ML20070H342
| ML20070H342 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 07/14/1994 |
| From: | Mcmeekin T DUKE POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9407210222 | |
| Download: ML20070H342 (7) | |
Text
Il I
DukeIbwerCompany T C McMaw McGuire Nudear Gener2 ion Department ncePresident 12700Hagers Ferry Road (MGOHP)
(704)8754800 Huntencille, NC280784985 (704)8754809 Fat DUKEPOWER July 14, 1994 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Subjects McGuire Nuclear Station McGuire Nuclear Station, Docket Nos. 50-369, 50-370 Section XI, Inservice Inspection Hydrostatic Testing, Second Interval, Units 1 and 2 Relief Request 94-006 Doar Sir; Pursuant to 10 CFR 50.55a(g)(5)(Lii), I am submitting the attached relief request for NRC review and approval. This requent for relief from the requirements of Section XI of the ASME Code involves the hydrostatic testing of the class B piping within mechanical penetrations M372 and M373 during the second ten year interval. These penetrations are part of the glycol-water mixture supply and return lines for the Ice Condenser Refrigerant (NF) system.
ASME Code,Section XI, Table IWC-2500-1 specifies that a visual VT-2 examination be performed on pressure retaining components and piping under hydrostatic test to verify the overall integrity of the pressure retaining components and to identify any evidence of leakage. Technical Specification 4.6.1.2.d.4 defines the 10 CFR 50, Appendix J, Type C test as the proposed alternato examination method.- Appendix J states in part that the purpose of the tests are to assure that leakage through components penetrating primary containment does not exceed allowable rates, thus assuring the leak tight integrity of the primary containment. Penetrations M372 and M373, including the class B piping of this relief request, are subjected to the Appendix J, This Type C test in accordance with Technical Specification 4.6.1.2.d.4 Technical Specification requires that a zero indicated leakage rate be measured.in order for the test to be acceptable. Accordingly, the intent of the test and the examination method (verifying no leakage from the pressure 1
retaining components) is accomplished.
-Crrm e.,
9407210222 940714 PDR ADOCK 05^O0369
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U.S. Nuclear Regulatory Commission July 14, 1994 D
page 2
.i To facilitate the staff review of this item, please be advised that similar relief for the first interval was requested by a letter dated May 18, 1993 and supplemented by letter on May 25, 1993.
Based on the information submitted in those letters, the staff determined that the proposed relief could be granted pursuant to 10 CFR 50.55a (g)(6)(1) and that it was impractical to perform the type of visual examination required by the ASME Code; as to do so would initiate degradation of the ice condenser system.
Duke Power wcs informed of the Commission approval by letter dated June 3, 1993 (copy enclosed for your convenience).
Approval of this submittal is requested prior to August 15, 1994.
This date corresponds to the start of the Unit 1 End of Cycle Outage 9 Should there be any questions regarding this matter, please contact John M.
Washam at (704) 875-4181.
Very truly yours, fYAll s T.
C. McMeekin
U.S. Nuclear Regulatory Commission July 14, 1994 page 3 xc Mr.
S.D.
Ebneter Administrator, Region II U.S.
Nuclear Regulatory Commission 101 Marietta St.,
NW, Suite 2900 Atlanta, Ga.
30323 Mr. Robert E. Martin U.S.
Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D.C.
20555 Mr. George Maxwell Senior NRC Resident Inspector, McGuire McGuire Nuclear Station I
l 1
l l
j i
4 I
- i U.'S. Nuclear Regulatory Commission July 14, 1994 Page 4 bxc s - with attachments J.E. Snyder J.M. Washam R.D.
Klein (MGO1MM)
R.
Branch (MGo1MM)
C.B. Cheezem, Jr. (MGO2ND)
R.A. Johnasen (MG010P)
W.G. Goodman (EC07J)
G.J. Underwood (ECO5P)
M.F. Langel (MG01CP)
D.J.
Bumgardner (MGO1WC)
W.M. Sunlick (MG010P)
G.J. Holbrooks (MGOlCP)
J.O. Barbour (EC07J)
G.A.
Copp, III (EC050)
File: 801.01 ELL (EC050)
I i
DUKE POWER COMPANY.
1 McGUIRE NUCLEAR STATION REllEF REQUEST SERIAL NUMBER 94-006 Station:
McGuire Nuclear Station Unit (s):
1 and 2 i
Reference Code (s): 1986 Edition of Section XI for Unit 1 1989 Edition of Section XI for Unit 2 I.
Component for which exemption is requested:
a.
.Name and Identification Number:
Class B piping within Unit 1 Containment Penetrations M372 and M373.
Second ten year ISI inspection interval. McGuire Nuclear Station ISI Item Numbers C07.03.019 (system pressure test) and C07.040.017 (hydrostatic test).
Class B piping within Unit 2 Containment Penetrations M372 and M373.
Second ten year ISI inspection interval. McGuire Nuclear Station ISI Item Numbers C07.030.Oll (system pressure test) and C07.040.020 (hydrostatic test).
b.
Function:
The supply and return glycol-water mixture lines for the Ice Condenser Refrigeration System (McGuire system designation:
NF) c.
ASME Section XI Code Cases t
None d.
Construction Code and class (If Applicable):
ASME Section III, Class 2 e.
Valve category (If Applicable):
Not applicable f.
Attachments (list) or
References:
Copy of June 3, 1993. Notice of Approval for Relief Request 93-02.
a Page 1 of 3
1 DUKE POWER COMPANY McGUIRE NUCLEAR STATION RELIEF REQUEST
~
SERIAL NUMBER 94-006 II.
Reference Code Requirement from which relief is desired:
Unit la ASME Code Section XI, 1986 Edition, Subsection IWC, Subarticle 2500, Table IWC-2500-1, Examination Category C-H (All Pressure Retaining Components), Item Numbers C7.30 (system pressure testing of piping), and C7.40 (hydrostatic testing of piping).
Unit 2:
ASME Code Section XI, 1989 Edition, Subsection IWC, Subarticle 2500, Table IWC-2500-1, Examination Category C-H (All Pressure Retaining Components), Item Numbers C7.30 (system presoure testing of piping), and C7.40 (hydrostatic testing of piping).
III.
Basis for Requesting Relief:
The above listed Codes require that Class 2 piping for McGuire mechanical containment vessel penetration M372 and M373 be examined by performance of (1) a system pressure test each inspection period and (2) a hydrostatic test each interval.
These penetrations are part of the glycol-water mixture supply and return lines for the Unit 1 and Unit 2 Ice Condenser Refrigeration System (NF).
The lines are 4 inch insulated, carbon steel piping.
The examination method specified by the code is a VT-2 visual examination.
IWA-5242 delineates the requirements for performing a VT-2 visual examination of an insulated component.
IWA-5252 states that a VT-2 visual examination may be performed without removing insulation provided; 1) accessible and exposed surfaces and joints of insulation are examined; 2) vertical surfaces of insulation are examined at the lowest elevation; and 3) horizontal surfaces be examined at each insulation joint.
If the insulation surfaces are inaccessible for direct examination, then only surrounding areas need be examined.
The subject piping for penetrations M372 and M373 are encapsulated with ice and frost. This layer of ice and frost is due to the nature of the fluid (relatively lcw temperature glycol-water mixture) within the piping. The inspectors are unable to observe the areas of interest specified by the code for signs of leakage.
Therefore, a VT-2 visual examination can not be performed in accordance with the requirements specified within the ASME Section XI Code.
In order to perform the required VT-2 visual examination, the NF system would have to be shutdown for an extended period of time and the following actions completed:
remove the insulation, drain the glycol-water mixture, perform the examination, and reinstall the insulation.
Since these lines are in continuous service in order to maintain the ice basket inventory required for Unit operation, the NF system can not be shutdown and the glycol-water mixture drained.
Shutdown and draining of the NF system would result in the degradation of the safety related Ice condenser system due to a loss of ice inventory.
Furthermore, the recovery from NF system shutdown and draining would be a significant burden due to the need to re-weigh and reload ice baskets.
Page 2 0f 3
DUKE POWER COMPANY McGUIRE NUCLEAR STATION RELIEF REQUEST SERIAL NUMBER 94-006 IV.
Alternate Examination:
In lieu of the system pressure and hydrostatic tests, the Surveillance requirement of Technical Specification (TS) 4.6.1.2d.4 would be performed. This TS Surveillance specifies that the Appendix J, Type C test for penetrations M372 and M373 may be performed with glycol-water mixture as the pressurized i
fluid, provided that a zero indicated leakage rate is mea 9ured.
The Technical Specification requires this testing to be performed at least every 24 months.
The purpose of the Appendix J, Type C test (in accordance with TS 4.6.1.2d.4), the system pressure test and the hydrostatic test is to assure that no leakage exists in the system, thus verifying the integrity of the Class 2 piping associated with penetrations M372 and M373 in both Units 1 and 2.
Therefore, by performance of the Appendix J, Type C test and subsequent verification of no system leakage each outage, the alternative examination will provide a level of quality equal to the examination method specified in the governing code.
V.
Implementation Schedules The proposed alternative examination, will be performed during Unit 1 and 2 outages as required to meet the Technical Specification requirements during the second Inservice Inspection intervals.
Page 3 of 3
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2 UNITED STATES NUCLEAR REGULATORY COMMISSION c
p WASHINOfoN, D.C. 20555-0001
- j June 3, 1993 Docket Hos. 50-369 and 50-370 Mr. T. C. McHeskin Vice President, McGuire site Duke Power Company 12700 Hagers Ferry Road Huntersville, North Carolina 28078-8985
Dear Mr. McHeekin:
SUBJECT:
MCGUIRE NUCLEAR STATION - REQUEST FOR RELIEF FROM ASME SECTION XI INSERVICE INSPECTION HYDROSTATIC TESTING OF CLASS B PIPING WITHIN MECHANICAL PENETRATORS M372 AND M373 (TAC N0. M86405)
By letters dated May 18 and May 25, 1993, Duke Power Company submitted a relief request (Relief Request 93-02) for NRC's review and approval.
This i
request for relief involves a hydrostatic test of the Class 8 piping within mechanical penetrators M372 and M373 during the first ten-year interval.
Those penetrations are part of the glycol-water mixture supply and return lines for the ice condenser refrigerant system.
Based on the information submitted and determined that the licensee's, proposed relief request may be grantedt pursuant to 10 CFR 50.55a(g)(6)(1) as discussed in the enclosed Safety Evaluation.
The staff has concluded that it is impractical to perforta the type of visual examination required by the ASME Code; as to do so would initiate degradation of the ice condenser system. This relief is authorized by law and will not endanger life, aroperty, or the common defense and security and is otherwise in the pu)lic interest giving due consideration to the burden upon the licensee that could result if the ASME Code requirements were imposed upon the facility.
Sincerely, 4
David B. Matthews, Director Project Directorate II-3 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation
Enclosure:
Safety Evaluation j
cc w/ enclosure:
See next page FOR INFORMATION ONLY I
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UNITED STATES k'
NUCLEAR REGULATORY COMMISSION g%,* j WA&HINGTON, D.C. 2066(4 001 v
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION OF FIRST TEN-YEAR INSERVICE INSPECTION INTERVAL RE0 VEST FOR REllEF f_QB DUKE POWER COMPANY
.MCGUIRE NUCLEAR STATION. UNITS 1 AND 2 DOCKET NOS 50-369 AND 50-370 1.0 R(T_RODUCTION Technical Specification 4.0.5 for McGuire Nuclear Station Units 1 and 2 states that inservice inspection and testing of the American Society of Mechanical Engineers (ASME) Code Class 1, 2, and 3 components shall be-performed in accordance with Section XI of the ASME Boiler and Pressure Vessel Code and applicable Addenda as required by 10 CFR 50.55a(g), except where specific written relief has been granted by the Commission pursuant to 10 CFR 50.55a(g)(6)(i).
Section 10 CFR 50.55a(a)(3) states that alternatives to the requirements of paragraph (g) may be used, when authorized by the NRC, if (1) the proposed alternatives would provide an acceptable level of quality and safety, or (ii hardship or unusua) difficulties without a compensating increase in the levelcomplian l
of quality and safety.
Pursuant to 10 CFR 50.55a(g)(4), ASME Code Class 1, 2, and 3 components (including supports) shall meet the requirements, except the desigr. and access provisions and the preservice examination requirements., set forth in the ASME Code,Section XI, " Rules for Inservice Inspection of Nuclear Power plant components," to the extent practical within the limitations of design, geometry, and materials of construction of the components.
The regulations require that inservice examination of components and system pressure tests conducted during each ten-year interval comply with the requirements in the latest edition and addenda of Section XI of the ASME Code incorporated by reference in 10 CFR 50.55a(b) on the date twelve months prior to the start of the 120-month inspection interval, subject to t' a limitatidns and modifications listed therein.
The components (including supports) may meet the requirements set forth in subsequent editions and addenda of the ASME Code incorporated by reference in 10 CFR 50.55a(b) subject to the limitations and modifications listed therein, pursuant to 10 CFR 50.55a(g)(5), if the licensee determines that conformance with an examination requirement of Section XI of the ASME Code is not practical for its facility, information shall be submitted to the Commission in support of that determination and a request made for relief from the ASME Code requirement.
After evaluation of the determination, pursuant tc, 10 CFR 50.55a(g)(6)(1), the Commission may grant relief and may impose alternative requirements that are determined to be authorized by law, will not
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u-endanger life, property, or the comon defense and security, and are otherwise in the pubile interest, giving due consideration to the burden upon the licenses that could result if the requirements were imposed.
By letters dated May 18 and May 25, 1993, Duke Power Company (the licensee) submitted to the NRC a request for relief (Relief Request 93-02) from a pressure test requirement of Section XI of the ASME Code.
The licensee determined that to perform the specific requirement would be impractical during the First Ten-Year IS! interval for McGuire Units 1 and 2.
The staff has evaluated the licensee's request for relief from the Code requirement, and
)
its evaluation and conclusions are discussed in the following sections.
1 2.0 RE0VIREHENTS AND SUPPORTING INFORMATION Code Recuirements:
The component for which the licensee is requesting relief is the Class 8 piping within containment penetrations H372 and H373, Item Number C07.021.045.
This piping is the supply and return glycol-water mixture lines for the ice condenser refrigerant system and is designated to be ASME Section XI code Class 2.
The ASME Code Section XI requirement that the licensee has determined to be impractical is that contained in ASME Code Section XI,1980 Edition through Winter 1980 Addenda, Subsection IWC, Subarticle 2500, Table IWC-2500-1, Examination Category C-H (all pressure retaining components), Item Number C7.21.
The piping is required to be hydrostatically tested and visually examined.
Licensee's Basis for Re.questino Relief:
The examinat. ion specified by the code is a system hydrostatic test of the Class B piping for mechanical penetrations H372 and H373. These senetrations are part of the glycol-water mixture su) ply and return lines in tie Ice CondenserRefrigerationSystem(NF).
T1e lines are 4-inch carbon steel piping that is insulated.
The examination method specified by the code is a VT-2 visual exam.
IWA-5242 delineates the requirements for performing a VT-2 visual examination of an insulated component.
Briefly, IWA-5242 states that a VT-2 visual exam may be performed without removing insulation provided that:
- 1) accessible and exposed surfaces and joints of insulation are examined;
- 2) vertical surfaces of insulation are examined at the lowest elevation; and
- 3) horizontal surfaces be examined at each insulation joint.
If the insulated surfaces are inaccessible for direct examinations, then only surrounding areas need be examined.
The piping in question for penetrations M372 and H373 is encapsulated with ice and frost.
Due to this layer of ice and frost, a VT-2 visual examination cannot be performed in accordance with the requirements specified within the ASME Section XI Code.
The inspectors, during the examination, are not able to observe the appropriate areas for any signs of possible leakage.
This layer of ice and frost on the piping is believed to ba due to the nature of the fluid (glycol-water mixture) within the piping.
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FOR INFORMATION {
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As such, to perform the code required VT-2 visual examination, the insulation around the piping will need to be removed.
The NF system would have to be shut down for an extended period of time in order to:
remove the insulation, drain the glycol-water mixture, perform the examination, re-install the insulation and charge the system with the glycol-water mixture.- Since these lines are in service at all times to maintain the weight of the ice baskets, the NF system cannot be shut down and the glycol-water mixture drained.
Doing so would result in the degradation of the safety-related ice condenser system due to melting of the' ice.
Further, the recovery from such an incident would be a significant burden due to the need to re-weigh the ice baskets and the possible need to reload some.
Licensee's Procosed Alternative Examination:
The basic intent of a hydrostatic test is to verify the overall integrity of the pressure retaining componente of the system being examined.
The examination method specified by the ASME Code is a visual VT-2 exam. A VT-2 visual examination is performed in order to locate evidence of leakage or abnormal leakage from pressure retaining components.
The licensee proposes that in lieu of the system hydrostatic test, the Appendix J type C test of TS 4.6.1.2d.4) would be performed. As stated within Appendix J, one cf the purposes of the tests is to assure that leakage through components penetrating primary containment does not exceed allowable leakage rates, thus assuring leak-tight integrity of the primary containment.
For the particular penetrations in question (M372 and 373), the Appendix J type C test, performed in accordance with TS 4.6.1.2d.4), includes the class B piping of this relief recuest. The acceptance critoria specified by TS 4.6.1.2d.4) is that a zero incicated leakage rate is measured.
Accordingly, the intent of the test and the examination method (verifying no leakaga from the pressure retaining components) is accomplished.
3.0 STAFF EVALUATION AND CONCLUSION Pursuant to 10 CFR 50.55a(g)(5)(iii), the licensee determined that conformance with certain Code requirements are impractical for its facility and submitted supporting information. The staff has reviewed the licensee's submittal and agrees with the licensee that it is impractical to perform the Code required VT-2 visual examination.
The staff notes that in order to do the visual examination, it would require removal of the ice and frost in order to allow access and removal of the insulation around the pipe.
This would be followed by a draining of the glycol-water mixture, performing the Code required examination, re-installing the insulation, and charging the system with the glycol-water mixture.
The refrigerant system, although it is not a safety system, supports a safety system, the containment ice condenser system.
Shutting down the refrigerant system will initiate degradation of the safety related ico condenser system.
The licensee contends that the proposed alternative would provide an acceptable level of quality and safety since the hydrostatic test and the surveillance test are intended to determine that no leakage exists in the system, thus, indicating the integrity of the system.
The staff agrees with the licensee's contention that the proposed alternative would provide an acceptable level of quality and safety.
M / ( A '.J One 1t f *C C t._C A _ GA
. Pursuant to 10 CFR 50.55a(g)(6)(i), the staff concludes that the requirements of the Code are impractical and relief may be granted for Relief Request 93-02.
Such ralief is authorized by law and will not endanger life, property, or the common defense and security, and is otherwise in the public interest.
Relief has been granted giving due consideration to the burden upon the licensee that could result if the requirements were imposed on the facility.
Furthermore, the proposed alternative examinations should provide an acceptable level of quality and safety, and reasonable assurance that the structural integrity of the plant's systems, components, and supports will be maintained.
Principal Contributor:
Victor Nerses Dated:
June 3, 1993 FOR INFORMATION C)BJ L.'/
90/OO'd 60:11 E66T-EO-90