:,'ovr Yolky ttotory Puottt In tho Stoto i n Onondn"n County lto, 4797/+)
Docket No.
                ! r'n Quito.lo tn Cotntntootun ill'jtios   940i t9
50-220 AFFIDAVIT C.
V.
Man an
, being duly sworn, states that he is Senior Vice President of Niagara Mohawk Power Corporation; that he is authorized on the part of said Corporation to sign and file with the Nuclear Regulatory Commission the documents attached hereto; and that all such documents are true and correct to the best of his knowledge, information and belief.
Subscribed and sworn to before me, a Notary Public in and for the State of New York and County of
, this
~4 day of
, 1987.
N ary Public in and for
: County, New York My Commission expires:
MARY FRATESCHI ttotory Puottt In tho Stoto ot:,'ovr Yolky Quito.lo i n
! r'n Onondn"n County lto, 4797/+)
tn Cotntntootun ill'jtios 940i t9


0 I
0 I ~
    ~


4     NINE MILE POINT UNIT ONE
4 NINE MILE POINT UNIT ONE 1.
: 1. Identify the codes or standards to which the piping       was designed   and fabricated.
Identify the codes or standards to which the piping was designed and fabricated.
The Nine   Mile Point Unit One plant piping was originally designed and fabricated in accordance with ASA B31.1 Code for Pressure Piping - 1955 Edition. All piping from the reactor vessel connections to the external isolation valves was designed and fabricated in accordance with ASA B31.1 1955 Edition,,and ASME Boiler and Pressure Vessel Code Section I - 1962 Edition and Articles N460 to N469 of ASME Section III 1965 Edition.
The Nine Mile Point Unit One plant piping was originally designed and fabricated in accordance with ASA B31.1 Code for Pressure Piping - 1955 Edition.
Subsequent piping modifications and additions were designed and fabricated in accordance with then applicable editions of ASME Boiler         and Pressure Vessel Code, Sections III, XI, and ANSI B31.1 Power Piping, including the latest addenda.
All piping from the reactor vessel connections to the external isolation valves was designed and fabricated in accordance with ASA B31.1 1955 Edition,,and ASME Boiler and Pressure Vessel Code Section I - 1962 Edition and Articles N460 to N469 of ASME Section III 1965 Edition.
: 2. Describe the scope and extent of your programs for ensuring that pipe wall thicknesses are not reduced below the minimum allowable thickness.
Subsequent piping modifications and additions were designed and fabricated in accordance with then applicable editions of ASME Boiler and Pressure Vessel
: Code, Sections III, XI, and ANSI B31.1 Power Piping, including the latest addenda.
2.
Describe the scope and extent of your programs for ensuring that pipe wall thicknesses are not reduced below the minimum allowable thickness.
Include in the description the criteria that you have established.
Include in the description the criteria that you have established.
The Nine   Mile Point Unit 1 Erosion-Corrosion Review Program has been expanded   in scope to include our recently developed single-phase Erosion-Corrosion Review Program. This is an addition to our existing ongoing Two-Phase Flow Erosion-Corrosion Review Program established in 1981. The program's purpose is to review the material deterioration of piping systems transporting single and two-phase fluids.
The Nine Mile Point Unit 1 Erosion-Corrosion Review Program has been expanded in scope to include our recently developed single-phase Erosion-Corrosion Review Program.
The program   reviews include piping system designs,     as-built installations, testing     and operating history.
This is an addition to our existing ongoing Two-Phase Flow Erosion-Corrosion Review Program established in 1981.
The NUMARC Summary Report on Piping Erosion-Corrosion dated June         ll, 1987 and other creditable publications (e.g. EPRI-CHECK, ANSI/ASME CODES, UTILITY REPORTS, UNIVERSITY RESEARCH REPORTS) are used as guidance documents   in establishing sample selection, selection points, sample expansion, inspection techniques,     measurement frequency and repair replacement decisions.
The program's purpose is to review the material deterioration of piping systems transporting single and two-phase fluids.
* The guidance criteria   being used .are:
The program reviews include piping system designs, as-built installations, testing and operating history.
(a)   Measurement   Locations The six attributes listed in Action Request Number 3 plus the additional attribute of steam quality for two-phase flow are considered in selecting review locations.
The NUMARC Summary Report on Piping Erosion-Corrosion dated June ll, 1987 and other creditable publications (e.g.
(b)   Ins ection Fre uenc Inspection frequency is dependent         upon material conditions, erosion-corrosion rates established       and estimated meantime to minimum wall condition.
EPRI-CHECK, ANSI/ASME CODES, UTILITY REPORTS, UNIVERSITY RESEARCH REPORTS) are used as guidance documents in establishing sample selection, selection points, sample expansion, inspection techniques, measurement frequency and repair replacement decisions.
(c)   Measurement   Methods Measurement Methods are dependent upon the established   location and field conditions.   '.T. or U.T.
The guidance criteria being used.are:
(internal/external) may be employed. where initial review is planned. UT (external) may be employed where evidence or potential evidence of erosion-corrosion     is present. Disassembly and actual measurements   of wall thickness is also   an available option.
(a)
Measurement Locations The six attributes listed in Action Request Number 3 plus the additional attribute of steam quality for two-phase flow are considered in selecting review locations.
(b)
Ins ection Fre uenc Inspection frequency is dependent upon material conditions, erosion-corrosion rates established and estimated meantime to minimum wall condition.
(c)
Measurement Methods Measurement Methods are dependent upon the established location and field conditions. '.T. or U.T.
(internal/external) may be employed. where initial review is planned.
UT (external) may be employed where evidence or potential evidence of erosion-corrosion is present.
Disassembly and actual measurements of wall thickness is also an available option.
(9327I)
(9327I)


(d)     Re air/Re la     nt Codes/standards   complian     stablishes the action taken. Our policy is to repair or replace piping which is below the Code/Standard     minimum wall thickness allowable.
(d)
: 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.=
Re air/Re la nt Codes/standards complian stablishes the action taken.
Factors 3(a) through 3(f). stated in the Commission action item         list are included in our program.
Our policy is to repair or replace piping which is below the Code/Standard minimum wall thickness allowable.
                                                      /
3.
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.
For liquid phase
4a. 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.
: systems, state specifically whether the following factors have been considered in establishing your criteria for selecting points at which to monitor piping thickness.=
During 1979, 1981, 1984 and 1986 refueling outages, erosion-corrosion inspections were instituted to monitor the status of potentially susceptible piping systems for material deterioration. Their purpose was to identify pipe wall thinning caused by two-phase flow erosion and corrosion. In 1981 an erosion-corrosion review program for turbine cycle piping was developed by SNG Consulting Engineers and implemented by Niagara Mohawk Inservice Inspection (ISI) personnel.         This program measures wall thickness for the wear effects of erosion-corrosion on the cold reheat, hot reheat and wet drain piping installed in Nine Mile Point Unit   One.
Factors 3(a) through 3(f). stated in the Commission action item list are included in our program.
These     inspections are on record   as part of the Nine Mile Point Unit   One Inservice Inspection Program.
4
4b. Describe what piping was examined and how; (e.g. describe the inspection instruments, test method, reference thickness, locations examined, means for locating measurement points in subsequent inspections).
~
The   following Nine Mile Point Unit One locations       were examined during, the 1981   turbine cycle erosion-corrosion program:
/
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.
4a.
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.
During 1979,
: 1981, 1984 and 1986 refueling outages, erosion-corrosion inspections were instituted to monitor the status of potentially susceptible piping systems for material deterioration.
Their purpose was to identify pipe wall thinning caused by two-phase flow erosion and corrosion.
In 1981 an erosion-corrosion review program for turbine cycle piping was developed by SNG Consulting Engineers and implemented by Niagara Mohawk Inservice Inspection (ISI) personnel.
This program measures wall thickness for the wear effects of erosion-corrosion on the cold reheat, hot reheat and wet drain piping installed in Nine Mile Point Unit One.
These inspections are on record as part of the Nine Mile Point Unit One Inservice Inspection Program.
4b.
Describe what piping was examined and how; (e.g. describe the inspection instruments, test method, reference thickness, locations examined, means for locating measurement points in subsequent inspections).
The following Nine Mile Point Unit One locations were examined during, the 1981 turbine cycle erosion-corrosion program:
Extraction steam piping to all feedwater heaters (1st through 5th).
Extraction steam piping to all feedwater heaters (1st through 5th).
Extraction steam line drains.
Extraction steam line drains.
Turbine Building     Misc. steam piping, reheaters,   air ejector, regulator and.turbine bypass.
Turbine Building Misc.
Cold reheat steam to reheaters     from high pressure   turbine to moisture separators.
steam piping, reheaters, air ejector, regulator and.turbine bypass.
Cold reheat steam to reheaters from high pressure turbine to moisture separators.
Hetdrain lines.
Hetdrain lines.
(9327I)
(9327I)


During the Nine Hi     Point Unit One 1984 and 1986 r . @cling outages, portions of the following systems were examined for pipe wall thinning:
During the Nine Hi Point Unit One 1984 and 1986 r
Main Steam   Injection Lines Turbine Building Wet Drains Northwest and Northeast Moisture Separators Hain Condenser Hater Boxes Torus Feedwater Drain Piping to Condensers Hain Steam Pipe Bends Reheater Drain Piping Thickness examinations for the above listed locations were performed using ultrasonic pulse echo dual element transducer techniques applied to the outside surfaces (O.D.) of the pipe, fittings,"and'omponents.       Each pipe, fitting, or component was ultrasonically examined in a "band" the circumference in at least three locations. The test equipment360'round used consisted of two search units (i.e. 2.25 HHZ, .375" diameter, duel element and 5.0 MHZ, .250" or .375" diameter. Ultrasonic examination personnel were certified in accordance with ASNT, SNT-TC-lA, 1980 Editions The reference 'thickness used to compare against measured thickness is the nominal pipe wall thickness.
. @cling outages, portions of the following systems were examined for pipe wall thinning:
Subsequent inspections will be performed based on the results of benchmark or initial inspections.       The locations and timing of subsequent inspections would be based on the predicted erosion-corrosion rates, calculated using the benchmark inspection data and related acceptance criteria.
Main Steam Injection Lines Turbine Building Wet Drains Northwest and Northeast Moisture Separators Hain Condenser Hater Boxes Torus Feedwater Drain Piping to Condensers Hain Steam Pipe Bends Reheater Drain Piping Thickness examinations for the above listed locations were performed using ultrasonic pulse echo dual element transducer techniques applied to the outside surfaces (O.D.) of the pipe, fittings,"and'omponents.
4c. Report thickness measurement     results and note those that were identified as unacceptable   and why.
Each pipe, fitting, or component was ultrasonically examined in a "band" 360'round the circumference in at least three locations.
The 1981   Nine Mile Point   Unit One pipe wall inspections yielded acceptable   UT thickness measurements. All of the approximate two hundred locations examined had measurements which exceeded the calculated minimum wall code requirements of the system. The most susceptible locations of wall thinning indicated measurements between 10/.-12% below nominal wall thickness. These measurements are acceptable per code allowable mill tolerances of + 12-1/2%%d of nominal wall thickness. One measurement taken on a 1.0" extraction steam piping section to the 4th feedwater was 15/
The test equipment used consisted of two search units (i.e. 2.25 HHZ,.375" diameter, duel element and 5.0 MHZ,.250" or.375" diameter.
below nominal wall thickness.       The code calculated minimum wall thickness for the 10" section is 0.117".
Ultrasonic examination personnel were certified in accordance with ASNT, SNT-TC-lA, 1980 Editions The reference
    .The thickness measurements     performed during the 1984 and 1986 outages,         as a part of the Inservice Inspection Program, exceeded the minimum wall requirements for the systems involved. Some discrepancies existed between the 1984 and 1986 data at various locations and the results were considered to be inconclusive. These areas will be re-examined during 1988 outage.
'thickness used to compare against measured thickness is the nominal pipe wall thickness.
                                                                                        'he The results of   1984 and 1986 inspections are given in the Nine Mile Point Unit One Inservice Inspection Reports.
Subsequent inspections will be performed based on the results of benchmark or initial inspections.
The locations and timing of subsequent inspections would be based on the predicted erosion-corrosion
: rates, calculated using the benchmark inspection data and related acceptance criteria.
4c.
Report thickness measurement results and note those that were identified as unacceptable and why.
The 1981 Nine Mile Point Unit One pipe wall inspections yielded acceptable UT thickness measurements.
All of the approximate two hundred locations examined had measurements which exceeded the calculated minimum wall code requirements of the system.
The most susceptible locations of wall thinning indicated measurements between 10/.-12% below nominal wall thickness.
These measurements are acceptable per code allowable mill tolerances of +
12-1/2%%d of nominal wall thickness.
One measurement taken on a
1.0" extraction steam piping section to the 4th feedwater was 15/
below nominal wall thickness.
The code calculated minimum wall thickness for the 10" section is 0.117".
.The thickness measurements performed during the 1984 and 1986 outages, as a part of the Inservice Inspection
: Program, exceeded the minimum wall requirements for the systems involved.
Some discrepancies existed between the 1984 and 1986 data at various locations and the results were considered to be inconclusive.
These areas will be re-examined during
'he 1988 outage.
The results of 1984 and 1986 inspections are given in the Nine Mile Point Unit One Inservice Inspection Reports.
(9327I)
(9327I)


4d. Describe actions to have  a lady     taken or planned for pipi nonconfo~ng wall thickness.
4d.
hat have been found Inspections of the wet steam drains in 1981 revealed some wall thinning at the two-inch elbows of the four (4) turbine stop valve lower seat drain lines. The action taken was to replace the piping and elbows.
Describe actions lady taken or planned for pipi hat have been found to have a nonconfo~ng wall thickness.
Inspections of the wet steam drains in 1981 revealed some wall thinning at the two-inch elbows of the four (4) turbine stop valve lower seat drain lines.
The action taken was to replace the piping and elbows.
Monitoring of these installed materials has not produced any indication of material deterioration.
Monitoring of these installed materials has not produced any indication of material deterioration.
: 5. Describe any plans either for reviewing the present or for developing   new or additional programs for monitoring pipe wall thickness.
5.
The, single-phase erosion-corrosion part of the Nine Mile Point Unit One Erosion-Corrosion Review Program has recently been developed and is currently being implemented. The first single-phase, plant piping examinations are scheduled for 1988 refueling outage. Future refueling outages will include single and two-phase carbon steel piping wall thickness measurements. Additional plans will be dependent upon the results of the data obtained during the 1988 refueling outage.
Describe any plans either for reviewing the present or for developing new or additional programs for monitoring pipe wall thickness.
The, single-phase erosion-corrosion part of the Nine Mile Point Unit One Erosion-Corrosion Review Program has recently been developed and is currently being implemented.
The first single-phase, plant piping examinations are scheduled for 1988 refueling outage. Future refueling outages will include single and two-phase carbon steel piping wall thickness measurements.
Additional plans will be dependent upon the results of the data obtained during the 1988 refueling outage.
(9327I)}}
(9327I)}}

Latest revision as of 00:59, 7 January 2025

Forwards Response to Info Requested in NRC Bulletin 87-001, Thinning of Pipe Walls in Nuclear Power Plants. Plant Piping Originally Designed & Fabricated Per Asa B31.1 Code for Pressure Piping - 1955 Edition
ML18038A754
Person / Time
Site: Nine Mile Point Constellation icon.png
Issue date: 09/14/1987
From: Mangan C
NIAGARA MOHAWK POWER CORP.
To:
NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
(NMP1L-1087), IEB-87-001, IEB-87-1, NUDOCS 8709210273
Download: ML18038A754 (14)
v • d • e


Text

REGULATOR FORMATION DISTRIBUTION S EM (RIDS)

ACCESSION NBR: 8709210273 DOC. DATE: 87/09/14 NOTARIZED:

YES DOCKET FACIL: 50-220 Nine Mile Point Nuclear Stationi Unit ii Niagara Poee 05000220 AUTH. NAME AUTHOR AFFILIATION MANGANz C ~ V.

Niagara Mohaek Power Corp.

RECIP. NAME REC IP IENT AFFILIATION Document Cont'rol Branch (Document Control Desk)

SUBJECT:

Forwards rosponse to info requested in NRC Bulletin 87-00ii "Thinning of Pipe Walls in Nuclear Power Plants. " Plant piping originally designed Cc fabricated per ASA B31.

1 Code for Pressure Piping 1955 Edition.

DISTRIBUTION CODE:

IE11D COPIES RECEIVED: LTR ENCL SIZE:

TITLE: Bulletin Response (50 DKT)

NOTES:

RECIPIENT ID CODE/NAME PD1-1 LA BENEDICT' INTERNAL: AEOD/DOA AEOD/DSP/TPAB NRR/DEST/ADS NRR/DOEA/EAB P/EPB REG F LE 02 FILE 01 EXTERNAL:

LPDR NSIC COPIES LTTR ENCL 1

0 1

1 1

1 1

1 1

1 1

1 1

1 1

1 1

1 1

1 RECIPIENT ID CODE/NAME PD1-1 PD HAUGHEYi M AEOD/DSP NRR/DEST/ADE NRR/DEBT/MEB NRR/DOEA/GCB NRR/PMAS/ILRB RES/DE/EIB NRC PDR COPIES LTTR ENCL 1

1 1

1 1

1 1

1 1

1 1

1 1

1 TOTAL NUMBER OF COPIES REQUIRED:

LTTR 20 ENCL 19

O N 7 NIAGARA V MOHAWK NIAGARAMOHAWKPOWER CORPORATION/301 PLAINFIELDROAD, SYRACUSE, N.Y. 13212/TELEPHONE (315) 474-1511 September 14, 1987 (NMPlL 1087)

U.S. Nuclear Regulatory Commission Attn:

Document Control Desk Washington, D.C.

20555 Re:

Nine Mile Point Unit 1

Docket No. 50-220 DPR-63 Gentlemen:

Please find attached the information on Nine Mile Point Unit 1

as requested in "NRC Bulletin No. 87-01:

Thinning of Pipe Walls In Nuclear Power Plants."

Very truly yours, NIAGARA MOHAWK'POWER CORPORATION C. V. Mangan Senior Vice President GAG/pns 3690G/1 Attachment cc:

Regional Administrator, Region I Hr.

R: A. Capra, Director Hr.

R. A. Benedict, Project Manager Hr.

W. A. Cook, Resident Inspector 8709210273 870914 PDR ADOCK 05000220 6

PDR gg Il I) I

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION In the Matter of

)

l Niagara Mohawk Power Corporation

]

)

(Nine Mile Point Unit 1 )

]

Docket No.

50-220 AFFIDAVIT C.

V.

Man an

, being duly sworn, states that he is Senior Vice President of Niagara Mohawk Power Corporation; that he is authorized on the part of said Corporation to sign and file with the Nuclear Regulatory Commission the documents attached hereto; and that all such documents are true and correct to the best of his knowledge, information and belief.

Subscribed and sworn to before me, a Notary Public in and for the State of New York and County of

, this

~4 day of

, 1987.

N ary Public in and for

County, New York My Commission expires:

MARY FRATESCHI ttotory Puottt In tho Stoto ot:,'ovr Yolky Quito.lo i n

! r'n Onondn"n County lto, 4797/+)

tn Cotntntootun ill'jtios 940i t9

0 I ~

4 NINE MILE POINT UNIT ONE 1.

Identify the codes or standards to which the piping was designed and fabricated.

The Nine Mile Point Unit One plant piping was originally designed and fabricated in accordance with ASA B31.1 Code for Pressure Piping - 1955 Edition.

All piping from the reactor vessel connections to the external isolation valves was designed and fabricated in accordance with ASA B31.1 1955 Edition,,and ASME Boiler and Pressure Vessel Code Section I - 1962 Edition and Articles N460 to N469 of ASME Section III 1965 Edition.

Subsequent piping modifications and additions were designed and fabricated in accordance with then applicable editions of ASME Boiler and Pressure Vessel

Code, Sections III, XI, and ANSI B31.1 Power Piping, including the latest addenda.

2.

Describe the scope and extent of your programs for ensuring that pipe wall thicknesses are not reduced below the minimum allowable thickness.

Include in the description the criteria that you have established.

The Nine Mile Point Unit 1 Erosion-Corrosion Review Program has been expanded in scope to include our recently developed single-phase Erosion-Corrosion Review Program.

This is an addition to our existing ongoing Two-Phase Flow Erosion-Corrosion Review Program established in 1981.

The program's purpose is to review the material deterioration of piping systems transporting single and two-phase fluids.

The program reviews include piping system designs, as-built installations, testing and operating history.

The NUMARC Summary Report on Piping Erosion-Corrosion dated June ll, 1987 and other creditable publications (e.g.

EPRI-CHECK, ANSI/ASME CODES, UTILITY REPORTS, UNIVERSITY RESEARCH REPORTS) are used as guidance documents in establishing sample selection, selection points, sample expansion, inspection techniques, measurement frequency and repair replacement decisions.

The guidance criteria being used.are:

(a)

Measurement Locations The six attributes listed in Action Request Number 3 plus the additional attribute of steam quality for two-phase flow are considered in selecting review locations.

(b)

Ins ection Fre uenc Inspection frequency is dependent upon material conditions, erosion-corrosion rates established and estimated meantime to minimum wall condition.

(c)

Measurement Methods Measurement Methods are dependent upon the established location and field conditions. '.T. or U.T.

(internal/external) may be employed. where initial review is planned.

UT (external) may be employed where evidence or potential evidence of erosion-corrosion is present.

Disassembly and actual measurements of wall thickness is also an available option.

(9327I)

(d)

Re air/Re la nt Codes/standards complian stablishes the action taken.

Our policy is to repair or replace piping which is below the Code/Standard minimum wall thickness allowable.

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.=

Factors 3(a) through 3(f). stated in the Commission action item list are included in our program.

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.

4a.

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.

During 1979,

1981, 1984 and 1986 refueling outages, erosion-corrosion inspections were instituted to monitor the status of potentially susceptible piping systems for material deterioration.

Their purpose was to identify pipe wall thinning caused by two-phase flow erosion and corrosion.

In 1981 an erosion-corrosion review program for turbine cycle piping was developed by SNG Consulting Engineers and implemented by Niagara Mohawk Inservice Inspection (ISI) personnel.

This program measures wall thickness for the wear effects of erosion-corrosion on the cold reheat, hot reheat and wet drain piping installed in Nine Mile Point Unit One.

These inspections are on record as part of the Nine Mile Point Unit One Inservice Inspection Program.

4b.

Describe what piping was examined and how; (e.g. describe the inspection instruments, test method, reference thickness, locations examined, means for locating measurement points in subsequent inspections).

The following Nine Mile Point Unit One locations were examined during, the 1981 turbine cycle erosion-corrosion program:

Extraction steam piping to all feedwater heaters (1st through 5th).

Extraction steam line drains.

Turbine Building Misc.

steam piping, reheaters, air ejector, regulator and.turbine bypass.

Cold reheat steam to reheaters from high pressure turbine to moisture separators.

Hetdrain lines.

(9327I)

During the Nine Hi Point Unit One 1984 and 1986 r

. @cling outages, portions of the following systems were examined for pipe wall thinning:

Main Steam Injection Lines Turbine Building Wet Drains Northwest and Northeast Moisture Separators Hain Condenser Hater Boxes Torus Feedwater Drain Piping to Condensers Hain Steam Pipe Bends Reheater Drain Piping Thickness examinations for the above listed locations were performed using ultrasonic pulse echo dual element transducer techniques applied to the outside surfaces (O.D.) of the pipe, fittings,"and'omponents.

Each pipe, fitting, or component was ultrasonically examined in a "band" 360'round the circumference in at least three locations.

The test equipment used consisted of two search units (i.e. 2.25 HHZ,.375" diameter, duel element and 5.0 MHZ,.250" or.375" diameter.

Ultrasonic examination personnel were certified in accordance with ASNT, SNT-TC-lA, 1980 Editions The reference

'thickness used to compare against measured thickness is the nominal pipe wall thickness.

Subsequent inspections will be performed based on the results of benchmark or initial inspections.

The locations and timing of subsequent inspections would be based on the predicted erosion-corrosion

rates, calculated using the benchmark inspection data and related acceptance criteria.

4c.

Report thickness measurement results and note those that were identified as unacceptable and why.

The 1981 Nine Mile Point Unit One pipe wall inspections yielded acceptable UT thickness measurements.

All of the approximate two hundred locations examined had measurements which exceeded the calculated minimum wall code requirements of the system.

The most susceptible locations of wall thinning indicated measurements between 10/.-12% below nominal wall thickness.

These measurements are acceptable per code allowable mill tolerances of +

12-1/2%%d of nominal wall thickness.

One measurement taken on a

1.0" extraction steam piping section to the 4th feedwater was 15/

below nominal wall thickness.

The code calculated minimum wall thickness for the 10" section is 0.117".

.The thickness measurements performed during the 1984 and 1986 outages, as a part of the Inservice Inspection

Program, exceeded the minimum wall requirements for the systems involved.

Some discrepancies existed between the 1984 and 1986 data at various locations and the results were considered to be inconclusive.

These areas will be re-examined during

'he 1988 outage.

The results of 1984 and 1986 inspections are given in the Nine Mile Point Unit One Inservice Inspection Reports.

(9327I)

4d.

Describe actions lady taken or planned for pipi hat have been found to have a nonconfo~ng wall thickness.

Inspections of the wet steam drains in 1981 revealed some wall thinning at the two-inch elbows of the four (4) turbine stop valve lower seat drain lines.

The action taken was to replace the piping and elbows.

Monitoring of these installed materials has not produced any indication of material deterioration.

5.

Describe any plans either for reviewing the present or for developing new or additional programs for monitoring pipe wall thickness.

The, single-phase erosion-corrosion part of the Nine Mile Point Unit One Erosion-Corrosion Review Program has recently been developed and is currently being implemented.

The first single-phase, plant piping examinations are scheduled for 1988 refueling outage. Future refueling outages will include single and two-phase carbon steel piping wall thickness measurements.

Additional plans will be dependent upon the results of the data obtained during the 1988 refueling outage.

(9327I)

Retrieved from "https://kanterella.com/w/index.php?title=ML18038A754&oldid=5029374"