ML17354A303

Safety Evaluation Accepting Revised Relief Requests PR-4 & PR-5

ML17354A303
Person / Time
Site:	Turkey Point
Issue date:	10/22/1996
From:	NRC (Affiliation Not Assigned)
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NUDOCS 9610240243
Download: ML17354A303 (11)

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UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON> D.C. 20555-0001 SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO THE THIRD TEN-YEAR INTERVAL REVISION 1

INSERVICE TESTING PROGRAM FLORIDA POWER AND LIGHT COMPANY TURKEY POINT NUCLEAR POWER PLANT UNITS 3 AND 4 DOCKET NUMBERS 50-250 AND 50-251

1. 0 INTRODUCTION The Code of Federal Regulations, 10 CFR 50.55a, requires that inservice testing (IST) of certain American Society of Mechanical Engineers (ASME) Code Class 1, 2, and 3 pumps and valves be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel Code (the Code) and applicable

addenda, except where relief has been requested and granted or proposed alternatives have been authorized by the Commission pursuant to 10 CFR 50.55a(f)(6)(i),

(a)(3)(i), or (a)(3)(ii).

In order to obtain authorization or relief, the licensee must demonstrate that:

(1) conformance is impractical for its facility; (2) the proposed alternative provides an acceptable level of quality and safety; or (3) compliance would result in a hardship or unusual difficulty without a compensating increase in the level of quality and safety.

Section 50.55a(f)(4)(iv) provides that inservice tests of pumps and valves may meet the requirements set forth in subsequent editions and addenda that are incorporated by reference in 10 CFR 50.55a(b),

subject to the limitations and modifications listed, and subject to Commission approval.

NRC guidance contained in Generic Letter (GL) 89-04, "Guidance on Developing Acceptable Inservice Testing Programs,"

provided alternatives to the Code requirements determined to be acceptable to the staff and authorized the use of the alternatives in Positions 1, 2, 6, 7, 9, and 10 provided the licensee follows the guidance delineated in the applicable position.

When an alternative is proposed which is in accordance with GL 89-04 guidance and is documented in the IST program, no further evaluation is required;

however, implementation of the alternative is subject to NRC inspection.

Section 50.55a authorizes the Commission to grant relief from ASME Code requirements or to approve proposed alternatives upon making the necessary findings.

The NRC staff's findings with respect to the requested relief or proposed alternatives as part of the licensee's IST program are contained in this safety evaluation (SE).

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PDR ENCLOSURE

By letter dated January 12, 1994, Florida Power and Light Company (FPL) submitted Revision 0 of the Third Ten-Year Inservice Testing

( IST) Program for Turkey Point Units 3 and 4.

The submittal included six relief requests, of which five were reliefs from pump testing requirements (PR-1, PR-2, PR-3, PR-4, and PR-5) and one was a relief from valve testing requirements (VR-1).

By letter dated October 27, 1994, the NRC provided the Safety Evaluation related to the IST Program.

This SE approved Relief Requests PR-I, PR-2, PR-3, and VR-1.

However, for Relief Request PR-2, NRC Recommended Action Item 5.3 requested that the licensee indicate that pump vibration was being measured quarterly.

Relief Request PR-4 was approved with provisions by the October 1994 SE.

In addition, Relief Request PR-5 had been previously approved by NRC letter to FPL dated May 19, 1994.

In a letter dated October 26,

1995, FPL submitted Revision 1 to their third ten-year interval program for inservice testing of pumps and valves.

FPL's submittal of October 26, 1995 included the resubmittal of Relief Requests PR-4 and PR-5 for NRC review and approval.

Also included in FPL's submittal were responses to several action items identified in the October 1994 SE.

Relief Request PR-4, which was approved with provisions, had been revised to provide clarification on the pump differential pressure calculations, per Recommended Action Item 5.2 of the SE, and to specify those pumps to which it applied.

Relief Request PR-5, although previously approved, had been revised to address the frequency response of a new vibration measuring device.

An evaluation of relief requests PR-4 and PR-5 and the responses to the action items is provided below.

The licensee's IST program covers the third ten-year IST interval from February 22, 1994 to February 21, 2004 for Unit 3 and April 15, 1994 to April 14, 2004 for Unit 4.

The Turkey Point Nuclear Power Plant, Units 3 and 4 IST program, Revision 1,

was developed in accordance with the requirements of the 1989 Edition,Section XI, of the ASME Boiler and Pressure Vessel Code which references the ASME Operations and Maintenance Standards, Part 6 (OM-6) and Part 10 (OM-10) for IST.

2.0

~RELIEF RE UEKTE A

Pump Relief Request PR-4 proposes to use a gauge in which the presence or absence of liquid in the gauge line could produce a difference of more than 0.25X in the indicated value of the measured

pressure, provided the minimum required Code accuracy for calculation of differential pressure is met.

The gauge is used without determining the presence or absence of liquid as required for the static correction.

Pump Relief Request PR-5 proposes to measure the vibration of a pump's frequency response in which the minimum frequency is above the one-third minimum shaft rotational speed required by Code.

2.1 Pum Relief Re uest PR-4 The The affected components are shown below:

High Head Safety Injection Pumps

• -P215 A&B Component Cooling Water Pumps

• -P211 A,B,C Spent Fuel Pit Cooling Pumps

• -P212 A&B Boric Acid Transfer Pumps

• -P203 A&B applicable ASME OMb-1989, Part 6 $4.6.2.

1 states:

Gauge Lines.

If the presence or absence of liquid in a gauge line could produce a difference of more than 0.25X in the indicated valve of the measured

pressure, means shall be provided to ensure or determine the presence or absence of liquid as required for the static correction used.

2.1.1 Basis for Relief The licensee states:

2.1.2 When this requirement

[ASME OMb-1989, Part 6 $4. 6. 2. 1) is applied to low measured pressures the 0.25% limit many times results in complicated venting procedures and related health physics risks associated with the disposal of radioactive contaminated water with no commensurate improvement of test reliability.

The typical area of concern involves the suction pressure measurement.

For the applicable

pumps, discharge pressure exceeds suction pressure by at least a factor of six, for which a 0.25%

error introduced into the suction pressure measurement typically results in an error of 0.05% in the differential pressure calculation.

This is insignificant in light of the potential 6X error allowance applied to both the suction and discharge pressure instruments

([ASME OM-6,] Paragraph 4.6. l. 1).

Alternative Testin The licensee proposes:

For gauges which are not vented and do not meet the Code requirement that presence or absence of liquid in the gauge line that could affect the indicated value of the measured pressure by greater than 0.25X, the introduced error in conjunction with the specific range and accuracy of the gauges utilized will be verified to comply with the minimum Code required accuracy for calculation of differential pressure.

This calculation verifies that the square root of the sum of the errors of the specific gauges utilized, including a term to account for the error associated with the presence or absence of liquid, is less than the square root of the sum of the squares of six percent of the associated suction and discharge pressures.

2. 1.3 Evaluation The requirement (ASME OMb-1989, Part 6 $4.6.2. 1) to account for the presence or absence of liquid in pressure sensing lines is intended to ensure that accurate pressure measurements are obtained.

Pump suction pressure 'itself is not required to determine pump performance, and there are no acceptance criteria for it.

Rather, OM-6 requires monitoring of pumps based on differential pressure (centrifugal pumps) or discharge pressure (positive displacement pumps).

This is recognized in ASME/ANSI OMa-'988, Part 6, which eliminates pump suction pressure measurement as a requirement.

This was included in Section XI to help the licensee recognize that adequate suction pressure is required for proper pump operation.

Its only quantitative use is in calculating pump differential pressure, if it cannot be measured directly.

Therefore, the error in suction pressure measurement is only important to the calculated value of differential pressure.

The licensee's alternative for accounting for liquid in the gauge lines is acceptable since it meets the intent of the Code.

By letter dated July 22,

1996, the licensee provided the staff with additional information regarding this relief request.

A summary of the specific uncertainties associated with obtaining differential pressure measurements for each of the systems covered under this relief request was provided in a detailed table.

In addition, the staff verified the licensee's calculated uncertainty to meet the minimum Code required accuracy for the calculation of the differential pressure.

2. 1.4 Conclusion The proposed alternative is acceptable since the minimum Code required accuracy for the calculation of the differential pressure is met.

Since the licensee's proposed alternative provides an acceptable level of quality and

safety, the proposed alternative is authorized pursuant to 10 CFR 50.55a(a)(3)(i).

2.2 Pum Relief Re uest PR-5 The components are the Intake Cooling Water Pumps

• -P9A through *-P9C.

The applicable ASME OMb-1989 addenda, Part 6 $4.6. 1.6 states:

Frequency

Response

Range.

The frequency response range of the vibration measuring transducers and their readout system shall be from one-third minimum pump shaft rotational speed to at least 1000 Hertz (Hz).

2.2. 1 Basis for Relief The licensee states:

The speed of the intake cooling water (ICW) pumps is approximately 900 rpm [revolutions per minute] relating to a rotational frequency of 15 Hz.

In order to satisfy the requirements of

Paragraph 4.6. 1.6, a vibration measurement system capable of measuring vibration to a lower limiting frequency of 5 Hz would be required.

The instruments currently being used at Turkey Point Nuclear Power Plant have a lower frequency limit of 420 CPM [cycles per minute]

or 7 Hz.

This instrumentation is "state-of-the-art" industrial

grade, high quality equipment.

Satisfying the Code requirements with respect to frequency response would require the unnecessary procurement of new and more sophisticated equipment beyond that intended by the Code.

Monitoring lower frequencies (less than rotational speed) is performed primarily for the purpose of detecting oil whirl in the pump bearings.

Other conditions that could result in low frequency vibration (less than shaft speed) are included in the general category of mechanical "rub" which is not considered to be significant from the aspect of pump degradation.

The use of the existing instrumentation as specified by the alternate testing will adequately provide for monitoring pump condition for the following reasons:

a)

For vertical shaft equipment rotating at these

speeds, oil whirl is an unlikely pheromenon; and b)

If oil whirl were to occur, it would be manifested at a

frequency equal to one-half of the rotational frequency, or, in this case, approximately 7.5 Hz, which is well within the range of the proposed instrumentation.

Vibration measurements taken on these pumps with instruments capable of monitoring frequencies to 7

Hz are adequate for assessing the operational readiness of these pumps as required by the Code.

2.2.2 Alternative Testin The licensee proposes:

The instruments used for measuring vibration on the ICW pumps will have a frequency response range that extends to a lower limiting frequency of 7 Hz or less.

2.2.3 Evaluation Section XI, IWP, required a vibration Frequency response range from I/2 minimum speed to at least maximum pump shaft rotational speed.

OM-6 revised the vibration frequency response to I/3 minimum pump shaft rotational speed to at least 1000 Hertz 'to more adequately envelope all potential noise contributors.

The Code requirements for frequency response ranges are general in order to cover the various types of pumps installed in safety-related

applications in nuclear power plants.

Moreover, the frequency spectrum of the complex signals generated by machines is characteristic of each machine or each pump, constituting a unique pattern, referred to as the "machine signature."

Analysis of the signature allows identification of vibration

sources, and monitoring of the change over time permits evaluation of the mechanical condition of the pump.

To identify sources of noise and vibration, the peaks of the measured frequency spectra are correlated with data pertaining to the possible vibration source components in the machine.

Fluid film bearings, such as journal bearings, are susceptible to oil whirl.

This phenomenon is a

design-induced machine force for which vibration amplitudes are detectable at frequencies of 0.43-0.47 of the pump's running speed.

Since the IWC pumps, which are vertical line shaft

pumps, use rolling element bearings in the motor, they are not susceptible to oil whirl.

The instrumentation conforms with the requirements of Section XI, IWP (1/2 rotational speed).

In addition, the motor roller bearings utilized by the licensee do not exhibit failure modes at the lower frequencies, as discussed above.

Therefore, the staff agrees with the licensee in that it is not necessary for the instrumentation to be capable of identifying oil whirl at running speeds less than 7 Hz.

It would be an undue hardship to require the licensee to procure new vibration instrumentation for application to only one group of pumps in the inservice testing program without a significant benefit in the information obtained.

Imposition of the requirements for 1/3 running speed would not provide a compensating increase in the level of quality and safety in the monitoring of the pumps.

l The proposed alter native is authorized pursuant to 10 CFR 50.55a(a)(3)(ii) based on the determination that compliance with the specified requirements results in an undue hardship without a compensating increase in the level of quality and safety that would ensue if the Code requirements were imposed.

The alternative method provides adequate assurance of the operational readiness of the intake cooling water pumps.

2.2.4 Conclusion The staff concludes that the relief request evaluated in this SE will provide reasonable assurance of the operational readiness for the applicable pumps to perform their safety-related functions.

The staff has determined that the proposed alternative is authorized by 10 CFR 50.55a (a)(3)(ii).

In making this determination, the staff has considered the burder, on the licensee if the Code requirements were imposed.

3 '

SUMMARY

OF ACTION ITEM RESPONSES TO SE TER SECTION 5.0 The NRC issued an SE for the Turkey Point Nuclear Power Plant, Units 3 and 4, IST Program on October 27, 1994.

The SE adopted the evaluations and recommendations in a Technical Evaluation Report (TER) prepared by Brookhaven National Laboratory.

Section 5 of the TER included a number of action items for the licensee to address.

In its letter of October 26,

1995, the licensee

informed the NRC of its actions taken regarding each of the items.

The table below summarizes the items and the actions taken.

No further NRC review is necessary, but the actions may be reviewed in detail during inspection activities.

TER Section 5.1 5.1.A 5.1. B 5.1.B 5.1.B 5.1. B Descri tion of Issue Pumps and valves in the Component Cooling Water, Residual Heat Removal, and Safety Injection Systems showed some noncompliance with Code Relief valve RV-3-747A&B not in IST program Verify no Category A

isolation valves from component cooling water s stem Review valve RCV-3-609 for inclusion in IST program Review control valve TCV-3-144 for inclusion in the IST program Review check valve 3-0717 for inclusion in the IST program Licensee's Res onse Two additional CVCS values RV-3(4)-0382 added.

Two RV-4-1451AKB valves from diesel generator cooling water expansion tanks are deleted Does not impact function to achieve or maintain safe shutdown conditions or miti ate an accident Does not impact function to achieve or maintain safe shutdown conditions or miti ate an accident Does not impact function to achieve or maintain safe shutdown conditions or miti ate an accident Does not impact function to achieve or maintain safe shutdown conditions or miti ate an accident Does not impact function to achieve or maintain safe shutdown conditions or miti ate an accident NRC Action Subject to inspection Subject to inspection Subject to inspection Subject to inspection Subject to inspection Subject to inspection 5.1.C 5.1.D Review butterfly valve Now included in the IST HCV-3-0758 for inclusion in program the IST ro ram Revise check valve 3-0875C Check valve 3-0875C has from Category C to Category been revised to Category A C A C Subject to inspection None 5.1.D 5.2 Review check valves 3-0875D,E,F as pressure isolation valves In relief request PR-4, proceduralize so accuracy of gauge meets Code Not listed in TS and have no specific leakage limit.

IST program categorizes as Category C as GL 89-04, Position 4 recommends Revised PR-4 and resubmitted for approval None Approved relief request PR-4.

TER Section Descri tion of Issue Licensee's Res onse NRC Action 5.3 Relief request PR-2 should PR-2 revised to indicate indicate vibration is being that vibration testing is measured uarterl bein measured uarterl Subject to inspection 5.4 5.4 5.4 5.4 Relief request VR-2 could be converted into a

deferral

'ustification Should check valves 3-0876A 8

C be in VR-2 Should valves 3-0876D,E perform an exercise close test Determine if seat leakage testing in the TS meets Code Withdrawn VR-2 and submitted refueling outage

'ustification Valves 3/4-0876A,B,C are alread in CSJ-SI-5,6 Added refueling outage justification to perform exercise test Testing meets Code OM-10 Subject to inspection None None None 5.5 Revise CSJ-RH-1 to discuss Revised CSJ-RH-1 to discuss impracticality of verifying impracticality of verifying closure of valves uarterly closure of valves uarterly None 5.5 5.5 5.5 5.5 5.5 5.6 5.6 Revise CSJ-SI-1 to discuss impracticality to testing durin ower o eration In CSJ-SI-2 verify safety function to o en In CSJ-SI-3 verify safety function to o en Revise CSJ-SI-5,6,7 for clarification Revise CSJ-AF-1 to show impracticality Revise ROJ-SA-1 to provide justification Verify if seat leakage testing is being performed for ROJ-CV-2,4 Revised CSJ-SI-1 No safety function in open osition No safety function in open osition Revised CSJ-SI-5,6,7 from fre uenc cate or 7 to 2

Enhanced deferral to demonstrate impracticality of testin valves uarterl ROJ-SA-1 has been updated to meet NUREG-1482 Updated IST program to reflect seat leakage testin None Subject to ins ection Subject to ins ection Subject to ins ection Approved Deferral Subject to ins ection None 5.6 Verify all 6 criteria in GL Revised ROJ-SI-5,6 to 89-04, Position 1 are address all 6 criteria in addressed GL 89-04, Position 1

None CSJ - Co S ut own Just>

>cat>on ROJ

- Refueling Outage Justification

4. 0 CONCLUSION The staff concludes that the relief requests as evaluated by this SE will not compromise the reasonable assurance of operational readiness of the pumps and valves in question to perform their safety-related functions.

The revised relief requests, PR-4 and PR-5, have been determined acceptable as discussed

in the above evaluations.

The licensee's actions taken to address issues and concerns identified in the NRC staff's SE (dated October 27, 1994) are adequate.

In addition, the staff noted that the licensee revised Relief Request PR-2 to indicate that pump vibration is being measured quarterly, as recommended in the October 1994 SE.

Therefore, the revised Relief Request PR-2 is accepted with no further NRC action required.

The revisions made to the IST Program that were not in response to the October 1994 SE do not impact previously-reviewed relief requests, but are subject to NRC inspection.

The staff has determined that approval of Relief Requests PR-4 and PR-5 is authorized pursuant to 10 CFR 50.55a(a)(3)(i) and (a)(3)(ii), respectively.

In making this determination, the staff has considered the impracticality of performing the required testing and the burden on the licensee if the requirements were imposed.

Principal Contributor:

Meena K; Khanna, EMEB/NRR October 22, 1996

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