ML20078M821

Responds to Unresolved Items in Insp Rept 50-263/94-08. Corrective Actions:Util Commits to Revise IST Program Document to Include Valves CV-1728 & CV-1729

ML20078M821
Person / Time
Site:	Monticello
Issue date:	11/28/1994
From:	Hill W NORTHERN STATES POWER CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9412050144
Download: ML20078M821 (9)

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Northem States Power Company 414 Nicollet Mail Minneapolis, Minnesota 55401 1927 Telephone (612) 330-5500 November 28,1994 US Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 Response to Unresolved items Contained in inspection Report 50-263/94008 Inspection report 50-263/94008 reported the result of an Inspection conducted by Messrs. A Dunlop and J Colaccino on August 8-26,1994. The inspection consisted of a review of the Monticello program for inservice testing (IST) of pumps and valves and of the effectiveness of the program regarding check valves. Two concems were identified regarding the implementation of American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI requirements into the IST program. These items concerned testing relief valves in accordance with OM-1 and the removal of the Residual Heat Removal Service Water control valves from the IST program; unresolved items 94008-01 and 94008-02 respectively. The inspection report requested that Monticello provide a 60 day written response concerning these items.

Attachment A of this submittal provides the requested 60 day response to the two unresolved items contained in Inspection Report 50-263/94008. This letter contains the following new commitments to the NRC:

Following the Code Committee's response to our inquiry concerning the intent of OM-1, Section 4.3, Monticello will provide a supplemental response concerning Unresolved Item 94008-01.

We commit to revise our Inservice Testing Program document to include valves CV-1728 and CV-1729 to be exercised in accordance with IWV-3412.

Please contact Marv Engen, Sr Licensing Engineer, at (612) 295-1291, if you require further information.

11/23/94 NSP H:\ WORD \1STi1R94000. DOC 9412050244 DR 041128 ADOCK 05000263 PDR }I g

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q USNRC- NORTHERN STATES POWER COMPANY November 28,1994 Page 2

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W J Hill Plant Manager 1 Monticello Nuclear Generating Plant j 1

c- Regional Administrator- 111, NRC .  !

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NRR Project Manager, NRC

Sr Resident inspector, NRC State of Minnesota j Attn

Kris Sanda j . J Silberg i

l Attachments: A - Response to Unresolved items 94008-1 and 94008-2 i

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TRANSMITTAL MANIFEST NORTHERN STATES POWER COMPANY j NUCLEAR LICENSING DEPARTMENT MONTICELLO NUCLEAR GENERATING PLANT Response to Unresolved items Contained in Inspection Report 50-263/940088 Manifest Date: November 28,1994 Monticello intemal Site Distribution Special Instructions Kaleen Hilsinhoff.. . .USAR File... . .. . ... ..Yes No_X_

Steve Ludders ... . . .NRC Commitment . ...Yes_X_ No Lila Imholt.. . . . . .Monti OC Sec .. .. . .Ye s No X_ - 10, No dist to OC members below if YES Mal Opstad... . ...... ..Monti SAC Sec. . ..Yes_X_ No -6

• Mail Room .... . .Monti Posting. .. . .. .Ye s No_X_ - 7 Monticello Internal Site Distributico:

• Monti Document Control File . L H Waldinger, GM MNGP, SAC W J Hill, Plunt MGR, SAC, OC J C Grubb, NGSS, OC C A Schibonski, GSE, OC L L Nolan, GSSA, OC M F Hammer, GSM, OC B D Day, MGR MTC, OC J E Windschill, GSRS, OC Operating Experience Coord M W Onnen, GSO, OC W A Shamla, NQD Dean Carstens Monti Site Lic File l

Al Wojchouski Steve Hammer Jim Freborg NSP Internal Distribution (Ren Square,8th Floor)

E L Watzl R O Anderson, Dir LMI, SAC T E Amundson, Dir NQD, SAC Communications Dept Yes No_X_

External NSP Distribution

• Doc Control Desk, NRC Kris Sanda, State of Minn Regional Admin-lll,NRC J E Silberg, Beth Wetzel, NRR-PM, NRC Steve Ray, SR Res Insp, NRC

• Advance Distribution made by Site Licensing Correspondence Date : November 28,1994

Attachment A Response to Unresolved items 94008-1 and 94008-2 Unresolved item 94008-1 "It was unclearif the requirements for testing relief valves per OM-1 were adequately incorporatedinto test procedure 0255-02-1B, " Relief Valve Setpoint and Leak Checks." Relief valve testing as required by OM-1 stated that valves should be tested under the similar conditions that they would be expected to see during operation or accident conditions. If testing was performed at ambient conditions, then certified correlations for setpoint testing need to be developed. Several valves had correlations for testing under ambient conditions, however, sufficient information was not available to verify they were pmperty certified as required by the Code. A certified conelation as required by OM-1 should be based on either vendor orlicensee test results for similar valves under similar test conditions. This is considered an unresolved item (263/94008-1) pending furtherinformation on the setpoint correlation."

Response

Monticello test procedure 0255-02-1B, " Relief Valve Setpoint and Leak Checks" performs relief valve testing per OM-1-1981 for liquid relief valves in various ASME Class 2 and 3 safety systems. The procedure is a bench test of the relief valves after they have been removed from the system. Upon satisfactory test completion, the valves are reinstalled. We understand that the above identified unresolved item pertains to the following specific valves tested per procedure 0255-02-1B:

Relief Valve No. System Setpoint (PSIG) Cold Setpoint (PSIG)

RV-1990 A RHR 185 189 RV-1991 B-RHR 185 189 RV-1992 A-RHR 185 189 RV-1993 B-RHR 185 189 RV-2004 A-RHR 500 510 RV-2005 B-RHR 500 510 RV-2025 A-RHR 500 510 RV-2031 A-RHR 185 189 RV-4281 A-RHR 500 515 RV-4282 B-RHR 500 515 Per the standard industry practice, a relief valve is provided by the manufacturer at its design cold set pressure if the operating ambient (environment) temperature or operating fluid temperature exceeds a certain value determined by the manufacturer. For the above listed valves, the ambient temperature does not require application of a setpoint temperature correction factor. However, since the operating fluid temperature has a maximum design value ,

of 281*F, these valves are designed with the cold set pressure shown above. This allows the 11/?3/94 NSF H:\ WORD \1ST\IR94008. DOC

Attachment A Page 2 November 28,1994 valve to lift at the same nominal setpoint for any fluid temperature up to its maximum design value of 281*F.

The Monticello inservice Testing Program for testing of Class 1,2, and 3 valves is governed by the 1986 Edition of the ASME Boiler and Pressure Vessel Code (the Code),Section XI, Subsection iWV, and portions of ASME Operations and Maintenance Standards Part 10 (OM-

10) pursuant to 10 CFR 50.55a(f)(4)(iv). Subsection IWV, article IWV-3510, " Safety Valve and Relief Tests", specifies testing of these valves in accordance with ANSI /ASME OM-1-1981 (OM-1). OM-1, section 4, provides test methods for set pressure testing and seat tightness testing. OM-1 subsection 4.1.3.1 provides test media requirements for the testing of relief devices for liquid service and states:

" Valves shall be tested with the normalsystem operating fluid and temperature for which' they are designed. Altemate liquids ordifferent temperatures may be used, provided the requirements of 4.3 are met."

Section 4.3, " Alternative Test Media" states:

" Pressure relief devices may be subjected to set pressure tests and seat tightness tests using a test media (fluid and temperature) other than that for which they are designed, provided the testing complies with 4.3.1, 4.3.2, and 4.3.3".

OM-1, Sections 4.3.1,4.3.2, and 4.3.3 provide requirements for establishing certified correlations for the testing of pressure relief devices with altemate test media.

We consider the use of cold set pressure to be subjecting the valves to a set of test conditions for which they are designed and paragraphs 4.3.1,4.3.2, and 4.3.3 do not apply. The fluid temperature is a design input required by the manufacturer when procuring the valve. The valve is then supplied set at its cold set pressure. Therefore, it is evident that the cold set pressure is a design condition of the valve. The cold setpoint established in procedure 0255-02-1B is provided by the manufacturer and is stamped on the valve or is determined using correction factors provided by the manufacturer. Therefore, cold setpoint testing of these valves is not performed using alternate test media and the requirements of OM-1, section 4.3, are not applicable to the above valves of concern.

Our discussions with other licensees and valve manufacturers has confirmed that our procedure satisfies the Code. In order to provide further confirmation as to the Code's intent we have submitted the following inquiry to the Code committee:

'Does performing a cold setpoint bench test on a Class 2 liquid relief valve, where the

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cold setpoint is provided by the manufacturer, test the valve as it is designed such that 1 paragraph 4.3 and subparagraphs 4.3.1, 4.3.2, and 4.3.3 do not apply?"

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Attachment A Page 3 November 28,1994 We understand that the Code Committee will be meeting in December of 1994 and we have requested that this inquiry be placed on the agenda for the December meeting. Following the Code Committee's review of this inquiry we will provide a supplemental response concerning this issue.

Unresolved item 94008-2

"(Close) Violation (263/92010-05e). This item concemed unacceptable test results for RHRSW control valves CV-1728 and CV-1729 without being documented and evaluated as required by the Code and the IST administrative procedure. Although Form 3107 and Form 3108 were not completed at the time of the deficiency, an operability determination was performed on the valves. The required forms were subsequently completed; however, the deletion of the valves from the IST program appeared incorrect.

The evaluation for Form 3108 determined that the valves' fail-safe function was not safety-related and was beyond the plant's design basis such that the valves were deleted from the ISTprogram. This was based on the control valves being supplied by a safety-related air supply system. The licensee's evaluation determined the valves could be excluded fmm the program based the fail-safe function being non-safety related and on IWV-1200, which excludes control valves. The inspectors agreed the fail-safe function was not required to be tested since it was not safety-related. However, the valves stillperformed a specific safety function that would require theirinclusion in the program. Since the valves were normally closed, the valves were required to open to perform theirsafety-function. This function requires the valves to be exercised to the open position perIWV-3412 and stroke timed per IWV-3413.

\ The licensee was still evaluating this issue at the conclusion of the inspection. This will be considered an unresolved item (253/94008-2) pending inclusion of the valves in the IST program or adequatejustifications for their exemption. Based on the ta nresolveditem, this example of the violation is considered closed."

Response

The Residual Heat Removal Service Water (RHRSW) System function is to supply strained river water to the RHR heat exchangers which remove heat rejected by the Residual Heat Removal (RHR) System during normal reactor shutdown cooling, during reactor isolation or accident conditions, and during the time when the fuel pool has an emergency heat load from  ;

spent fuel. )

RHRSW valves CV-1728 and CV-1729 are air operated control valves on the outlet line of the j I

RHRSW side of the "A" and "B" RHR heat exchangers, respectively. These control valves maintain a differential pressure between the RHRSW process stream and the RHR process

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- Attachment A Page 4 November 28,1994 stream during RHRSW system operation. The valves are controlled by a positioner, controlled by a differential pressure indicating controller which senses pressure on the RHRSW discharge line and the RHR inlet line to the RHR heat exchanger. The desired differential pressure control point, and thus the desired valve position for system flow, is manually set by the operator. The normal air supply to these valves is plant instrument air. However, in the event of loss of plant air, air is supplied by safety related auxiliary air compressors energized from essential buses.

The Monticello inservice Testing Program for testing of Class 1,2, and 3 valves is govemed by the 1986 Edition of the ASME Boiler and Pressure Vessel Code (the Code),Section XI, i Subsection IWV, and portions of ASME Operations and Maintenance Standards Part 10 (OM-

10) pursuant to 10 CFR 50.55a(f)(4)(iv). RHRSW control valves CV-1728 and CV-1729 are Quality Group "C" components which corresponds to the ASME Boiler and Pressure Vessel l Code Class 3 classification. The valves operate in conjunction with the RHRSW pumps to i provide proper service water flow to the RHR heat exchanger, while maintaining a differential pressure between the RHRSW and the RHR process stream.Section XI, Subsection IWV, i Article IWV-1200 of the Code provides the following criteria for exemn9 ;; valves from testing:  ;

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(a) valves that have no specific function in shutting down a mactor orin mitigating the consequences of an accident and used only for: ,

I (1) operating convenience (such as manual vent, drain, instrument, or test valves); ,

(2) system control (such as pressure regulating valves); or (3) maintenance.

(b) extemal control and protection systems responsible for sensing plant conditions l and providing signals for valve operation.

The function of the control valves to open, providing a flow path for RHRSW through the RHR heat exchanger, does not allow exemption of these valves from inservice testing.

IWV-3412 states that valves shall be exercised to the position required to fulfill their function. t The required position to fulfill valve function varies for valves CV-1728 and CV-1729 based on the desired RHRSW pump combination, desired system flow conditions, and RHRSW to RHR I system differential pressure. Based on these factors, the required valve position to perform valve function will be partially open and not a full open position. IWV-3412 provides for demonstrating the necessary valve disk movement by observing indirect evidence (such as ,

changes in system pressure, flow rate, level, or temperature), which reflect stem or disk

• position. The most representative test of the capability of valves CV-1728 and CV-1729 to perform their intended function is performed during inservice testing of the RHRSW pumps.

Quarterly testing of the RHRSW pumps verifies the capability of the valves to operate properly l

, Attachment A Page5 November 28,1994 to pass the maximum required accident flow as well as the valve position necessary to achieve required flow conditions. Testing of the valves in this manner demonstrates valve performance capability as well as monitors for valve degradation.

lWV-3413 requires that a limiting value of full stroke time be established for a power operated valve. Establishment of a limiting stroke time for these valves would be purely arbitrary for code compliance and would not provide any meaningfulinformation regarding valve degradation or capability to perform their required function. Upon receipt of an automatic ECCS initiation signal, the RHRSW pumps will be automatically tripped, if they are running. If the ECCS initiation signal is coincident with the loss of off-site AC power, then the RHRSW pumps will be automatically tripped and locked out. Under conditions of a design basis accident, the low pressure coolant injection mode of RHR is used to restore the water level in the reactor core. Upon restoration of reactor water level by the RHR system, the RHRSW system must be manually started and flow established by the Reactor Operator. There are no automatic initiation signals associated with the RHRSW system. Plant procedures direct the initiation of RHRSW largely at the discretion of the Reactor Operator. Monticello Updated Safety Analysis Report, section 6.2.3.2.1, states; "The containment pressure analysis assumes that the RHR containment spray / cooling mode and the RHR service water pumps are not initiated until 600 seconds after the beginning of the accident....There is not a fixed requirement as to when the containment cooling system (RHR system with heat exchangers to remove accident and decay heat) must be placed in operation since at least eight hours are available before the containment design pressure (56 psi) is reached without cooling under DBA-LOCA condition."

RHRSW control valves CV-1728 and CV-1729 are manually positioned, from the control room, by adjustment of the air operated control valve differential pressure indicating controller to establish the desired RHRSW flow conditions. These valves do not receive an actuation signal (neither by manual handswitch nor by automatic logic) to stroke to the position required to fulfill their safety function. Performing full stroke time testing of these valves is inconsistent with the control scheme design of the valves, the functional requirements of the valves, and the manual positioning of the valves. As these valves are manually positioned and do not receive an actuation signal to full stroke to perform their specific safety function, it is not appropriate to classify them as " power operated valves" within the context of the Code, thus the requirements of IWV-3413 (as well as IWV-3417(a)) are not applicable.

We acknowledge that exclusion of these valves from the plant's Inservice Testing Program, based solely on the fail-safe function being a non-safety related function, was incorrect. Our exclusion of these valves from the program was not a conservative interpretation of the revised exclusion criteria wording of the ASME code implemented by our third ten year interval program. Operability of valves CV-1728 and CV-1729 has been demonstrated and compliance with the Code has been maintained via the existing testing requirements performed on these valves in conjunction with quarterly RHRSW pump testing. We commit to l

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Attachment A Page 6 November 28,1994 revise our Inservice Testing Program document to include valves CV-1728 and CV-1729. The valves are to be included in the program as Category "B" valves with the following requirements of Section XI applied: IWV-3411, IWV-3412, IWV-3416, and IWV-3417(b).

These valves are not subject to the requirements of IWV-3413 nor IWV-3417(a) because they do not act as power operated valves and are not classified as power operated valves as described above. We have performed a review of plant systems to determine if any additional control valves with specific safety functions are not included in the plant's Inservice Testing Program. No other valves were identified.