L-2014-073, Inservice Inspection Plan Relief Request No. 14

Inservice Inspection Plan Relief Request No. 14

ML14078A031
Person / Time
Site:	Turkey Point
Issue date:	03/14/2014
From:	Kiley M Florida Power & Light Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-2014-073
Download: ML14078A031 (10)

Text

March 14, 2014 L-2014-073 10 CFR 50.55a FPL.

U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 RE: Turkey Point Units 3 and 4 Docket Nos. 50-250 and 50-251 Inservice Inspection Plan Relief Request No. 14 On February 25, 2014, the U.S. Nuclear Regulatory Commission (NRC) issued information notice (IN) 2014-02, Failure to Properly Pressure Test Reactor Vessel Flange Leak-off Lines, identifying instances in which inspection of the reactor vessel flange leak-off lines were not performed as required by Section XI of the American Society of Mechanical Engineers (ASME)

Code and 10 CFR 50.55a.

Florida Power & Light Company (FPL) reviewed the information for applicability for Turkey Point Units 3 and 4 and determined that the required system leakage test of the reactor vessel flange leak-off lines, as described by ASME Code Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, was not previously performed.

In order for Turkey Point Units 3 and 4 to comply with NRC's regulations as provided by 10 CFR 50.55a(g)(4), and pursuant to 10 CFR 50.55a(a)(3)(ii), FPL requests relief from ASME Code,Section XI, 1998 Edition with 2000 Addenda, section IWC-2500-1, which requires that a system leakage test be conducted in accordance with IWC-5220, for the Class 2 reactor vessel flange seal leak-off line, each inspection period.

Relief Request No. 14 is attached herein for review and approval.

Turkey Point Units 3 and 4 are in the last period of the Fourth Ten-Year Inservice Inspection (ISI) Interval. The Turkey Point Unit 3 Cycle 27 and the Turkey Point Unit 4 Cycle 28 are the last refueling outages in the last period of the Fourth Ten Year ISI Interval.

The Turkey Point Unit 3 refueling outage for Cycle 27 is currently scheduled to begin on March 17, 2014, and the Turkey Point Unit 4 refueling outage for Cycle 28 is scheduled in the fall of 2014. According to the Unit 3 refueling outage schedule, the last opportunity to perform the proposed alternative examination for the reactor vessel flange leak-off line is on April 5, 2014.

Per 10 CFR 50.55a(a)(3), any proposed alternatives must be submitted and authorized prior to implementation. Considering the circumstances surrounding the late submittal of this relief due to the late discovery of the inadequate reactor vessel flange leak-off line testing, FPL requests NRC to approve the attached Relief Request No. 14 by April 4, 2014.

Florida Power & Liqht Com any 9760 SW. 344' Street Homestead, FL 33035

L-2014-073 Page 2 Relief Request No. 14 is requested on the basis that hardship and unusual difficulty exists without compensating increase in the level of quality and safety. As discussed in the attached Relief Request, the use of the proposed alternative examination provides reasonable assurance of structural integrity or leak tightness of the subject components.

If you have any questions or require additional information, please contact Robert Tomonto, Licensing Manager, at (305) 246-7327.

Very truly yours, Michael Kiley Site Vice President Turkey Point Nuclear Plant Attachment cc: Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, Turkey Point Plant

L-2014-073 Attachment Relief Request No. 14 Turkey Point Units 3 and 4 Proposed Alternative in accordance with 10 CFR 50.55a (a)(3)(ii)

Hardship or Unusual Difficulty Without Compensating Increase in Level of Quality or Safety ASME CODE COMPONENTS AFFECTED:

ASME Code Class: Code Class 2

References:

ASME Section Xl, Table IWC-2500-1, and IWC-5220 Examination Category: C-H (All Pressure Retaining Components)

Item Number: C7.10 Components for Unit 3: Reactor Pressure Vessel Flange Leak-off Detection Lines 1 inch Piping, approximately 20 feet long Stainless Steel A376 TP 316, Schedule 160, Design Pressure is 2510 psig at 680°F 3/8 inch Tubing, approximately 42 feet long, Nominal Wall Thickness of 0.065 inches.

Stainless Steel A 249 or A 213 Design Pressure is 2500 psig at 650°F Isolation Valve 3-502, 3/8 inch globe valve Components for Unit 4: Reactor Pressure Vessel Flange Leak-off Detection Lines 1 inch Piping, approximately 20 feet long Stainless Steel A376 TP 316, Schedule 160, Design Pressure is 2510 psig at 6801F 3/8 inch Tubing, approximately 38 feet long, Nominal Wall Thickness of 0.065 inches.

Stainless Steel A 249 or A 213 Design Pressure is 2500 psig at 6501F Isolation Valve 4-502, 3/8 inch globe valve Page 1 of 6

L-2014-073 Attachment APPLICABLE CODE EDITION AND ADDENDA:

The code of record for Turkey Point Units 3 and 4 for the Fourth 10-year In-service Inspection (ISI) interval is the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV),Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components," 1998 Edition with Addenda through 2000.

APPLICABLE CODE REQUIREMENT:

System Leakage Test of Class 2 pressure retaining components per ASME B&PV Code,Section XI, 1998 Edition with Addenda through 2000, Table IWC-2500-1, Examination Category C-H, (Item No. C7.10) are to occur each inspection period. Paragraph IWC-5221 "System leakage tests shall be conducted at the system pressure obtained while the system or portion of the system is inservice performing its normal operating function or at the system pressure developed during a test conducted to verify system operability."

Per IWC-5222(a), "The pressure retaining boundary includes only those portions of the system required to operate or support the safety function up to and including the first normally closed valve (including safety or relief valve) or valve capable of automatic closure when the safety function is required."

REASON FOR REQUEST:

On February 25, 2014, the U.S. Nuclear Regulatory Commission (NRC) issued information notice (IN) 2014-02, Failure to Properly Pressure Test Reactor Vessel Flange Leak-off Lines, identifying instances in which inspection of the reactor vessel flange leak-off lines were not performed as required by Section Xl of the American Society of Mechanical Engineers (ASME)

Code and 10 CFR 50.55a. Florida Power & Light Company (FPL) reviewed the information for applicability for Turkey Point Units 3 and 4 and determined that the required ASME Code,Section XI system leakage test of the reactor vessel flange seal leak-off detection lines, was not previously performed. A historical search of station operating experience for the past 10 years found no incidents of reactor pressure vessel flange O-ring leakage or leak-off line degradation.

FPL is seeking to comply with the appropriate regulatory requirements regarding examination of the reactor vessel flange seal leak-off detection lines.

The reactor vessel head gasket face is machined to accommodate two silver-plated self-energizing stainless-steel O-ring gaskets and 24 sets of wire clips (12 per O-ring). The two metal O-ring gaskets form a positive seal between the reactor head and shell, thus ensuring that no leakage of coolant occurs. This surface does not come in contact with the reactor coolant and, therefore, is not a wetted surface. Twelve wire clips hold each O-ring to the reactor head, for when the head is being lowered onto the reactor vessel or lifted off. Once the head is seated on the reactor vessel flange, the clips serve no function. Both the O-rings and wire clips are replaced each time the reactor head is removed. An O-ring seal arrangement contains leakage between the reactor vessel head flange and the vessel shell flange.

Two concentric grooves are machined into the vessel shell flange, one between the inner and outer O-rings and the other just outside the outer O-ring. These grooves are tapped and piped to the Reactor Coolant Drain Tank (RCDT). A temperature indicator common to both pipes provides a high-temperature indication and alarm in the control room (if the temperature reaches 150'F it triggers the "REACTOR VESSEL FLANGE LEAK-OFF HIGH TEMPERATURE" alarm on annunciator A, window 3/6). If the inner O-ring seal begins to leak, the leak-off pipe will be isolated and the outer O-ring is relied upon to prevent further reactor coolant leakage.

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L-2014-073 Attachment The inner leak-off line and outer O-ring up to and including the manual isolation valve 502 (see attached drawings) are categorized as Code Class 2 (Quality Group B) components. The isolation valve and the outer O-ring serve as the second isolation barrier. The B-to-D class break is assigned at the isolation valve 502. This valve is normally open since it is required to provide system function i.e., an open flow path from the inner O-ring annulus to the non-safety related RCDT. Valve 502 is procedurally isolated upon detection of an inner vessel O-ring leak and valve 501 (manual isolation valve on the outer leak-off line) is opened to indicate the outer O-ring integrity. Since the inner and outer seal rings will serve as two isolation barriers in series, the outer leak-off line up to manual isolation valve 501 is classified as non-code piping. The non-code components are not subject to ASME, Section Xl Code Examination requirements.

IWC-5221 states that the system leakage test 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. The configuration of the reactor vessel flange leak-off detection lines is such that the piping, tubing, and valve are not capable of being pressure tested at normal reactor operating pressure (approximately 2235 psig), unless the inner O-ring seal fails or is intentionally failed or is removed. The only other viable option would be a design change to perform Code compliant leakage test.

If a design change were to be implemented with the intent to hydrostatically pressurize the line, a new test connection would need to be added for the pump skid to be attached. This test would be scheduled with the head removed to allow any trapped air to escape through the holes on the vessel flange. Performing the test with the head removed will require the installation of a plug in the inner tap (something to act as a pressure boundary) which poses a concern for the potential introduction of foreign material to the vessel internals during the implementation of the modification and any reoccurring installations.

If the test was to be performed with the vessel head installed, a vent would need to be added to allow any air to escape. The pump skid could be used to help remove the air prior to testing.

The vent line would need to be added close to the reactor vessel flange where dose rates are elevated. Performing the leakage test under this configuration would pressurize the inner O-ring in a direction opposite to its normal operating direction. This would result in a net force on the inner O-ring that would tend to push it into the recessed cavity that houses the retainers.

Therefore, the inner O-ring material and/or retainers could be damaged by the net force.

In the above scenarios, if the test connection fails during the test, personnel safety and equipment integrity could be compromised. The end result of these modifications would require numerous man hours that would result in additional radiological exposure without a commensurate increase in the level of quality and safety.

The option to intentionally fail or remove the vessel flange inner O-ring in order to establish normal operating pressure and temperature test conditions on the leak-off piping and tubing would result to an additional 6 days due to another removal and re-installation of the reactor vessel head to install the new O-ring. This option would subject individuals performing the tasks to a dose of about 3.1 REM. The additional time and dose associated with this option do not result in an increase to the level of quality and safety that would justify the additional burden.

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L-2014-073 Attachment The performance of the actual pressure test would take an estimated 30 minutes in either option. The quality of examination in these options would be the same. The time and dose accumulated to perform the test in each case and the lack of difference in the quality of examinations do not result in an increase to the level of quality and safety that would justify the additional burden. Accordingly, these options are not considered to be viable due to time and considerable dose without a commensurate increase to the health and safety of the public.

Based on the above, compliance with the IWC-5221 system pressure test requirements will result in an unnecessary hardship without a sufficient compensating increase in the level of quality and safety.

Accordingly, FPL requests relief from IWC-5221 for Turkey Point Units 3 and 4 in accordance with 10 CFR 50.55a(a)(3)(ii) on the basis that hardship or unusual difficulty exists, without a compensating increase in the level of quality and safety.

PROPOSED ALTERNATIVE AND BASIS FOR USE:

In lieu of the requirements of IWC-5221, the following alternative examination is proposed: The Code Class 2 portions of the reactor vessel flange leak-off system shall be examined using the VT-2, visual examination method. For Code Class 2 components whose external surfaces are inaccessible for direct VT-2, the IWA-5241 (b) provisions will apply. The test shall be conducted at ambient conditions after the refueling cavity has been filled to its normal refueling water level for at least 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

This examination will be performed once an inspection period for the remaining of the Fourth 10-Year Inservice Inspection (ISI) Interval as defined in Table IWC-2500-1. During this examination, a procedure will be used to ensure that the leak-off line is water solid, prior to the beginning of the four hour pressurization hold time. This procedure will consist in using the RCDT flow path to remove any air trapped in the leak-off lines after the reactor cavity has been filled to its normal refueling water level.

The refueling water level is limited at 57 feet 3 inches. The static head pressure at the reactor vessel head leak-off line, at the lowest Code Class 2 component elevation, is approximately 16 psig. The refueling cavity typically maintains this static head pressure for approximately 14 days during a refueling outage.

The reactor vessel flange leak-off line is essentially a leakage collection/detection system and would only function as a Class 2 pressure boundary if the inner O-ring fails, thereby pressurizing the piping, tubing, and valve. If the inner O-ring would fail, the piping would be exposed to a normal operating pressure of approximately 2235 psig, which is below the design pressure of the leak off piping and tubing which are 2510 and 2500 psig respectively.

If the inner O-ring leaks during the operating cycle, it will be identified by an increase in temperature of the leak-off line above ambient temperature. This leak detection piping and tubing configuration has a temperature indicator in the Control Room and is monitored per Turkey Point Units 3 and 4 Technical Specifications 3/4.4.6 "Reactor Coolant System Leakage".

Should the temperature in the flange leak-off line increases to 150OF or greater, an alarm in the Control Room will be actuated. This alarm is closely monitored by procedurally controlled operator actions allowing identification of any further compensatory actions required.

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L-2014-073 Attachment In the event that leakage past the inner O-ring develops in the reactor vessel flange leak-off line during normal operation, this leakage would be detected through reactor coolant system water inventory balance surveillance, or through the containment atmosphere/particulate radioactivity monitor surveillance, or by containment sump level surveillance. Therefore, detecting leakage past the inner O-ring while the plant is operating will be detected well ahead of posing any significant risks to safe operation of the plant.

If leakage is detected during normal operation, performing a VT-2 visual examination of the reactor vessel flange leak-off line is not justified since the Code Class 2 lines are located inside the bio-wall, and in accordance with as low as reasonable achievable (ALARA) principles, entry into the bio-wall at power is not permitted.

Any leakage due to a through-wall leak of the leak-off line or failure of the inner O-ring would be expected to clearly exhibit boric acid residue accumulation that would be discernible during the proposed alternative VT-2 visual examination that would be performed during a refueling outage. Additionally, the static head developed on the leak detection line filled with water and the time the line is filled with water will allow for the detection of any indications in the line.

Performing the proposed test with only static head pressure in the leak-off lines does not reduce the margin of safety in operating the plant or detecting leaks and therefore provides reasonable assurance of structural integrity or leak tightness of the subject Code Class 2 components.

Since there is reasonable assurance that the proposed alternative examination will detect indications of leakage should any exist from the Code Class 2 lines and that the examinations will occur once an inspection period, FPL requests authorization to use the proposed alternative pursuant to 10 CFR 50.55a(a)(3)(ii) 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.

DURATION OF PROPOSED ALTERNATIVE:

This relief is requested for and will be implemented in the remainder of the Fourth Ten-Year ISI Interval for Units 3 and 4. The Unit 3 Fourth 10-Year ISI Interval began February 22, 2004 to February 21, 2014 and the Unit 4 Fourth 10-Year Interval began April 15, 2004 to April 14, 2014.

FPL previously invoked the provision of ASME Code Section Xl, IWA-2430(d)1 to extend the Fourth 10-Year ISI interval by 1-year for both Turkey Point Units 3 and 4 to complete the required in-service inspections during the refueling outage for Cycle 27 and Cycle 28 for Unit 3 and Unit 4 respectively, and to credit those inspections/examinations to the Fourth 10-Year ISI Interval.

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L-2014-073 Attachment PRECEDENTS:

1. Arkansas Nuclear One, Unit 2, Fourth Inspection Interval Alternative Request for Relief from American Society of Mechanical Engineers (ASME) Code, Section XI-Request for Relief ANO2-ISI-015, approved by NRC in a letter dated June 27, 2013, Accession No. ML13161A241.

2. Palo Verde Nuclear Generating Station, Units 1, 2 and 3, Third Inspection Interval Alternative, Request for Relief from ASME Code,Section XI, Reactor Vessel Head Flange Leak Detection Piping-Relief Request No. 49, approved by the NRC in a letter dated April 4, 2013, ADAMS Accession No. ML13085A254.

3. Callaway Plant, unit 1, Third Inspection Interval Alternative, Proposed Alternative to ASME Section XI Requirements for Leakage Testing of Reactor Pressure Vessel Head Flange Leakoff Lines, Relief Request 13R-14, approved by the NRC in a letter dated August 13, 2013, ADAMS Accession No. ML13221A091.

4. Vogtle Electric Generating Plant-Units 1 and 2, ISI Program Alternative VEGP-ISI-ALT-10, Version 1, dated January 16, 2014, ADAMS Accession No. ML14016A488 Page 6 of 6