ULNRC-05226, Responses to Requests for Additional Information Concerning License Amendment Request (LAR) OL-1258 for Revision of Technical Specification 3.7.3, Main Feedwater Isolation Valves (Mfivs).

Responses to Requests for Additional Information Concerning License Amendment Request (LAR) OL-1258 for Revision of Technical Specification 3.7.3, Main Feedwater Isolation Valves (Mfivs).

ML053200450
Person / Time
Site:	Callaway
Issue date:	11/03/2005
From:	Marilyn Evans AmerenUE, Union Electric Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
ULNRC-05226
Download: ML053200450 (8)

Text

AmerenUE PO Box 620 Callaway Plant Fulton, MtO 65251 November 03, 2005 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station P1-137 Washington, D.C. 20555-0001 Ladies and Gentlemen: ULNRC-05226 DOCKET NUMBER 50483 CALLAWAY PLANT WAmeren UNION ELECTRIC COMPANY RESPONSES TO REQUESTS FOR UE ADDITIONAL INFORMATION CONCERNING LICENSE AMENDMENT REQUEST (LAR) OL-1258 FOR REVISION OF TECHNICAL SPECIFICATION 3.7.3, "MAIN FEEDWATER ISOLATION VALVES (MFIVsr'

References:

1)ULNRC-05206, dated September 9, 2005

2) ULNRC-05224, dated October 24, 2005 Reference 1 (ULNRC-05206) transmitted to the NRC AmerenUE's (Union Electric) requested amendment of the Facility Operating License for the Callaway Plant (License No. NPF-30) to revise Technical Specification (TS) 3.7.3, "Main Feedwater Isolation Valves (MFIVs)." The primary change proposed per the amendment request (which is still under review by the NRC) is to revise the stroke time test requirement for the MFIVs such that the single-value 15-second stroke time limit currently specified in TS 3.7.3 for the MFIVs would be replaced with a reference to a figure that specifies the stroke time limit as a function of steam generator steam pressure.

Reference 2 (ULNRC-05224) transmitted a supplement to the original amendment request in order to partially modify the changes that were originally proposed, and to provide additional information in response to questions/requests for additional information from the NRC. Subsequent to the Reference 2 submittal, AmerenUE received additional questions from the NRC.

This letter provides AmerenUE's responses to the additional NRC questions. Specifically, Attachment I to this letter provides statements of the questions and the AmerenUE responses. In addition, Attachment 2 to this letter provides a color version of the MFIV Performance Curve that was originally provided to the NRC as Attachment 6 to Reference I (ULNRC-05206).

a subsidiary olAmeren Corporation

ULNRC-05226 November 03, 2005 Page 2 In providing this additional information, the determination pursuant to 10 CFR 50.92 that the proposed license amendment request and its supplement does not involve a significant hazard consideration, including the basis for that determination, remains unchanged.

Please contact us for any questions you may have regarding this transmittal of additional information.

I declare under penalty of perjury that the foregoing is true and correct.

Very truly yours, Executed on: November 03, 2005 Michael S. Evans Manager, Business Operations DJW/jdg Attachments: 1) Responses to NRC Questions Regarding LAR OL-1258

2) MFIV Performance Curve

ULNRC-05226 November 03, 2005 Page 3 cc: U.S. Nuclear Regulatory Commission (Original and I copy)

Attn: Document Control Desk Mail Stop P1-137 Washington, DC 20555-0001 Mr. Bruce S. Mallett Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011-4005 Senior Resident Inspector Callaway Resident Office U.S. Nuclear Regulatory Commission 8201 NRC Road Steedman, MO 65077 Mr. Jack N. Donohew (2 copies)

Licensing Project Manager, Callaway Plant Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Mail Stop 7E1 Washington, DC 20555-2738 Missouri Public Service Commission Governor Office Building 200 Madison Street PO Box 360 Jefferson City, MO 65102-0360 Deputy Director Department of Natural Resources P.O. Box 176 Jefferson City, MO 65102

ULNRC-05226 ATTACHMENT 1 RESPONSES TO NRC QUESTIONS REGARDING LAR OL-1258

Responses to NRC Questions Regarding LAR OL-1258

1. The 15 seconds in the currentSR 3.7.3.1 is basedon the premise that any higher closure time would be an indication of degradationofthe valve. Therefore, the NRC staff needs to know that higher closure times below 500psig SG pressure (SGP) in the proposedFigure3.7.3-1 ivould not be showing that the MFIV being tested has degraded

Response

The main feedwater isolation valves (MFIVs) are tested under the Inservice Testing (IST)

Program. Valves tested under the IST Program are governed by the testing requirements of the ASME OM Code. The ASME OM Code requires that stroke time test results shall be compared to the initial reference values or new reference values established for subject valves. Although the stroke-time limits for the MFIVs are being changed (pursuant to the license amendment request), the ASME OM Code test requirements will not change for the main feedwater isolation valves.

When comparing the stroke time test results to the initial reference values, the ASME OM Code specifies, for each type of valve (based on actuator type), the exact stroke time ranges to be used for stroke time acceptance criteria. If a valve fails to meet the stroke time acceptance criteria range, the valve shall be immediately retested or declared inoperable. If the valve is retested and the second set of data also does not meet the stroke time acceptance criteria range, the data shall be analyzed within 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> to verify that the new stroke time represents acceptable valve operation, or the valve shall be declared inoperable. If the second set of data meets the acceptance criteria, the cause of the initial deviation shall be analyzed and the results documented in the record of tests.

Valves declared inoperable may be repaired or replaced, or the data may be analyzed to determine the cause of the deviation. The latter may yield a determination, in some cases, that the valve is operating acceptably. [ASME OM Code 1988 Part 10 Paragraphs 4.2.1.8 and 4.2.1.9]

When new reference values are established, the ASME OM Code specifies that reference values shall only be established when the valve is known to be operating acceptably.

Deviations between the previous and new reference values shall be identified and analyzed. Verification that the new values represent acceptable operation shall be documented in the record of test. [ASME OM Code 1988 Part 10 Paragraph 3.3 and 3.4]

Therefore, although longer stroke times would be noted for the MFIVs at lower pressures (consistent with the characteristics of the system-medium actuators for these valves),

application of the Code-required reference value and acceptance range for each MFIV will ensure that valve degradation is detected or investigated. This would be true for any test pressure since, as explained in the response to the next question, for a deviation seen at one particular test pressure a deviation would also be seen at any other test pressure (in relation to the characteristic stroke-time curve established for the MFIVs).

Attachment 1 ULNRC-05226 Page 3

2. What are the conditions that the MFIVs would be tested at to be in accordance with the proposed SR 3.7.3.3, andwhat is the basis that testing an MFIV at those conditions ensures that the valve closure times at other conditions would meet the proposedFigure3.7.3-1?

Response

Per the proposed surveillance test procedure to be used for implementing SR 3.7.3.3, the MFIVs will be tested at a nominal system pressure (steam generator steam pressure) of approximately 100 psig (during Mode 4, prior to entry into Mode 3). As described in the response to Question 1 above, testing at this point will provide a reference stroke time value that will be used to establish the test acceptance criteria for each MFIV under the IST program.

As described in the amendment request, the proposed TS acceptance curve for SR 3.7.3.3 is based on the MFIV performance curve (provided as Attachment 6 to the September 9 amendment request). The shape of the performance curve reflects the operating characteristics of the MFIVs (with respect to how fast the valves may be expected to close at any pressure throughout the expected pressure range of operation). This curve was supported by testing done at the valve manufacturer, as well as field tests done at Callaway. In addition, and as also noted in the amendment request, the shape of the acceptance/performance curve(s) will be verified by baseline testing to be done during restart from the current refueling outage. [For the baseline testing, each MFIV will be stroked to close at five different pressures throughout the applicable pressure range. The measured stroke times will then be compared and evaluated to verify the shape of the performance/acceptance curve(s).] Since the acceptance curve is based on the characteristic curve for the valves, a deviation from the stroke time at one point on the acceptance curve would be expected to yield a proportional deviation from the stroke time at any other point on the curve.

ULNRC-05226 ATTACHMENT 2 MFIV PERFORMANCE CURVE

)f MFIV Stroke Time Curves 12 0--0 115 __- -Calculated Dual Train Stroke Time 115 _

110 _ __ -Calculated Single Train Stroke Time 105 -- Measured Dual Train Stroke Time 100 _ .

95 -_- Safety Analysis Limits 90 -_ -Sample TS Curve 85 -

Mode 3 Entry Steam Generator 80 Pressure 75 _ __

70 -

E 65 -___

4)60-255 U.

50 \

45 -

40-35 ____

30 _ _ __. ,_

25 -\ _ _

20 -__ ___

15 I I __=_7_ -- ----

10 I I I I L -

5 _

0 oo o to O LO LO O LO S e n e raOt rO PeO ( L o Lo N N M WD: W1)t1) (O CD I-- I- CD GO a) 0) O O N-Steam Generator Pressure (psig)

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