ML20058J006

Proposed Tech Specs Re Turbine Overspeed Protection

ML20058J006
Person / Time
Site:	Vogtle
Issue date:	11/19/1993
From:	GEORGIA POWER CO.
To:
Shared Package
ML19311B229	List: ML20058H997 ML20058J006 ML20058J010
References
NUDOCS 9312130332
Download: ML20058J006 (11)

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-l ENCLOSURE 3  ;

i VOGTLE ELECTRIC GENERATING PLANT j REQUEST TO REVISE TECIINICAL SPECIFICATIONS RELATED TO TURBINE OVERSPEED PROTECTION l PROPOSED CIIANGE TO TIIE TECIINICAL SPECIFICATIONS 1

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• PDR ADOCK 05000424 U P' PDR [$  ;

INSTRUMENTATION 3/4.3.4 TUR OVERSPEED PROTECTION M MITING CONDITION FOR OPERATION [

3.3 4 At least one Turbine Overspeed Protection System shall be OPERABLE.

ILITY: MODES 1, 2*, and 3*.

APPLI

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ACTION: \ [

a. Wi one stop valve or one control valve per high pressure rbine ste' line inoperable and/or with one reheat stop valve , one rehea intercept valve per low pressure turbine steam l'he inoperable, restor gthe inoperable valve (s) to OPERABLE status wi in 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, or clo(se at least one valve in the affected steam lj es, or isolate the turb1 e from the steam supply within the next hours.

b. With the ab e required Turbine Overspeed Prot tion System otherwise inoperable, w' thin 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> isolate the turbi from the steam supply.

SURVEILLANCE REQUIREMENTS 9.3.4.1 The provisions of Sp c fication 4.0 4 re not applicable.

4.3.4.2 The above required Turbin ;Oversp e Protection System shall be demonstrated OPERABLE:

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a. At least once per 7 days whi Ni n MODE 1 and while in MODE 2 with the l turbine operating, by cycli e h of the following valves through at least one complete cycle f om th running position:

1) Four high pressure turbine stop valves, i

2) Six low pressur turbine intermed te stop valves, and l

3) Six low press e turbine intercept v lves. l

b. At least once p 31 days while in MODE 1 an while in MODE 2 with the turbine o rating, by direct observation the movement of each of the above alves and the four high pressure ,rbine control valves,  ;

through on complete cycle from the running posit' n,

c. At leas once per 18 months by performance of a CHAN ' ' CALIBRATION on th urbine Overspeed Protection Systems, and i

d. At east once per 60 months by disassembling each of the ve valves (i cluding the four high pressure turbine control valves) a performing visual and surface inspection of valve seats, disks and ste and ferifying no unacceptable flaws or corrosion.

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• No applicable in MODE 2 or 3 with all main steam line isolation valves and i sociated bypass valves in the closed position and all other steam flow paths 1 (otheturbineisolated. k ,

V0GTLE UNITS - 1 & 2 3/4 3-73 Amendment No. M(Unit 1)

Amendment No. p (Unit 2) i

. . . . c INSTRUMENTATION ,

BASES 3/4.3.3.10 EXPLOSIVE GAS MONITORING INSTRUMENTATION This instrumentation includes provisions for monitoring (and controlling).

the concentrations of potentially explosive gas mixtures in the GASEOUS WASTE  !

PROCESSING SYSTEM. The OPERABILITY and use of this instrumentation is consis- )

tent with the requirements of General Design Criteria 60 and 63 of Appendix A I to 10 CFR Part 50.  ;

1 3/4.3.3.11 HIGH ENERGY LINE BREAK ISOLATION SENSORS

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l The operability of the high energy line break isolation sensors ensures  ;

that the capability is available to promptly detect and initiate protective - '1 action in the event of a line break. This capability is required to prevent l damage to safety-related systems and structures in the auxiliary building. )

i 3/4.3.4 TURBINE OVERSPEED PROTECTION (oe te+ed) 1 inis specifTC1tibn is provided to ensure that the turbine p ef^^d -

protec .v.."actrumentation and the turbine speed c ' raive,s are OPERABLE and will protec rspeed. Protection from' turbine rbine from excessive overspeed- h1 n s. J,aca.gxcessive overspeed of the turbine could generate gy +T$F damaging missiles whichTotf%u= met a d damage safety-

_-g r tomponents, equipment or structures. -

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V0GTLE UNITS - 1 & 2 B 3/4 3-6 Amendment No. 55 (Unit 1)

Amendment No. 34 (Unit 2) i I

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, -ENCLOSURE 4 VOGTLE ELECTRIC GENERATING PLANT l REQUEST TO REVISE TECHNICAL SPECIFICATIONS RELATED TO TURBINE OVERSPEED PROTECTION

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PROPOSED CHANGE TO THE FSAR in conjunction with the relocation of requirements for the turbine overspeed protection system to the FSAR, Georgia Power Company is proposing to revise the test intervals for the high pressure turbine stop and control valves and the low pressure turbine intermediate stop valves and intercept valves. In January 1984, the General Electric (GE) Company produced the proprietary report entitled " Probability of Missile Generation in General Electric Nuclear Turbines." Since approval of this methodology by the NRC in 1986 (reference NUREG-1048, Supplement 6, Appendix U), it has been routinely applied to establish reinspection intervals for low pressure (LP) .

turbine rotors with shrunk-on wheels and to furnish unit-specific wheel missile probabilities to the involved utility owners. Unit-specific wheel missile probabilities are affected, in part, by the reliability of the turbine overspeed protection system. In addressing the reliability of the turbine overspeed protection system, the Janua:y 1984 report used available valve failure-to-close data, and the resulting recommended nuclear steam valve surveillance test intervals were weekly for the stop valves, monthly for the control valves, and weekly for the intermediate stop and intercept valves (weekly / monthly / weekly, or WMW).

Since this time, steam valve surveillance testing has been linked by utility owners to unplanned -

reactor irips and corresponding unit unavailability. In 1991, a study was initiated by the BWR ,

Owners Group, with the participation of GE, to evaluate the potential for extending turbine valve surveillance test intervals as a means for reducing unplanned reactor scrams and increasing unit availability. In conjunction with this study, GE augmented their nuclear database with recent nuclear steam valve failure-to-close data, and this recent data was incorporated into the wheel missile analysis. The study demonstrated that within specific limits and depending on unit specific ,

characteristics, flexibility with regard to steam valve surveillance testing is possible while maintaining wheel missile probabilities within limits. Other than the updated steam valve failure-to-close data, this supplemental study does not involve any fundamental changes to the method i' described in the 1984 report.

The turbines at VEGP are unfavorably oriented. Therefore, the limit for the probability of wheel missile generation is 10-5 per year based on NUREG-1048. Georgia Power Company proposes to optimize the test intervals for cycling the high pressure turbine stop and control valves and the low pressure turbine intermediate stop valves and intercept valves by routinely evaluating the effects of three sets of valve test intervals on wheel missile generation probabilities afler each low .

pressure turbine rotor inspection. These test intervals would be weekly / monthly / weekly (WMW),

monthly / quarterly / monthly (MQM), and quarterly / quarterly / quarterly (QQQ) as follows:

- WMW:

Weekly Testing - Stop Valves I Monthly Testing - Control Valves Weekly Testing - Intermediate Stop and Intercept Valves E4-1 4

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ENCLOSURE 4 (CONTINUED)

VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECHNICAL SPECIFICATIONS RELATED TO TURBINE OVERSPEED PROTECTION PROPOSED CHANGE TO THE FSAR

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MQM:

Monthly Testing - Stop Valves Quarterly Testing - Control Valves Monthly Testing - Intermediate Stop and Intercept Valves QQQ:

Quarterly Testing - Stop Valves Quarterly Testing - Control Valves Quarterly Testing - Intermediate Stop and Intercept Valves The valve test interval chosen for the next rotor inspection period would be based on maintaining the missile generation probability less than 10-5per year. While these standard test intervals have been selected for routine evaluation, other test schedules may also be evaluated on a case-by-case basis within the bounds of a maximum three-month interval. Note also that the results of the study indicated that exchanging the valve test intervals between the main stop and control valves has no significant effect on the resulting turbine overspeed and wheel missile probabilities. For example, a weekly / monthly / weekly schedule is equivalent to a monthly / weekly / weekly schedule from the standpoint of wheel missile probabilities.

As an example, GE used this methodology with the last low pressure tui .ine rotor inspection results for both units (not including the most recent inspection performed on Unit 2 during the outage which ended October 20,1993). The following tables present the results of those calculations:

Unit I Wheel Missile Probability 6.0 Years From Inspection Rotor WMW MQM QQQ LPA 1.8E-07 1.9E-06 6.6E-06 LPB 1.6E-07 1.7E-06 5.8E-06 j 6.1E-06 LPC 1.7E-07 1.8E-06 TOTALS l 5.lE-07 l 5.4E-06 l 1.85E-05 h

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ENCLOSURE 4 (CONTINUED) i VOGTLE ELECTRIC GENERATING PLANT REQUEST TO REVISE TECIINICAL SPECIFICATIONS -

RELATED TO TURBINE OVERSPEED PROTECTION PROPOSED CHANGE TO TIIE FSAR I Unit 2 Wheel Missile Probability 6.0 Years From Inspection Rotor WMW MQM QQQ ^

LPA 2.2E-07 2.3 E-06 8.lE-06 LPB 2.lE-07 2.lE-06 7.5E-06 LPC 2.2E-07 2.3E-06 8.0E-06  !

TOTALS l 6.5E-07 l 6.7E-06 l 2.36E-05

- Based on these results, the maximum valve test intervals to ensure that the wheel missile generation probability is below 10-5 would be MQM.

Marked-up pages showing the proposed changes to section 16.3 of the FSAR follow this i enclosure. In addition, a proprietary version (GET-8039) and nonproprietary version (GET-8039.1) of the Supplementary Report: Steam Valve Surveillance Test Interval Extension, September 1993 are included as pan of this enclosure. The supplementary report provides the ,

detailed methodology supporting this proposed change to the VEGP FSAR. i

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l VEGP-FSAR-16 The reactor vessel material irradiation surveillance l specimens shall be removed and examined to determine changes i in material properties as required by 10 CFR Part 50,

• Appendix H in accordance with the schedule in FSAR table  :

16.3-3. The results of these examinations shall be used to update Technical Specification figures 3.4-2 and 3.4-3.

Requirement 5 - Containment Isolation Valves '

Containment isolation valves required to be operable by Technical Specification 3.6.3 shall be demonstrated operable with isolation times as shown in FSAR. table 16.3-4. j

• Requirement 6 - Containment Penetration Conductor Overcurrent Protection  ;

-l The containment penetration conductor overcurrent protec ive I devices required by Technical Specification 3.8.4.1 shall be as shown in table 16.3-5.  !

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l INSERT FOR FSAR PAGE 16.3.1-2 .

Requirement 7 - Turbine Overspeed Protection At least one Turbine Overspeed Protection System shall be OPERABLE in MODES 1,2, and 3.

This requirement is not applicable in MODES 2 and 3 with all main steam isolation valves and associated bypass valves in the closed position and all other steam flow paths to the turbine isolated.

With one stop valve or one control valve per high pressure turbine steam line inoperable and/or one reheat intercept valve per low pressure steam line inoperable, restore the inoperable valve (s) to OPERABLE status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, or close at least one valve in the affected steam lines, or isolate the turbine from the steam supply within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

With the above required Turbine Overspeed Protection System otherwise inoperable, within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> isolate the turbine from the steam supply.

The above required Turbine Overspeed Protection System shall be demonstrated OPERABLE:

a. By cycling each of the following valves through at least one complete cycle from the running position while in MODES I and 2:

1. Four high pressure turbine stop valves,

2. Six low pressure turbine intermediate stop valves,

3. Six low pressure turbine intercept valves, and

4. Four high pressure turbine control valves.

The test intervals for the above valves will be determined in accordance with the supplement to the January 1984 General Electric report to the NRC entitled " Probability of Missile Generation in General Electric Nuclear Turbines Supplementary Report: Steam ,

Valve Surveillance Test Interval Extension," GET-8039, September 1993. The valve testing schedule as determined by the above methodology will be maintained for the total period between any two low pressure turbine rotorinspections. The surveillance that involves cycling the four high pressure turbine control valves (as well as the other valves) will include direct observation of the movement of each of the above valves.

b. At least once per 18 months by performance of a CHANNEL CALIBRATION on the Turbine Overspeed Protection Systems, and

c. At least once per 60 months by disassembling each of the above valves (including the four high pressure turbine control valves) and performing a visual and surface inspection of l valve seats, disks and stems and verifying no unacceptable flaws or corrosion.

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GENERAL ELECTRIC COMPANY AFFIDAVIT

1. RONALD J. PLACEK, being duly sworn, depose and state a.s follows:

(1) I am Manager, Service Engineering, GE Industrial & Power Systems, General Electric -

Company ("GE") and have been delegated the function of reviewing the infonnation described in paragraph (2) which is sought to be withheld, and have been authorized to apply  ;

for its withholding.

(2) The infonnation sought to be withheld is contained in the GE proprietary report GET-8039,

" Probability of Missile Generation in General Electric Nuclear Turbines Supplementary Report: Steam Valve Surveillance Test Interval Extension" , dated Septeinber 1993.

Specifically, the proprietary information is contained in Figures 2-1,2-2 and 2-3 of GET-8039. These proprietary figu. s are individually marked in the report as PROPRIETARY INFORMATION GENERAL ELECTRIC COMPANY.

(3) In making this application for withholding of proprietary information of which it is the owner, GE relies upon the exemption from disclosure set forth in the Freedom of Information Act ("FOIA"), 5 USC Sec. 552 (b) (4), and the Trade Secrets Act,18 USC Sec.1905, and NRC regulations 10 CFR 9.17 (a) (4), 2.790 (a) (4), and 2.790 (d) (1) for " trade secrets and commercial or financial infonnation obtained from a person and privileged or confidential" (Exemption 4). The material for which exemption from disclosure is here sought is all

" confidential commercial information", and some portions also qualify under the narrower-det~mition of " trade secret", within the meanings assigned to those terms for purposes of FOIA Exemption 4 in, respectively, Critical Mass' Energy Proiect v Nuclear Reculatory Commission. 975F2d871 (DC Cir.1992), and Public Citizen Health Research Group v. FDA, 704F2d1280 (DC Cir.1983),

(4) Some examples of categories of information which 01 into the definition of proprietary _

information are:

a. Infonnation that discloses a process, method, or apparatus, including supporting data and analyses, where prevention of its use by General Electric's competitors without license from General Electric constitutes a competitive economic advantage over -

other companies;

b. Information which, if used by a competitor, would reduce his expenditure of resources or improve his competitive position in the design, manufacture, shipment, installation, assurance of quality, or licensing of a similar product;

c. Information which reveals cost or price information, production capacities, budget levels, or commercial strategies of General Electric, its customers, or its suppliers;

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d. Information which reveals aspects of past, present, or future General Electric  !

customer funded development plans and programs, of potential commercial value to General Electric;

e. Information which discloses patentable subject matter for which it may be desirable to obtain patent protection.

The information sought to be withheld is considered to be proprietary for the reasons set forth in both paragraphs (4)a. and (4)b., above.

(5) The information sought to be withheld is being submitted to NRC in confidence. The information is of a sort customarily held in confidence by GE, and is in fact so held. Its  !

initial designation as proprietary information, and the subsequent steps taken to prevent its l unauthorized disclosure, are as set forth in (6) and (7) following. The information sought to  ;

be withheld has, to the best of my knowledge and belief, consistently been held in confidence by GE, no public disclosure has been made, and it is not available in public sources. All  !

disclosures to third parties including any required transmittals to NRC, have been made, or i must be made, pursuant to regulatory provisions or proprietary agreements which provide for '

maintenance of the information in confidence.

(6) Initial approval of proprietary treatment of a document is made by the manager of.the originating component, the person most likely to be acquainted with the value and sensitivity  ;

of the information in relation to industry knowledge. Access to such documents within GE is limited to a "need to know" basis.

e (7) The procedure for approval of external release of such a document typicJy requires review by the staff manager, project manager, principal scientist or equivalent authority, by the manager of the cognizant marketing function (or his delegate), and by the Legal Operation, for technical content, competitive effect, and determination of the accuracy of the proprietary l designation. Disclosures outside GE are limited to regulatory bodies, customers, and  ;

potential customers, and their agents, suppliers, and licensees, and others with a legitimate need for the information, and then only in accordance with appropriate regulatory provisions or proprietary agreements. ,

(8) The infonnation identified in paragraph (2) is classified as proprietary because it contains generic performance data which are specifically applicable to equipment and systems supplied by GE. In addition, it contains generic analysis results obtained by applying the proprietary GE turbire wheel missile analysis which forms the basis for the current submittal to the NRC. This analysis was developed by GE and submitted to the NRC in a proprietary 1984 report entitled " Probability of Missile Generation in Geneml Electric Nuclear Turbines".

Since its approval by the NRC in 1986 (reference NUREG-1048, Appendix U), the analysis l has been applied exclusively by GE. The probabilistic wheel missile analysis provides GE with a unique methodology which supports GE's in-service wheel inspection program, provides a basis for supplying customers with recommendations on equipment inspection, ,

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GENERAL ELECTRIC COMPANY testing and operational requirements, and supports discussions and negotiations on turbine rotor / wheel repair and replacement options.

Development of the involved equipment and associated perfonnance data, and of the turbine wheel missile analysis including the analysis methods, data and computer programs, were achieved at a significant cost to GE, exceeding several million dollars. The availability of these data and analysis capabilities constitutes a major GE asset.

(9) Public disclosure of the information sought to be withheld is likely to cause substantial harm to the competitive position of the General Electric Company and deprive or reduce the availability of profit making opportunities. This infonnation is essential to GE to support ongoing product development, sales and service activities. The value of this information to GE would be substantially lost if the information were disclosed to the public. Making sucli information available to competitors without having been required to undenake similar expenditure of resources would unfairly provide competitors with a windfall, and deprive GE of the oppodunity to exercise its competitive advantage to seek an adequate return on the large investment involved.

STATE OF NEW YORK )

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COUNTY OF SCllENECTADY )

Ronald J. Placek, being duly sworn, deposes and says:

That he has read the foregoing affidavit and the matters stated therein are true and correct to the best of his knowledge, information, and belief.

Executed at Schenectady. New York, this day of de c. ,1993 s rf ffh Ronald J. Placel;6/

General Electric Company Subscribed and sworn before me this 3 ' day of od 1993 n f

'Y!G d4 [,.,J Notary Public, State of New York PATRICIA A. LEONARD Noenry Puusa, seats M New m Quellflod la Sarsloge Courity j'

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