Text

Inservice Inspection (ISI) Program Relief Request 4ISI-05
	ML16054A797
Person / Time
Site:	Columbia
Issue date:	02/17/2016
From:	Javorik A; Energy Northwest
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	GO2-16-012
	Download: ML16054A797 (8)
	v • d • e

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' **;j* *, ENERGY

i NORTHWEST Alex L. Javorik Vice President, Engineering P.O. Box 968, Mail Drop PE20 Richiand, WA 99352-0968 Ph. 509-377-8555 F. 509-377-4317 aljavorik@ energy-northwest.com FE8 1 7' 20]18 10 CFR 50.55a G02-1 6-012 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Subject:

COLUMBIA GENERATING STATION, DOCKET NO. 50-397; INSERVICE INSPECTION (ISI) PROGRAM RELIEF REQUEST 41S1-05

Reference:

Code Case N-805, "Alternative to Class 1 Extended Boundary End of Interval or Class 2 System Leakage Testing of the Reactor Vessel Head Flange 0-Ring Leak-Detection System," approved by the American Society of Mechanical Engineers (ASME) on February 25, 2011...

Dear Sir or Madam:

Pursuant to 10 CFR 50.55a(z)(2), Energy Northwest hereby requests NRC approval of the following relief request for the fourth ten-year inservice inspection (181) program interval at Columbia Generating Station ending December 12, 2025. Energy Northwest has determined that compliance with certain inspection requirements of ASME Section XI would result in unnecessary hardship or unusual difficulty without a compensating increase in the level of quality and safety. The details of the 10 CFR 50.55a request are enclosed as.

Energy Northwest requests approval within one year of the date of the submittal to accommodate application of the request during the next refueling outage.

There are no new commitments made in this submittal. If you have any questions or require additional information, please contact Ms. L.L: Williams at 509-377-3148.

Executed this /7t' day, of.L/"LL 2016.

Respectfully, Vice President, Engineering

Attachment:

(1)10 CFR 50.55a Relief Request Number 4,S,-05

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GO2-1 6-012 Page 2 cc:

NRC RIV Regional Administrator NRC NRR Project Manager NRC Sr. Resident Inspector - 9880 CD Sonoda - BPA - 1399 (email)

WA Horin - Winston & Strawn

GO2-1 6-012 Page 1 of 6 10 CFR 50.55a Relief Request Number 41SI-05 Alternative Test Method for RPV Leak Detection Line Proposed Alternative In Accordance with 10 CFR 50.55a(z)(2)

Hardship or Unusual Difficulty without Compensating Increase in Level of Quality or Safety

1. ASME Code Component(s) Affected

==

Description:==

ASME Code Class:

Examination Category:

Item Number:

Components Affected:

Reactor Pressure Vessel (RPV) head flange leak-off line originating from reactor vessel nozzle N-i17 Class 1 and Class 2 B-P (all pressure retaining components) and C-H (all pressure retaining components)

B15.20 and C7.10 Nominal Pipe Size NPS 1" carbon steel (SA-1 06, Or B) leak off piping and fittings (SA-105, Gr II) from RPV nozzle N-17 up to and including valves MS-V-i14 and MS-V-i13 and NPS 3/4" (SA-1 06 Gr B) branch piping up to and including valve MS-V-764.

2. Applicable Code Edition and Addenda

The Columbia Generating Station (Columbia) Inservice Inspection (181) fourth ten-year interval ASME Section Xl Code is the 2007 Edition through 2008 Addenda.

3. Applicable Code Requirement

System Leakage Test of Class 1 pressure retaining components per Table IWB-2500-1, Examination Category B-P, Item No. Bi15.20: as referenced in Table IWB-2500-1, IWB-5220, System Leakage Test, subparagraph IWB-5221 (a) indicates that system leakage tests shall be conducted at a pressure not less than the pressure corresponding to 100% rated reactor power.

System Leakage Test of Class 2 pressure retaining components per Table IWC-2500-1, Examination Category C-H, Item No. C7.10: as referenced in Table IWC-2500-1, IWC-5220, System Leakage Test, subparagraph IWC-5221 indicates that system leakage tests shall be conducted at the system pressure obtained while the system, or portion of the system, is in service performing its normal operating function or at the system pressure developed during a test conducted to verify system operability (e.g., to

GO2-1 6-012 Page 2 of 6 demonstrate system safety function or satisfy technical specification surveillance requirements).

Table IWC-2500-1 specifies a frequency of once per period.

4. Reason for Request

At Columbia the RPV flange seal leak detection piping is ASME Class 1 up to the equipment drain isolation valve MS-V-i13 and the instrument isolation valve MS-V-753.

The piping is ASME Class 2 from the instrument isolation valve (MS-V-753) up to the test connection valve MS-V-764 (See Figure 2). The RPV flange seal leak detection piping is separated from the reactor pressure boundary by one passive membrane, which is an 0-ring, located on the vessel flange. A second 0-ring is located on the opposite side of the tap in the vessel flange (See Figure 1). This piping is required during plant operation in order to detect failure of the inner flange seal 0-ring. Failure of the 0-ring would result in the annunciation of an alarm in the Control Room via pressure switch MS-PS-34 (See Figure 2). Failure of the inner 0-ring is the only condition under which this line is pressurized. Therefore, the line is not expected to be pressurized during the system pressure test following a refueling outage.

The configuration of this piping precludes system pressure testing while the vessel head is removed because the configuration of the vessel tap, coupled with the high test pressure requirement, prevents the tap in the flange from being temporarily plugged or connected to other piping. The opening in the flange is smooth walled, making the effectiveness of a temporary seal very limited. Failure of this seal could possibly cause ejection of the device used for plugging or connecting to the vessel.

The configuration also precludes pressure testing with the vessel head installed because the seal prevents complete filling of the piping, which has no vent available.

The top head of the vessel contains two grooves that hold the 0-rings. The 0-rings are held in place by a series of retainer clips that are housed in recessed cavities in the flange face. If a pressure test was performed with the head on, the inner 0-ring would be pressurized in a direction opposite to what it would see in normal operation. This test pressure would result in a net inward force on the inner 0-ring that would tend to push it into the recessed cavities that house the retainer clips. The thin 0-ring material would very likely be damaged by this inward force.

Purposely failing or not installing the inner 0-ring in order to perform a pressure test would require replacing the new outer and possibly the new inner 0-ring each time the test is conducted. This would result in additional time needed during the outage and additional radiation exposure to personnel associated with the removal and reinstallation of the RPV head.

It is possible to pressurize the Class 2 portion only by closing MS-V-753 and pressurizing with an external source at the test connection point. The piping

G02-1 6-012 Page 3 of 6 for this portion is less than 2 feet and constructed of 3/4A inch piping. When this task was performed in 2015 the total dose received was 64 mrem and no leakage was reported.

Performance of this task each inspection period in accordance with Table IWC-2500-1, Category C-H, Item C7.10 would impose more dose than performing a combined Class 1 and Class 2 examination once at or near the end of the interval in accordance with this request.

5. Proposed Alternative and Basis for Use

In lieu of the pressure requirements of IWB-5221 (a) & IWC-5221, Columbia proposes to perform a VT-2 visual examination with the affected components subject to static pressure head with the RPV head removed and the refueling cavity filled to its normal refueling water level for at least four (4) hours. The static head developed with the leak-off lines filled with water will allow for detection of pressure boundary failures. The high point of the leak-off line is at nozzle N-i17 located on the underside of the RPV flange.

The top of the RPV flange is at elevation 583.1 feet and the flange thickness is 26 inches (2.2 feet). Nozzle N-17 originates at elevation 580.9 feet (583.1 - 2.2). Per procedure, the refueling cavity is filled to the fuel pool level during refueling outages.

Water level is maintained in the fuel pool above the alarm level of 605.4 feet. Therefore the minimum head pressure in the leak-off line is 24.5 feet (605.4 - 580.9) of water.

This proposed test methodology is identical to that presented in Code Case N-805 (Reference 1). This Code Case has not yet been approved by the NRC and is not yet identified in the current revision of Regulatory Guide 1.147, "In-service Inspection Code Case Acceptability, ASME Section Xl, Division 1" (Reference 2).

Columbia proposes to perform this test once at or near the end of each interval for both the Class 1 and Class 2 portions of the line. Once per interval testing is consistent with IWB-5222(b) requirements and reduces the dose received during testing of the Class 2 portion.

The leak-off piping exits the RPV flange at the 0 degree azimuth just above the ladder to the 568 feet elevation platform. The line exits the RPV flange at the N-i17 nozzle which is behind a 40 inch x 42 inch removable insulation panel. From nozzle N-17 to the first elbow is approximately 22 inches with the first elbow six inches below the top of the access panel. The elbow directs the piping out through the insulation panel and away from the RPV into the containment volume. From there the piping extends approximately 20 feet around the RPV to pressure switch MS-PS-34 near the 270 degree azimuth. Access is available all the way around the RPV at this level so a VT-2 examination can be performed on the leak-off piping for evidence of leakage up to the ASME Section Xl Code boundary valves. There is no other insulation on the leak off line except for the N-i17 insulation panel. The piping is at approximately 579 feet elevation. An averaged sized individual at the platform at elevation 568 feet will be able to examine the piping using standard VT-2 tools such as mirrors and binoculars as needed. In the event portions of the pipe are obstructed from view, the examiner will

G02-1 6-012 Page 4 of 6 look for indications of leakage on adjacent piping and surrounding area per IWA-5241 requirements. If signs of leakage are observed in the areas surrounding the N-17 insulation panel, the panel will be removed for further examination of the leak-off piping.

Columbia performs a VT-2 inspection of the Class 1 portion of the head flange leak-off line each refueling outage in accordance with IWB-5222(a). A review of work order history, condition reports and Operations Logs shows no record of Columbia ever having a reactor pressure vessel flange 0-ring leakage event or leakage in the leak-off piping. In July of 1992 there was an inadvertent pressure switch alarm annunciation from MS-PS-34 during start-up caused by residual water in the leak-off line that had flashed to steam. The calibration procedure was revised to include draining the line.

Should the inner 0-ring leak during the operating cycle, it will be identified through the alarm of a pressure switch in the main control room. Upon receiving an alarm, operator actions will involve monitoring: (1) drywell floor drain leakage per site procedures; (2) drywell temperature and pressure per site procedures; (3) containment radiation monitors located in the control room; and (4) drywell fission products. If monitoring actions indicate a pressure boundary failure (outer seal failure), operators are directed per the annunciator response procedure to Technical Specification 3.4.5, Reactor Coolant System (RCS) Operational Leakage. Similarly, should the inner 0-ring leak during the operating cycle and a through wall leak of the reactor vessel flange leak-off piping exist, leakage will be detected in the same manner described above for leakage resulting from outer seal failure. Since there is reasonable assurance that the proposed alternate examination will detect gross indications of leakage should any exist from this piping, Columbia requests authorization to use the proposed alternative pursuant to 10 CFR 50.55a(z)(2) on the basis that compliance with the specified requirement would result in hardship or difficulty without a compensating increase in the level of quality and safety.

6. Duration of Proposed Alternative

The duration of this request is for the fourth inservice inspection interval ending December 12, 2025.

7. Precedents

7.1 The following precedents pertain to approved relief requests for leak-off lines classified as ASME Code Class 1 using Code Case N-802:

(a) Columbia submitted Inservice Inspection (ISI) Program Request 31S1-15,

[ML14077A173] on March 7, 2014, requesting use of Code Case N-805 for the Class 1 leak-off line. This request was supplemented by Response to Request for Additional Information for Relief Request 31S1-15 [ML14245A058], on August 21, 2014. The Request for use of code case N-805 was granted to Columbia Generating Station, Request for Alternative 31S1-15 to the Requirements of the ASME Code (TAC NO.

G02-1 6-012 Page 5 of 6 MF3562), February 13, 2015, Docket No. 50-397 [ADAMS Accession No. ML15037A005]. Note that Columbia's present request also incorporates use of Code Case N-805 for Code Class 2 pressure containing components as well.

(b) Millstone Power Station, Unit No. 3 - Issuance of Relief Request IR-3-1 1 Regarding Use of American Society of Mechanical Engineering Code, Section Xl, 2004 Edition (TAC No. ME1 263); April 29, 2010; Docket No. 50-423 [ADAMS Accession No. ML101040042]

(c) Limerick Generating Station, Units 1 and 2, Evaluation of Relief Requests RR-33, RR-34 and RR-35, Associated with the Second In-service Inspection interval (TAC Nos. MD8071, MD8073, MD8074, MD8075, and MD8076); January 27, 2009; Docket Nos. 50-352 and 50-353 [ADAMS Accession No. ML090060218]

(d) North Anna Power Station, Unit No's. 1 and 2 Re: ASME Code Third 10-year ISI Program. (TAC No's MC5588, MC5589, MC5590, MC5591, MC5592, MC5593, MC5594, MC5595, MC5599 and MC5600); February 9, 2006; Docket Nos. 50-338 and 50-339 [ADAMS Accession No. ML060450517]

7.2 The following precedents pertain to approved relief requests for leak-off lines classified as ASME Code Class 2 using Code Case N-802:

(a) Vermont Yankee, Vermont Yankee Nuclear Power Station - Relief Request lSl-PT-02: Fourth 10-Year Inservice Inspection Interval, approved by the NRC in a letter dated March 1, 2013 [ADAMS Accession No. ML13055A009]

(b) Dresden, Units 2 and 3, Dresden Nuclear Power Station, Units 2 and 3 - Safety Evaluation in Support of Request for Relief Associated with the Fifth 10-Year Inservice Inspection Interval Program", Enclosure 3 approved by the NRC in a letter dated September 30, 2013 [ADAMS Accession 1\\10. ML13258A003]

8. References

1) Code Case N-805, "Alternative to Class 1 Extended Boundary End of Interval or Class 2 System Leakage Testing of the Reactor Vessel Head Flange 0-Ring Leak-Detection System," approved by the American Society of Mechanical Engineers (ASME) on February 25, 2011

2) Regulatory Guide 1.147, "lnservice Inspection Code Case Acceptability, ASME Section Xl, Division 1," Revision 17 dated August 2014

G302-1 6-012 Page 6 of 6 0.12" mai diameter hoe.

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Figure 1 Detail of RPV Head Flange Leak Detection Tap rMS,-V-7M 4 ciass2 To Equipment bri 3/4" MS(60).4.4-NI ?

MS-V-li s-.,5~50-.-4 MS*-V-14 Figure 2 RPV Seal Leak-off Detection Line Schematic

6>,!

' **;j* *, ENERGY

i NORTHWEST Alex L. Javorik Vice President, Engineering P.O. Box 968, Mail Drop PE20 Richiand, WA 99352-0968 Ph. 509-377-8555 F. 509-377-4317 aljavorik@ energy-northwest.com FE8 1 7' 20]18 10 CFR 50.55a G02-1 6-012 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Subject:

COLUMBIA GENERATING STATION, DOCKET NO. 50-397; INSERVICE INSPECTION (ISI) PROGRAM RELIEF REQUEST 41S1-05

Reference:

Code Case N-805, "Alternative to Class 1 Extended Boundary End of Interval or Class 2 System Leakage Testing of the Reactor Vessel Head Flange 0-Ring Leak-Detection System," approved by the American Society of Mechanical Engineers (ASME) on February 25, 2011...

Dear Sir or Madam:

Pursuant to 10 CFR 50.55a(z)(2), Energy Northwest hereby requests NRC approval of the following relief request for the fourth ten-year inservice inspection (181) program interval at Columbia Generating Station ending December 12, 2025. Energy Northwest has determined that compliance with certain inspection requirements of ASME Section XI would result in unnecessary hardship or unusual difficulty without a compensating increase in the level of quality and safety. The details of the 10 CFR 50.55a request are enclosed as.

Energy Northwest requests approval within one year of the date of the submittal to accommodate application of the request during the next refueling outage.

There are no new commitments made in this submittal. If you have any questions or require additional information, please contact Ms. L.L: Williams at 509-377-3148.

Executed this /7t' day, of.L/"LL 2016.

Respectfully, Vice President, Engineering

Attachment:

(1)10 CFR 50.55a Relief Request Number 4,S,-05

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