ML17332A999

Proposed Tech Specs Adding Exemption to TS 4.0.4 in SR for MSIV

ML17332A999
Person / Time
Site:	Cook
Issue date:	10/20/1995
From:	INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:
Shared Package
ML17332A998	List: ML17332A997 ML17332A999
References
NUDOCS 9510310312
Download: ML17332A999 (34)

Text

ATTACHMENT 2 TO AEP'NRC'1213A EXISTING TECHNICAL SPECIFICATION PAGES MARKED TO REFLECT PROPOSED CHANGES 9510310312 951020 PDR ADOCK 05000315 P PDR

0 3 4.7 SYSTEMS 3 4 7. TGRBTNE CYCLE SAFETY VALVES NG CONDX TON FOR OPERA ON 3.7.1.1 All main steam line code safety valves associated with each steam generator shall be OPERABLE.

anc v~lu~is> a~

a. 4 With 4 reactor coolant loops and associate steam generators with one or more main steam 1 ne code safety valves in'perationpand inop'arable, operation , na proceed provide that within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, either the inoperable restored to OP lZ status'r the Power Range Neutron Flux High Setpoint trip is reduced.

per Table 3.7-1; otherwise, be in ae:-4e~ HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and .comply

~~ a@So %56cAAthA b.

b. (Wi 3 reactor coolant loops and associated steam generators in peration~ and with one or more main steam line code safety valves associated with an operating loop inoperable, operation 4MGMM nay proceed providedg that nirhin 4 honte, either the in'operable are opened; otherwise, be in ~

<~"+i~C ~~s.restored to OPERABLE status~ or the reactor trip breakers Hol-SHUTDOWN within the Next 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

C. The provisions of Specification 3.0.4 are not app1.$ cable.

SURVEXLLANCE RE UIREMENTS

'n4.7.1.1.

accordance 4.7-1.

Each main steam line code safety valve shall be demonstrated OPERABLE with Specification 4.0.5 and with lift settings as shown in Table The safety valve shall be reset to the nominal value ~1X whenever found outside the +1K tolerance.

q g ~tee~ i~

po,s-,~S Wk>M.

og 3

Sq~Q~O

~

COOK NUCLEAR PLANT - UNlT 1 3/4 7-1 ~HENT NO. k@0,464

'TABLE 3.7-l HAXlHUH ALLOWABLE POllER RAHGE NEUTRON FLUX lllGII SETPOIHT MITll IHOPERAOLE STEAH E PIE~I'IKTEEEEPEPEIEWIE Haximum Allowable Power Range

~

Haxinem tiumber of Inoperable Safety tleutron Flux iligh Setpoint Valves on An O eratin Steam Generator Percent of RATED THERHAL POWER 4 I

~ ~

/4 1 V V<

The OPERABILITY of the main steam line code safety valves ensures chat the secondary system pressure will be limited co wt.thin i.cs design pressure of 1085 psig during the most severe anticipated system opera-tional cransient. The maximum relievt.ng capacity is associated wich a curbine trip from 100% RATED THER.fAL POMER coincident with an assumed loss of condenser heat sink (i.e., no sceam bypass co the condenser).

The specified valve li.ft settings and relieving capacities are in accordance with the requirements of Section III of che ASME Boi.ler and Pressure Code, 1971 Edition. The total relieving capacicy for all valves on a11 of the 'steam li.nes is 17,153,800 lbs/hr which is approximately 121 percent of the tocal secondary steam flow of 14,120,000 lbs/hr ac 100%

RATED THERMAL POMER. A minimum of 2 OPERABLE safecy valves per operabLe steam generator ensures that sufficient relievt.ng capacity i.s available for che allo~able THER.'iAL POWER restri.ction in Table 3.7-1.

STARTUP and/or POMER OPERATION is allowable with safety aalves inoperable within the limitations of the ACTION requiremencs on the basis of che reduction in secondary system steam flow and THLq.KL POt:ER required by the reduced reactor trip seccings of the Power Range Neutron Flux channels. The reactor trip setpoinc reductions are derived on the .

following bases:

For 4 loop operaci.on Qplam..

SP x (109) a.Harkr 8

'X

%here:

SP reduced reacc trip setpoin j.n percenc of RATED THERMAL POP ER V maximum number of in able safecy val.ves per sceam line <<

1, 2 or 3.

X - Total reli.ev'ng capacity of al safecy valves per steam line 4 8,450 lbs/hour.

Y Nax um relieving capacity of any one s ecy valve 57,690 lbs/hour.

(10 Power Range Neutron Flux-High Trip Secpoinc for loop operaci.on.

D. C. COOK - UNIT 1 B 3/4 7-1 AHENDHENT NO. 120

Re lacement text for 3/4.7.1.1 Bases Hi<5 =(100/Q)

(4wpg Z

where:

Hi C = Safety Analysis power range high neutron flux setpoint in percent Q = Nominal NSSS power rating of the plant (including reactor coolant pump heat) in Mwt K = Conversion factor, 947.82Q3tu/~Sec Mwt w, = Minimum total stcam flow rate capability of the operable MSSVs on any one steam generator at the highest MSSV opening pressure including tolerance and accumulation, as appropriate, in lb/sec. For example, if the maximum number of inoperable MSSVs on any one steam generator is one, then w, should be a summation of the capacity of the operable MSSVs at the highest operable MSSV operating pressure, excluding the highest capacity MSSV. Ifthe maximum number of inoperable MSSVs per steam generator is three, then w, should be a summation of the capacity of the operable MSSVs at the highest operable MSSV operating pressure, excluding the three highest capacity MSSVs.

h,, = Heat of vaporization for steam at the highest MSSV opening pressure including tolerance and accumulation, as appropriate in Btu/ibm 4 = Number of loops in plant The values calculated from this algorithm are then adjusted lower for use in Technical Specification 3.7.1.1 to account for instrument and channel uncertainties by 9%. This reduces the maximum plant operating power level so that it is lower than the reactor protection system setpoint by an appropriate operating margin.

3 4 . 7 PLANT SYSTEMS 3 4.7.1 XNE CYCLE S F VALVES NG COND ON FO OPERA ON 3.7.1.1 All nsdn stean line code safety valves ssscclated vdeh each stean generator shall be OPERABLE.

APPLXCABXLX Y: Modes 1, 2 and 3.

~OTXON: o~

moog'.CZ: Valve@

a. Wi.th 4 reactor coolant loops and associate steam generators in operation and with one or more main steam 1 ne code safety valves inoperablL, operation ma proceed providedg that within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, either the inoperable restored to OP LE status> or the Power Range Neutron Flux High 'ip etpoint 's reduced per Table 3.7-1; otherwise, be in ae-~~ HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and . Complot, 40~ clog~ ~4~ta4 S.

b. 4Wi 3 reactor coolant loops and associated steam generators in with one or more main steam line code safety valves associated with an operating loop inoperable, operation ~BOY

'perationyand I

may proceed providedg that within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, either the'noperable V<QclS)oVC ~o-ke restored to OPERABLE status/or the reactor trip breakers are opened; otherwise, be in CGA SHUTDOWN within the'ext 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

HoT'-

The provisions'f Specification 3.0.4 are not applicable.

SURVEXLLANCE RE EMENTS 4.7.1..1 Each main steam line code safety valve shall be demonstrated OPERABLE in accordance with Specification 4.0.5 and with liftsettings as shown in Table 4.7-1. The safety valve shall be reset to the nominal value pl%whenever found outside the +1K tolerance.

~f ice P~g,sy~ gQ Q~>Q,~~ 9.0.9 o~ VO+ a PP4cab4 ~

~ ieiODE 3.

COOK NUCLEAR PLANT - UNIT .2 3/4 7-1 AMENDMENT NO. Sa,167

TABLE 3 -1 LLOWABLE OW NGE EU RON GH SETPOINT WIT INOPERABLE S E SAF VALVES DURING 4 LOOP OPERA 0 Maximum Allowable Power Range Maximum Number of Inoperable Safety Neutron Flux High Setpoint Valves o 0 e at n Steam Generator Percent o RATED ERMAL POWE COOK NUCLEAR PLANT - UNIT 2 3/CI. 7-2

3 4.7 PIANT SYSTEMS BASES 3 4.7.1 TURBINE CYCLE 3 4.7.1.1 SAFETY VALVES The OPERABILITY of the main steam line coda safety valves ensures chac the secondary system pressure vill be limited to vithin 110i of i,ts design pressure of 1085 psig during the most severe anticipated system operational czansient. Th>> maximum reueving'capacity is associated vith a cuzbine tzip from 100% RATED THERMAL POMER coincident vith an assumed loss of condensez heat sink (i.e., no steam bypass to the condenser).

The specified valve ltfc settings and relieving capacities are in accordance vith che requirements of Section III of the ASME Boiler and Pressure Code, 1971 Edition. The total relievtng capacity of all safety valves on all of the steam lines is 17,153,800 lbs/hr vhich is at least 105 percent of the maximum secondary steam flov rate at 100% RATED THERMAL POVER. h minimum of 2 OPERABLE safety valves per steam generator ensures that sufficient relieving capacity is available for che allovable THERMAL POVER restriction in Table 3.7-1.

STARTUP and/or POVKR OPERATION is allovable vich safety valves inoperable vithin the limitacions of the ACTION requirements on the basis of the reduction in secondary syscem steam flov and THERMAL POM requt.red by the reduced reactor trip settings of the Pover Range Neutron Flux channels. The reactor trip setpotnt reductions are derived on the folloving bases:

For 4 loop operation

@pe ~

Where:

a.~hah SP reduced reac tzip secpoint in per nt of RATED THECAL POVER V maximum number of inope ~ safety valves per steam line X total relievtn capacity of all s ty valves pez steam line in lb ours 4,2&8,450 Y max relieving capacity of any one safe alve lbs./hour 857,690 9 Pover Range Neutron Flux-High Trip Secpoint for 4 loop operation COOK NUCLEAR PLANT - UNIT 2 B 3/4 7-1 AMENDMENT NO. Sl. 134

Re lacement text for 3/4.7.1.1 Bases

~

Hil=(100/Q) (4)vh K

)

where:

Hi 4 = Safe@Analysis power range high neutron flux setpoint in percent Q = Nomaal NSSS power rating of the plant (including reactor coolant pump heat) in Mwt K = Contortion factor, 947.82 ~Bto/Sec Mwt w, = Mimmxm total steam flow rate capability of the operable MSSVs on any one steam generator at the highest MSSI'opening pressure including tolerance and accumulation, as appropriate, in Ib/sec. For example, if the aazimum number of inoperable MSSVs on any one steam generator is one, then w, should be a sumnarion of the capacity of the operable MSSVs at the highest operable MSSV operating pressure, exclaKag the highest capacity MSSV. If the maximum number of inoperable MSSVs per steam generator is thm- then w, should be a summation of the capacity of the operable MSSVs at the highest operable MS'perating prcssure, excluding the three highest capacity MSSVs.

h<< = Heateiivaporization for steam at the highest MSSV opening pressure including tolerance and accumulation, as appepriate in Btu/Ibm I 4 = Numb'f loops in plant The values ahalated from this algorithm are then adjusted lower for use in Technical Specification 3.7.1.1 to account for jument and channel uncertainties by 9%. This rcduccs thc maximum plant operating power level so that it is loser than the reactor protection system setpoint by an appropriate operating margin.

ATTACHMENT 3 TO AEP:NRC:1213A PROPOSED REVISED TECHNICAL SPECIFICATION PAGES

3/4 LIMITINGCONDlTIONS FOR OPERATION AND SURVEILLANCE REQUIREMENTS 3/4.7 PLANT SYSTEMS 3/4.7.1 TURBINE CYCLE SAFETY VALVES LIMITINGCONDITION FOR OPERATION 3.7.1.1 All main steam line code safety valves associated with each steam generator shall be OPERABLE.

APPLICABILITY: MODES 1, 2 and 3.

ACTION:

ao MODES 1 & 2: With 4 reactor coolant loops and associated steam generators in operation, and with one or more main steam line code safety valves inoperable, operation may proceed provided that within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, either the inoperable valve(s) are restored to OPERABLE status, or the Power Range Neutron Flux High Setpoint trip is reduced per Table 3.7-1; otherwise, be in HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and comply with action statement b.

b. MODE 3: With a minimum of 3 reactor coolant loops and associated steam generators in operation, and with one or more main steam line code safety valves associated with an operating loop inoperable, operation may proceed provided that within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, either the inoperable valve(s} atb restored to OPERABLE status, or the reactor trip breakers are opened; otherwise, be in HOT SHUTDOWN within the next 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

The provisions of Specification 3.0.4 are not applicable.

SURVEILLANCE RE UIREMENTS 4.7.1.1 Each main steam line code safety valve shall be demonstrated OPERABLE in accordance with Specification 4.0.5 and with liftsettings as shown in Table 4.7-1. The safety valve shall be reset to the nominal value +1% whenever found outside the +1% tolerance.

4.7.1.2 The provisions of Specification 4.0.4 are not applicable for entry into MODE 3.

COOK NUCLEAR PLANT-UNIT 1 Page 3/4 7-1 AMENDMENT420, 444, 4'

3/4 LIMITINGCONDITIONS FOR OPERATION AND SURVEILLANCE REQUIREMENTS 3/4.7 PLANT SYSTEMS TABLE 3.7-1 MAXIMUMALLOWABLEPOWER RANGE NEUTRON FLUX HIGH SETPOINT WITH INOPERABLE STEAM LINE SAFETY VALVES DURING 4 LOOP OPERATION Maximum Allowable Power Range Neutron Flux Maximum Number of Inoperable Safety Valves on High Setpoint An 0 eratin Steam Generator (Percent of RATED THERMAL POWER) 65.1 46.5 28.0 COOK NUCLEAR PLANT-UNIT 1 Page 3/4 7-2

3/4 .n BASES 3/4.7 PLANT SYSTE<MS 3/4.7.1 TURBINE CYCLE 3/4.7.1.1 SAFETY VALVES The OPERABILITY of the main steam line code safety valves ensures that the secondary system pressure will be limited to within 110% of its design pressure of 1085 psig during the most severe anticipated system operational transient. The maximum relieving capacity is associated with a turbine trip from 100% RATED THERMAL POWER coincident with an assumed loss of condenser heat sink (i.e., no steam bypass to the condenser).

The specified valve lift settings and relieving capacities are in accordance with the requirements of Section III of the ASME Boiler and Pressure Code, 1971 Edition. The safety valve is OPERABLE with a lift setting of J3%

about the nominal value. However, the safety valve shall be reset to the nominal value J1% whenever found outside the J1% tolerance. The total relieving capacity for all valves on all of the steam lines is 17,153,800 lbs/hr which is approximately 121 percent of the total secondary steam flow of 14,120,000 Ibs/hr at 100% RATED THERMAL POWER. A minimum of 2 OPERABLE safety valves per operable steam generator ensures that sufficient relieving capacity is available for the allowable THERMAL POWER restriction in Table 3.7-1.

STARTUP and/or POWER OPERATION is allowable with safety valves inoperable within the limitations of the ACTION requirements on the basis of the reduction in secondary system steam flow and THERMAL POWER required by the reduced reactor trip settings of the Power Range Neutron Flux channels. The reactor trip setpoint reductions are derived on the following bases:

ffso =i annfffi ~r (4w&

K where:

Hi 4= Safety Analysis power range high neutron flux setpoint in percent Q= Nominal NSSS power rating of the plant (including reactor coolant pump heat) in Mwt K= Conversion factor, 947.82 ~Btu/Sec Mwt Minimum total steam flow rate capability of the operable MSSVs on any one steam generator at the highest MSSV opening pressure including tolerance and accumulation, as appropriate, in lb/sec. For example, if the maximum number of inoperable MSSVs on any one steam generator is one, then w, should be a summation of the capacity of the operable MSSVs at the highest operable MSSV operating pressure, excluding the highest capacity MSSV. If the maximum number of inoperable MSSVs per steam generator is three, then w, should be a summation of the capacity of the operable MSSVs at the highest operable MSSV operating pressure, excluding the three highest capacity MSSVs.

hf Heat of vaporization for steam at the highest MSSV opening pressure including tolerance and accumulation, as appropriate in Btu/ibm 4 = Number of loops in plant The values calculated from this algorithm are then adjusted lower for use in Technical Specification 3.7.1.1 to account for instrument and channel uncertainties by 9%. This reduces the maximum plant operating power level so that it is lower than the reactor protection system setpoint by an appropriate operating margin.

COOK NUCLEAR PLANT-UNIT 1 Page B 3/4 7-1 AMENDMENT420

3/4 'IMITINGCONDITIONS FOR OPERATION AND SURVEILLANCEREQUIREMENTS 3/4.7 PLANT SYSTEMS 3/4.7.1 TURBINE CYCLE SAFETY VALVES LIMITINGCONDITION FOR OPERATION 3.7.1.1 All main steam line code safety valves associated with each steam generator shall be OPERABLE.

APPLICABILITY: MODES 1, 2 and 3.

ACTION:

MODES 1 & 2: With 4 reactor coolant loops and associated steam generators in operation, and with one or more main steam line code safety valves inoperable, operation may proceed provided that within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, either the inoperable valve(s) are restored to OPERABLE status, or the Power Range Neutron Flux High Setpoint trip is reduced per Table 3.7-1; otherwise, be in HOT STANDBY within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and comply with action statement b.

b. MODE 3: With a minimum of 3 reactor coolant loops and associated steam generators in operation, and with one or more main steam line code safety valves associated with an operating loop inoperable, operation may proceed provided that within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, either the inoperable valve(s) are restored to OPERABLE status, or the reactor trip breakers are opened; otherwise, be in HOT SHUTDOWN within the next 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

c. The provisions of Specification 3.0.4 are not applicable.

SURVEILLANCE RE UIREMENTS 4.7.1.1 Each main steam line code safety valve shall be demonstrated OPERABLE in accordance with Specification 4.0.5 and with liftsettings as shown in Table 4.7-1. The safety valve shall be reset to the nominal value +1% whenever found outside the +1% tolerance.

4.7.1,2 The provisions of Specification 4.0.4 are not applicable for entry into MODE 3.

COOK NUCLEAR PLANT-UNIT2 Page 3/4 7-1

3/4 LIMITINGCONDITIONS FOR OPERATION AND SURVEILLANCE REQUIREMENTS 3/4.7 PLANT SYSTEMS TABLE 3.7-1 MAXIMUMALLOWABLEPOWER RANGE NEUTRON FLUX HIGH SETPOINT WITH INOPERABLE STEAM LINE SAFETY VALVES DURING 4 LOOP OPERATION Maximum Allowable Power Range Maximum Number of Inoperable Safety Neutron Flux High Setpoint Valves on Any Operating Steam Generator (Percent of RATED THERMAL POWER) 61.6 43.9 26.2 COOK NUCLEAR PLANT-UNIT2 Page 3/4 7-2 AMENDMENT

3/4 'ASES 3/4.7 PLANT SYSTEMS 3/4.7.1 TURBINE CYCLE 3/4.7.1.1 SAFETY VALVES The OPERABILITY of the main steain line code safety valves ensures that the secondary system pressure will'be limited to within 110% of its design pressure of 1085 psig during the most severe anticipated system operational transient. The maximum relieving capacity is associated with a turbine trip from 100% RATED THERMAL POWER coincident with an assumed loss of condenser heat sink (i.e., no steam bypass to the condenser).

The specified valve lift settings and relieving capacities are in accordance with the requirements of Section III of the ASME Boiler and Pressure Code, 1971 Edition. The safety valve is OPERABLE with a lift setting of +3%

about the nominal value. However, the safety valve shall be reset to the nominal value J1% whenever found outside the +1% tolerance. The total relieving capacity of all safety valves on all of the steam lines is 17,153,800 lbs/hr which is at least 105 percent of the maximum secondary steam flow rate at 100% RATED THERMAL POWER. A minimum of 2 OPERABLE safety valves per steam generator ensures that sufficient relieving capacity is available for the allowable THERMAL POWER restriction in Table 3.7-1.

STARTUP and/or POWER OPERATION is allowable with safety valves inoperable within the limitations of the ACTION requirements on the basis of the reduction in secondary system steam flow and THERMAL POWER required by the reduced reactor trip settings of the Power Range Neutron Flux channels. The reactor trip setpoint reductions are derived on the following bases:

~r ffsto=taooft2t (4w&z )

K where:

Hi 4 = Safety Analysis power range high neutron flux setpoint in percent Q = Nominal NSSS power rating of the plant (including reactor coolant pump heat) in Mwt K = Conversion factor, 947.82 ~Bto/Sec Mwt w, = Minimum total steam flow rate capability of the operable MSSVs on any one steam generator at the highest MSSV opening pressure including tolerance and accumulation, as appropriate, in lb/sec. For example, if the maximum number of inoperable MSSVs on any one steam generator is one, then w, should be a summation of the capacity of the operable MSSVs at the highest operable MSSV operating pressure, excluding the highest capacity MSSV. Ifthe maximum number of inoperable MSSVs per steam generator is three, then w, should be a summation of the capacity of the operable MSSVs at the highest operable MSSV operating pressure, excluding the three highest capacity MSSVs.

h<< = Heat of vaporization for steam at the highest MSSV opening pressure including tolerance and accumulation, as appropriate in Btu/ibm 4 = Number of loops in plant The values calculated from this algorithm are then adjusted lower for use in Technical Specification 3.7.1.1 to account for instrument and channel uncertainties by 9%. This reduces the maximum plant operating power level so that it is lower than the reactor protection system setpoint by an appropriate operating margin.

COOK NUCLEAR PLANT-UNIT2 Page B 3/4 7-1 AMENDMENT82, 434

0 I

ATTACHMENT 4 TO AEP:NRC:1213A WESTINGHOUSE NSAL 94-001 "OPERATION AT REDUCED POWER LEVELS WITH INOPERABLE MSSV'S"

I Westinghouse Energy NUCLEAR SAF1TY ADVISORY LETTER Systems Business Unit

'HIS IS A NOTIHCATION OF A RECENTLY IDENTIFIED POTENTIAL SAFETY ISSUE PERTAINING TO BASIC BY WESTINGHOUSE. THIS INFORMATIONIS BEING PROVIDED TO YOU SO THAT A REVIEW OF THIS ISSUE CAN BE COMPONENTS'UPPLIED CONDUCED BY YOU TO DETERMINE IF ANY ACTION IS REQUIRED.

P. O. Box 355, Pittsburgh, PA 152304355

Subject:

Operation at Reduced Power Levels with Inoperable MSSVs Numbet: NSAL-944)01 Basic Component: Loss of Loadfi'urbinc Trip Analysis for Plant Licensing Basis Dates OII20$4 Plants: Sec Enclosed List Substantial Safety Hazard or Failure to Comply Pursuant to 10 CFR 21.21(a) Yes Ci No tl Transfer of Information Pursuant to 10 CFR 21.21(b) Ycs 0 Advisory Information Pursuant to 10 CFR 21.21(c)(2) Ycs 0

SUMMARY

Westinghouse has identified a potential safety issue regarding plant operation within Technical Specification Table 3.7-1. This issue does not represent a substantial safety hazard for your plant pursuant to 10 CFR 21. However, this issue does represent a condition which may impact your plant's licensing basis.

I Table 3.7-1 allows plants to operate with a reduced number of operable MSSVs at a reduced power level, as determined by the high neutron Qux trip setpoint. Thc FSAR loss of load/turbine trip (LOIJIT) analysis from full power bounds the case where ail MSSVs are operable. The FSAR (LOLfIT)event may not be bounding for the allowable operating configurations of Table 3.7-1 since the high neutron fiux trip setpojnt, which is identified in Table 3.7-1 for a corresponding number of inoperable MSSVs, may not be low enough to preclude a secondary side overpressurization condition. As a result, the basis for Table 3.7-1 may not be suQicient to preclude oveipressurization of the secondaty side of the steam generator.

'

Therefore, it is recommended that you review the enclosed information to deterinine thc applicability of this issue to your plant.

The enclosed infortnation contains a more detailed description of the issue and identifies solutions that you may wish to pursue to address this issue. These solutions include, but are not limited to, a reevaluation of the LOIJIT analysis and/or a change to

~

Technical Specification Table 3.7-1.

Additional information, if required, may be obtained from thc originator. Tclephonc 412-3746460.

Originator.

. W. Fasnacht H. A. Scpp, Manager, Strategic Licensing Issues Strategic Licensing Issues a%418.wpf: 1 b412094

Plants Affected D. C.Cook1 &2 J. M. Farley I & 2 Byron1 &2 Braidwood I & 2 V. C. Summer I Zion 1 &2 Shearon Harris I W. B. McGuire I & 2 Catawba I & 2 Beaver Valley I & 2 Turkey Point 3 & 4 Vogtle I & 2 Indian Point 2 & 3 Seabrook I Millstone 3 Diablo Canyon I &2 Wolf Creek Callaway I Comanche Peak I & 2 South Texas I & 2 Sequoyah I & 2 North Anna I & 2 Watts Bar I & 2 Size,well B Kori1,2,3 &4 Yonggwang I & 2 Salem I & 2

@%418.wpf:1b411994 II

0 4

Issue Descri tion Westinghouse has identified a deficiency in the basis for Technical Specification 3.7.1.1. This Technical Specification allows the plant to operate at a reduced power level with a reduced number of operable Main Steam Safety Valves (MSSVs). The deficiency is in the assumption that the maximum allowable initial power level is a linear function of the available MSSV relief capacity. The linear function is identified in the Bases Section for Technical Specification 3/4.7.1.1 and is provided as follows:

Sp = (X) aO(V) x (i(e)

X SP = Reduced reactor trip setpoint in % of RATED THERMALPOWER V = Maximum number of inoperable safety valves per steam line X = Total relieving capacity of all safety valves per steam line in ibm/hour Maximum relieving capacity of any one safety valve in Ibm/hour (109) = Power range neutron flux-high trip setpoint for all loops in operation Under cerfain conditions and with typical safety analysis assumptions, a Loss of Load/Drrbine Trip transient from part-power conditions may result in overpressurization of the main steam system when operWng in accordance with this Technical Specification. 'Ihe following discussion describes the issue in more detail and provides recommended alternatives for addressing the issue.

Technical Evaluation

'Ihe Loss of Load/Turbine Trip (LOLGT) event is analyzed in the FSAR to show that core pro~on margins are maintained (DNBR), the RCS will not overpressurize, and the main steam system will not oveipressurize. The analysis assumes an immediate loss of steam relieving capability through the turbine and coincident loss of all main feedwater. No credit is taken for the direct reactor trip on turbine trip, since this trip would not be actuated for the case of a loss of steam load. Rather, the transient is terminated by a reactor trip on high pressurizer pressure, overtemperature AT, or low steam generator water level. Secondary side ov'erpressure protection is provided by actuation of the Main Steam Safety Valves (MSSVs), which are designed to relieve at least full power nominal steam flow.

'Ilie analysis verifies that the MSSV capacity is sufficient to prevent secondary side pressure fimm .

exceeding 110 percent of the design pressure.

0%418.vq>f:tb411994

The FSAR only analyzes the LOIJIT transient Gom the M power initial condition, with cases examining the effects of assuming primary side pressure control and different reactivity feedback conditions. With fully operational MSSVs, it can be demonstrated that overpressure protection is provided for all initial power levels. However, for most plants, Technical Specification 3.7.1.1 allows operation with a reduced number of operable MSSVs at a reduced power level as determined by resetting the power range high neutron fiux setpoint. This Technical Specification is not based on a detailed analysis, but rather on the assumption that the maximum allowable initial power level is a linear function of the available MSSV relief capacity. Recently, it has been determined that this assumption is not valid.

'Ihe problem is that if main feedwater is lost, a reactor trip is necessary to prevent secondary side overpressurization for all postulated core conditions. At high initial power levels a reactor trip is actuated early in the transient as. a result of either high pressurizer pressure or overtemperature hT.

The reactor trip terminates the transient and the MSSVs maintain steam pressure below 110% of the design value.

At lower initial power levels a reactor trip may not be actuated early in the transient. An overtempeiature hT trip isn't generated since the core thermal margins are increased at lower power levels. A high pressurizer pressure trip isn't generated if the primary pressure control systems function normally. This results in a longer time during which primary heat is transferred to the secondary side.

'Ihe reactor eventually, trips on low steam generator water level, but this may not occur before steam pressure exceeds 110% of the design value ifone or more MSSVs are inoperable in accordance with the Technical Specification.

Due to the wide variety of plant design features that are important to the LOIJIT analysis, it is difficult to perform a generic evaluation to show that the issue does not apply to certain plants. The following key parameters have a significant effect on the secondary side pressure transient MSSV relief capacity Moderator Temperature Coefficient (MTC)

Margin between the MSSV set pressures (including tolerance) and the overpressure limit Low-low steam generator water level reactor trip setpoint Safet Si nificance The Technical Specifications for most plants allow operation at a reduced power level with inoperable MSSVs. From a licensing basis perspective, this condition may result in secondary side overpressurization in the event of a LOIJIT transient. The licensing basis for anticipated operational occurrences (ANS Condition II events) typically requires that the secondary side prcssure remain below 110% of the design value.

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Westinghouse has determined that this issue does not represent a substantial safety hazard. There are several mitigating factors which provide assurance that there is no loss of safety function to the exteat that there is a major reduction in the degree of protection provided to the public health and safety.

These include, but are not limited to, the following:

1. Adequate overpressure protection is provided at all power levels ifall of the MSSVs are operable.

2. Ifa reactor trip does not occur but main feedwater fiow is maintained, operation in accordance with the Technical Specification Table 3.7-1 will not result in an overpressure condition.

3. In any LOIJIT transient, the atmospheric steam dump valves and/or condenser steam dump valves actuate to relieve energy irom the steam generators prior to the opening of the MSSVs, and continue to relieve steam if the MSSVs do open. Since it is not a safety-grade function, steam dump is not assumed to operate in the safety analysis; however, in reality it is the first line of defense in protecting the secondary system against overpressurizatioa. It is very improbable that all these compoaents would be inoperable coincident with inoperable MSSVs.

4. Even near the beginning of core life with a positive or zero MTC, the primary volant heatup resulting from the transient would tend to drive the hGC negative, which would .

reduce the core power aad heat input to the coolaat. This would result in'a lower required MSSV capacity to prevent secondary ovegressurization. The safety analysis does not credit the reduction of MTC during the transient.

NRC Awareness I Re ortabilit Westinghouse has not notified the NRC of this issue, based upon the determination that it does aot represent a substantial safety hazard pursuant to 10 CFR 21. However, Westinghouse will send a copy of this letter to the NRC since this issue impacts information contained in NUREG-1431, "Standard Technical Specifications, Westinghouse Plants".

Recommendations To address this issue, the following actions may be considered:

(1) Modify Techaical Specificatioa 3.7.1.1 (or equivalent) and the associated basis such that the maximum power level allowed for operation with inoperable MSSVs is below the heat removing capability of the operable MSSVs. A conservative way to do this is to set the power range high aeutmn fiux setpoint to this power level, thus ensuring that the actual power level cannot exceed

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~ ~

this value. To calculate this setpoint, the governing equation is the relationship q = m hh, where q is the heat input fmm the primary side, m is the steam flow rate and hh is the heat of vaporization at the steam relief pressure (assuming no subcooled fecdwater). Thus, an algorithm for usc in defining the revised Technical Specification table setpoint values would be:

(wPN)

Hi g = (100/Q) ~

K where:

'i g = Safety Analysis power range high neutron flux setpoint, percent Q = Nominal NSSS power rating of the plant (including reactor coolant pump heat), Mwt K = Conversion factor, 947.82 Mwt ws Minimum total steam low rate capability of the operable MSSVs on any one steam generator at the highest MSSV opening pressure including tolerance and accumulation, as appropriate, in ib/sec. For example, ifthe maximum number of inoperable MSSVs on any one steam generator is one, then w, should be a summation of the capacity of the operable MSSVs at the highest operable MSSV operating prcssure, excluding the highest capacity MSSV. Ifthe maximum number of inoperable MSSVs per stcam generator is three then w, should be a summation of the capacity of thc operable MSSVs at the highest operable MSSV operating prcssure, excluding the three highest capacity MSSVs.

h+ = heat of vaporization for stcam at the highest MSSV opening pressure including tolerance and accumulation, as appropriate, Btu/1bm N = Number ofloopsin plant The values calculated from this algorithm must then be adjusted lower for usc in Technical Specification 3.7.1.1 to account for instrument and channel uncertainties (typically 9% power).

The maximum plant operating power level would then be lower than the reactor protection system setpoint by an appropriate operating margin.

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k k

~ ~

y 0

C

~ c.

It should be noted that the usc of this equatioa will resolve the issue ideatified in this letter by eaabling you to re~culate your Technical Specification 3.7.1.1 setpoints without further modifications to the structure of the Tcchnical Specification. The re-calculated setpoints are likely to be lower than those currently allowed by the Techaical Specification. However, you should be aware of at least two conscrvatisms with the equation You may wish to review these conservatisms to evaluate the use of the equation relative to your plant specific operating objectives. It is possible to relax some of these conservatisms for use in the Technical Specificatioa However, relaxation of the conservatisms are likely to result in more significant changes to the structure of the Technical Spccificatioa First, the above equatioa (and the existing Techaical Specification 3.7.1.1) is conservative since it is based on the maximum number of inoperable MSSVs per loop. For example, a representative four loop plant, in accordance with the current Technical Specification, should if reduce'he neutron flux setpoint to 87% it has up to one inoperable MSSV on each loop.

This means that the plant should use this setpoint whether there are one, two, three or four inoperable MSSVs, as long as there is only one inoperable MSSV pcr loop. Thus, the existing Technical Specification and the above equation are conservative and bounding. However, any relaxation of this conservatism must be interpreted with care. The reason is that the steam generators must be protcctcd 6'om an ovcrpressurization condition during a loss of load transient. 'I%ere are several events that could lead to a loss of load, including the inadvertent closure of one or all MSIVs. The affected steam generator must have a sufficient number of operable MSSVs to protect it from an overpressurizatioa condition, ifthe MSIV (or MSIVs) was iaadvertently closed.

Another conservatism in the above equation (and the existing Technical Specification 3.7.1.1) is in wwhich is the minimum total steam Qow rate capability of the operable MSSVs on any one steam generator. This value is conservative since it assumes that ifone or more MSSVs are inoperable per loop, the inoperable MSSVs are the largest capacity MSSVs, regardless of whether the largest capacity MSSVs or the smaller capacity MSSVs are inoperable. The assumption has been made so that the above equation is consistent with the current structure of Technical Specification 3.7.1.1.

tbsp (2) As an alternative, plant-specific LOIJIT analyses could be performed to maximize the allowable power.level for a given number of inoperable MSSVs. Depending on key specific plant parameters, these analyses may be able to justify the coatinued validity of the current Technical Specificatioa (3) Consider modifying, as required, the Bases Section for Techaical Specification 3/4.7.1.1 so that.

it is consistent with the plant safety analysis. The safety analysis criterion for preventiag ovciprcssurization of the secondary side is that the prcssure does not exceed 110% of the design p essure for anticipated transients. However, in reviewing several plant techaical specifications, a%418.wpf: 11994

it was noted that the bases for some plants state that the safety valves insure that the secondary system pressure will be limited to within 10S or even 100%%uo of design prcssure. This is not consistent with the safety analysis basis and should be revised to indicate 110%.

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