ML20151H311

Concludes That Interpretation of ASME Code Which Allows 1.0 Error in MSIV Closure Time Poses No Safety Concern for Plants W/Tech Spec Min Allowable MSIV Closure Time of 3.0 or Greater

ML20151H311
Person / Time
Site:	Fermi
Issue date:	01/12/1983
From:	Eisenhut D Office of Nuclear Reactor Regulation
To:	Spessard R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML20151H314	List: ML20151H311 ML20154L339 ML20154L396 ML20154L426
References
NUDOCS 8301280399
Download: ML20151H311 (5)

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JAll1? IWO E MORAN0tlH FOR: Richard $oessard Otrector Otvision of Engineering 4 l Technical Programs l Region !!!, NRC -

l Fp0H: Darrell G. Eisenhut, Of rector i 01 vision of Licensing. NRR Suk1ECT: STOPWATCHE5 CALIBRATION AND A5ME REQUIREMENTS OW TRANSIENTS ANALY$($

la your letter of Septeder 7,1962, you requested NRR assistance to evaluate the ese of uncalibrated timing devices in safety-related applications and to clartfy an apparent inconsistency between transient analyses and A5ME reoutrements regarding valve closure times which are defined in the Technical specifications. Our Reactor Systems Branch evaluated the main steam isolation valves (MSIV) closure, and its impact on ninteum critical power retto (MCPR) at determined in the FSAR analyses.

Our Procedure and Test Review Branch provided the requirements for the stopwatches.

This review was performed pursuant to TIA S2-58.

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' The ASME code allows rounding of measured closure times for Ms1V's to the nearest 1.0 second of the use of a t' sing device with an accuracy of 1.0 second. This makes it possible for a measured closing time of 2.0 seconds to appear as 3.0 seconds which would satisfy the alloweble technical spectf tcation value and the F5AR analyses.

We evaluated the impact of a 1.0 second closure time versus a 4.0 second closure time on vessel pressure and MCPR for the M51V closure event. In the analysis, an MSIV position switch scram was assumed for the effect on MCPR and a high flux screm was assumed for the assessment of the effect on overpressure protection.

The results of these analyses indicate that for closure times of 2.0 seconds or greater, the impact on MCPR and vessel pressure is instinificant and will not challenge safety limits. For the limiting cases, vessel done cressure was calcu-1sted to increase 170 psi and the MC9R was esiculated to be four percent of the initial MCPR valve. For a typical botilng water reactor operating at 1100 psin and an initial EPR of 1.24, this results in a peak vessel pressure (bottoa of I pressere) of less than 1300 psti and a MCPR nF i.19. The respective safety ilmits aret oressure must he less than 13M psig and TPP aust be areater tren \ fif 1.06 On this bests, we conclude that the Interpretation of the A5ME code etch 'I allow as much as 1.0 second errnr in MlV closure time is of no safety cr.ncern for plants with a technical spectf tcation minte allowable Mlv closure time of jM,'

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Richard Spessard ,

! 'Jith resoect to the use of stopwatches for measur-aent of tine intervals for validating coerability of safety-related equipment, this method is acceptable where it can be shown that this method of measurement provides the required I accuracy. Therefore, the results of the above analyses indicates that a 1.0 second total deviation on NSIV closure time is acceptable. The storwatches j must be calibrated and controlled as required by 10 CFR Part 50, Appendix R.

Article X11, and the the required accuracy is determined from the technical j specification bases. ANS!/ANS-58.41979, "American National Standard Criteria

for Technical Specifications for Nuclear Power Plants," paragraoh 5.1.(6) states

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) " Errors, from instrumentation or other sources, assuned in the I develorment of the technical specification limits shall he dis-cussed in the bases to provide a clear relationship between the technical specification and the safe'v analysis values.'

que technical specification basis does not provide a discussion of measurement errne, and the limit does not include an allowance for measurement error. It is necessary to include a measurement error allowance in the surveillance test I

acceptance criteria.

For the operator error comoonent of the error associated with the use of stop-watches, we consider 700 milliseconds to be an acceptable assunntion. ,

! We trust that the information orovided is responsive to your concern, and the  !

. WRR responsthilities under TI A No. A?-58 have been comoleted. '

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Origina1 ntaned tri I

I Darrell G risenhut, Director l Oivision of Licensinq

! Of fice of Huclear Reactr Gaqui stion ec: R. Starotter.ki, 0-I l J. 015hinski, 0-!!

J. Caq11 aron, P-tv J. Crews, 0-v i

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XI.7742 4 .

Inteepretation: XI-7742

Subject:

Section XI, Division 1. Subsection IWV Date luued: February 18,1977 .

File: BC 76 433 '

Question 1: The reactor coolant pressure boundary extends to the second valve. These are two check valves in series, two manual valves, two auto isolation valves, and the pressurizer pressure control valve backed up by a remote manual isolation valve. Is it the intention of I%V.3420 to measure leakage of each of these valves including the pressurizer pressure control valve and safety relief valves?

j Reply 1: In accordance with Subarticles IwV 1100 and 1%V 1300, all Code Classes I,2, and 3 valves as stated therein must be tested. The intent of the Code is to test all valves required to be in operational I readiness.

Question 2: Reg. Guide 1.26, page 1.26-2 footnote implies that check valves on all influent lines do not have high leaktight integrity and that with additional valve with high leaktight integrity the line can be classified as group D. It is likely that RCPB check valve leakage will exceed leakages allowed in IWV 3420 Table I and may cause costly shutdown time for repairs. These valves are not isolatable from the primary coolant loops for testing or repair, is it permissible to avoid testing these check valves and extend the RCPB to the next leaktight valve for category A leakage measurement?

Reply 2: Same as Reply 1.

Question 3: 1%Y-3420 allows testing using pressure differentials less than the functional pressure.

Will you provide a formula that can be used to interpret the paragraph?

Reply 3: In accordance with paragraph 1%V 3420(c)(5), the adjusted leakage equals observed leakage times (function pressure over test pressure)sia, Question 4:

Is it the intent of Section XI to include all containment isolation valves or only those lines Classed 2 or 3 that extend beyond the containment boundary?

Reply 4: Same as Reply 1.

Question 5: If containment boundary valves are tested according to Appendix J,is it the intent to also test these valves in acccrdance with Section XI?

l Reply 5: Yes. Specific permissible leakage rates for individual valves are required to be determined by the plant owner in accordance with IWV 3420(f).~ '

Question 6: Does Sectiora XI accept reasons, such as high temperatures, airborne activity, lack of complete visibility of masks, and lack of oxygen, for not performing tests on valves inside containment dur.

ing operation ifit is necessary to enter in order to perform the test?

Reply 6: No.

Question 7:

(a) Does a manual valve used for containment boundary fallinto Category A and require leak testing?

(b) Does a check valve on the discharge of a pump require functional testing?

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8 XB 7742, XI 7743, XI 7744 (c) Can sample line (~ 3/8 in.) remote operated valves be excluded?

(d) Can test lines with remote operated valves be excluded since they are not directly related to operation?

Reply 7: Same as Reply 1.

Question 8: Since specific maximum leakage for individual valves are not listed in technical specifica-tions should they be disregarded altogether? If not please provide examples.

Reply 8: Specific individual leak rates shall not be disregarded. Specific permissible leakage rates for individual valves are required to be determined by the plant owner in accordance with IWV 3420(f).

Question 9: Does IWPinclude turbine driven auxiliary feedwater pumps or only motor driven pumps?

Reply 9: Determination of whether turbine driven auxiliary feedwater pumps is included in the scope of IWP is contained in the words of I%P-1100,". . . are provided with an emergency power source." The type of driver is not a consideration.

Interpretation: XI 77 04

Subject:

Section XI, Division 1, Article IWP-1000 Date issued: March 21,1977 File: BC 76-669 Question: What kind ofinstrumentation should be procured and used by the owner of the power plant in order to conduct the periodic inservice testing of pumps to measure the differential pressure and bearing temperature?

Reply: Instruments that satisfy the requirements of Article IWP-4000 may be used to measure differential pressure and bearing temperature.

1 Interpretation: XIt7918

Subject:

Section XI, Dmsion 1. Testing inaccessible Vahes.1% V.3300 i Date issued: December 12,1979 l

l File: BC 79130 Question:

Is it the intent of Section XI, Dmsion I to require that those valves which are accessible be directly observed at each valve exercising to confirm that remote valve indications accurately reflect valve operations?

Reply: It is the intent of Section XI, Dnision I to require that all valves, accessible and inaccessible, that have remote valve indicators be visually checked at least once every 2 years to verify that remote valve indications accurately reflect valve operation.

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,e Mi-17919, XI 1-7HO Interpretation: XI l-7919

Subject:

Section XI, Division 1.Operabihty limits of Pumps,1%? 3210 Date issued: December 12,1979 File: BC-79150 Question: 1%7 3210 of the 1977 Edition of Section XI, Division I states that "In the event these ranges (specified in Table IWP-3100 2 for the differential pressure across pump) can not be met, the Owner shall specify in the pump record the reduced range hmits to allow the pump to fulfill its function in lieu of the ranges given in Table IWP 3100-2" Do the Alert Ranges specified in Table I%P 3100-2 refer to pump test data that falls outside the specified range,or does it refer to a system analysis which may indicate that the required Action Range be less restrictive than those ranges specified in the Table?

Reply: 1%7 3210 refers to Table IWP 3100-2 which specifies three ranges - Acceptable Range, Allowable Range,and Required Action Range The hmins within each of these ranges refers to the pump and not to the system,that is, the ranges are for the pump test data. If these ranges cannot be met, the Owner can specify new range hmits (e.g., from a range of 0.93 to 1.02 to a range of 0 89 to 1.03 for AP).

Using the less conservative ranges the Owner shall show that the overall pump performance has not degrad-ed from its intended function.

O Interpeetation: XI8101

Subject:

Section XI, Division 1,IWY 2200(a) Categorization of Containment Isolation Valves Date Issued: April 17,1981 File: BC 819 Question: Is it the intent of Section XI, Division I that Category A as defined in IWV 2200(a),1977 Edition, Summer 1978 Addenda, applies to containment isolation valves ordy,or is this definition intended to be applied to pressure isolation valves?

Reply: IWV 2200(a) defines Category A valves.The definition applies to the use of the valve by the Owner,not the type of valve involved. If an Owner requires that containment isolation valve leakage is to be limited to a specific amount, then by definition, containment isolation valves would be classified as

Category A This would also apply to pressure isolation valves,1f the Owner specifies a specific limit to the amount ofleakage of that valve.

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