ML20203D106

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Proposed Tech Specs Revising Surveillance Testing Requirements for Emergency Feedwater Sys
ML20203D106
Person / Time
Site: Arkansas Nuclear Entergy icon.png
Issue date: 02/18/1998
From:
ENTERGY OPERATIONS, INC.
To:
Shared Package
ML20203D104 List:
References
NUDOCS 9802250352
Download: ML20203D106 (7)
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Text

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3/4.7 PLANT SYSTEMS BASES 3/4.7.1 TURBINE CYCLE 3/4.7.1.1 SAFETY CYCLES The OPERABILITY of the main steam line code safety valves ensures that the secondary system pressure will be limitcd to within 110% of its design pressure of 1100 psia 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).

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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 "as-found" requirements are conservative with respfet to Section XI of the ASME Boiler and Pressure Vessel Code, 1986 Edit!)n, and Addenda through 1987. The total relieving capacity for all MSSVs is 14,804,000 lb/hr. The ANO-2 full

\ power (100%) steam LAow plus 2% for conservatism is 12,950,000 lb/hr.

j Therefore, the total relieving capacity of the MSSVs is 114.32% of the 102% power steam flow through each main steam header. A minimum of 2 OPERABLE safety valves per steam generator ensures that sufficient relieving capacity is available for removing decay heat.

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 Level-High channels. The reactor trip setpoint reductions are derived on the following bases:

L-SP = (X) - (Y) x (114.32%)

X where SP = reduced reactor trip setpoint in percent of RATED THERMAL POWER

, 114 . 32 % = Total maximum safety valve relieving capacity of 102% power steam flow X = Total relieving capacity of all safety valves per steam line in 1bs/ hour Y = Total Maximue relieving capacity of the inoperable safety valve (s) in lbs/ hour. In each case, the valves with the greatest relieving capacity were assumed inoperable.

E ARKANSAS - UNIT 2 B 3/4 7-1 Amendment No. MO,MO,

-PLANT SYSTEMS BASES 3/4.7.1.2 EMERGENCY FEEDWATER SYSTEM i -The OPERABILITY of the emergency feedwater (EFW) system ensures that the Reactor Coolant System can be cooled down to Shutoown Cooling ISDC) entry conditions from normal operating conditions in the event of a total loss of off-site power.

The EFW system is designed to supply sufficient water to the steam generator (s) to remove decay heat with steam generator pressure at the setpoint of the MSSVs. Subsequently, the EFW system supplies sufficient water to cool the unit to SDC entry conditions, and steam is released through the ADVs.

SR 4.7.1.2.b.1 verifies that each EFW pump's developed head at the flow test point is greater than or equal to thir required developed head. This test ensures that EFW pump performance has not degraded during the cycle. Flow and differential head are normal' tests of pune performance required by Section XI of the ASME Code. Because it is undesirable to introduce cold EFW into the steam generators while they are operating, this testing is performed on recirculation flow. This test confirms one point that is indicative of pump overall performance. Such inservice tests confirm component OPERABILITY, trend performance, and detect incipient 'f ailures by indicating abnormal performance.

Performance of inservice testing, discussea in the ASME Code,Section XI, satisfies this requirement. The SR for the turbine driven EFW pump is allowed to be deferred for up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after exceeding 700 psia in the steam generators. This allowance will ensure the test is completed within a reasonable period of time after establishing sufficient steam pressure to perform the test.

SR 4.7.1.2.c ensures that EFW can be delivered to the appropriate steam generator, in the event of any accident or transient that generates an EFAS signal. This is assured by demonstrating that each automatic valve in the flow path actuates to its correct position on an actual or simulated actuation signal. The 18 month frequency i. based on the need to perform the SRs under the conditions that apply during a unit nutage and the potential for an unplanned transient if the SRs were performed with the reactor at power.

> SR 4.7.1.2.d ensures that the EFW System 16 properly aligned by verifying the flow path from the condensate storage tank (CST) to each steam generator prior to entering MODE 2 operation, after more than 30 days below MODE 3.

OPERABILITY of the EFW flow paths must be verified before sufficient core heat is generated that would require the operation of the EFW System during a subsequent shutdown. The Frequency is reasonable, based on engineering judgment, and other administrative controls to ensure that flow paths remain OPERABLE. To further ensure EFW System alignment, the OPERABILITY of the flow paths is verified following extended outages to determine that no udsalignment of valves has occurred. This SR ensures that the flow path from the CST to the steam generators is properly aligned.

3/4.7.1.3 CONDEMSATE STORAGE TANK The OPERABILITY of the condensate storage tank with the minimum water volume ensures that sufficient water is available to maintain the RCS at HOT STANDBY conditions for one hour with steam discharge to atmosphere with concurrent with total loss of off-site power. The contained water volume limit includes an allowance for water not usable because of tank discharge line location or other physical characteristics.

ARKANSAS - UNIT 2 B 3/4 7-2 Amendment No. M O,

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BASES 3/4.7.1 TURBINE CYCLE 3/4.7.1.1 SAFETY CYCLES The OPERABILITY of the main steam lir code safety valves ensures that the secondary system pressure will be limited to wichin 110% of its design pressure of 1100 psia during the most severe anticipated system-operational transient. The umximum 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 accced. ace with the requirements of Section III of the ASME Boiler and Pressure Code, 1971 Edition. The "as-found" requirements are conservative with respect to Section XI of the ASME Boiler and Pressure Vessel Code, 1986 Edition, and Addenda through 1987. The total relieving capacity for all MSSVs is 14,804,000 lb/hr. The ANO-2 full power (100%) steam flow plus 2% for conservatism is 12,950,000 lb/hr.

Therefore, the total relieving capacity of the MSSVs is 114.32% of the 102% power steam flow through each main steam header. A minimum of 2 OPERABLE safety valves per steam generator ensures that sufficient e relievang capacity is available for removing decay heat.

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 Level-High channels. The reactor trip setpoint reductions are derived on the following bases:

SP = (X) -

(Y) x (114.32%)

X where:

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SP = reduced reactor trip setpoint in percent of RATED THERMAL POWER 1112221 - Total maximum safety valve relievina capacity of 102% oower 3_ team flow g = "otal relievina capacity of all safety valves per steam

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= Total Maximum relievina capacity of the inocerable safety valve (s) in lb1/ hour. In each ease, the valves with the createst relleyina capacity were assumed inoperable t ARKANSAS - UNIT 2 B 3/4 7-1 Amendment No. 444,MO,

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9:::t::t ::lievin; ::p :ity u::: :::n- d in:;:::bler 3/4.7.1.2 EMERGENQY FEEDWATER SYSTEM The OPERABTLITY of the emergency feedwater ,[Efw1_ system ensures that the Reactor Coolant System can be cooled down to Shutdown Cooljna (SDC) entry 29 Adit 190fic : th n 350'i from normal operating conditions in the event of a total loss of off-site power.

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h -- :;;;;y f:: duct:: ;- i: ::;251: f delivering : t:tel f:: duct : fl eu c f " 5 ,;- : t : peeeew:: Of 1100 p;ig t; th; :nt :n;; cf th: :t: = ;;;:::t;;;. Thi; ::p:efty i: : ff4:1:nt t: :n:::: th:t :d: ;;:t; f:: duct:: f4ew-4.-eve 44eM: t: :: :n d:::y h::t nd nd :: th: ";;:tze Gee 4:nt "y:t:= t: ;;;;tur: t:-10:: then 350'T uh;; th: Chutd:L- :::14*g ey;t:= :y b: ple :d int p:::ti+nr The EW system is desigggd to_ supply _suf ficient water to the st3g generator (s) to lemove dgcay heat with steam aenerator pressure at the setooL Rt of the_MSSVs. Sukugggnily, the EN system gpp]ies suf ficient water to cogA the unit _to_RDC entry conditions, and steam is releaged thiqugh the ADVs.

SR 4.7.1.21b.1 veg111es_ that esch_EN Dymp's dgydpped head at the flow test point is creater than or eaual to this re_qqired c eveloped head. This test

. ggyres that EN_gggg, performance has not dggggggg_durina the evele. Flow and d_ifferential head are normal tegs of oumo performance require,d by Section XI of the ASME Code. Be,gause it 1.s undesirable to introdure cold EN into the steam generato_rs while they are operatina, this testina is performed on recarculatLon flow. This test confirms-one point that is indicative of py,gg overala RSIformance. Such inservice tests confirnLqj;gpgg,(_QEElgILITY, t rertd ggyformance, and_. detect ineioient f 311greg_by_indlSMing,Abnorma1 oerforganggi gggformance of inservice testing, discussed in the ASME Code,Section XI.

- satisfies this reauirement. The SR for the turbine driven EFW nuen is allowed

-Le be deferred for un to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> af ter exceedina 700 meia in the steam a=narators. This allowance will ensure the test is completed within a reasonable meriod of time after establishina sufficient steam cressure to pe Tle.Em the_ tem _t.t SR 4.7.1.2.o ensures that E M can be delivered to the anorocriate steam

- =rator, in +h= event of any accident or transient that eenerates an EFA5 signal. This is assured by demonstratina that each automatic valve in the flow math actuates to its correct nosition on an actual or simatlated actuation sienal. The 10 month freauency is based on the need to perform the SRs under the a-H tions

  • hat anolv durina a unit outmaa and the notential for an unnlanned transient if the SRs were nerformed with the reactor at power,

- SR 4.7.1.2.d ensures that the EFW System is crocerly alioned by verifyina the flow path from the condensate _a_toggge tank (CST) to each steam a ggI31qt orior to enterina MODE 2 operathon, after more than 30 days below MODE 3.

OPERABILITY of the EN flow o_aths must be verified befgre suf ficient core heat is aenerated that would require the operation o ' the EN System durina a pubneauent shutdown. The Frecuency is rqaggngbhe, based on enaineerina ARKANCAS - UNIT 2 B 3/4 7-2 Amendment No, MO, l

AgdQmenn .and othter . administrative controh,ent >re that fimglhfMAD QHJB&lE. To_furthtL intRte-_EIV_Sys3em aliSDEigt. the OPEPABILITY of the flow

, Rath a is yerified iol[gipultadgd outaaes to de1HEig#Jkat_R9_Rhallanmini pf__ valves has occurled. This_3R_enRMLtp_that the_ flow.f ath_from the CST to the attam_ genera _ tore la _pLgreriv__ e11gnedi 3 / 4 . *1.1. 3 CONDENSATE STORAGE TANK The OPERABILITY of the condensate storage tank with the minimum water vo',ume ensures tha; suf ficient water is available to maintain the RC'1 at HOT STANDBY co. editions for one hour with steam discharge to atmosphere with concurrent with total loss of off-site power. The contained water volume limit includes, an allowance for water not usable because of tank

discharge line location or other physical characteristics.

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1 ARKANSAS - UNIT 2 B 3/4 ~7-2 Amendmeia No. MO,

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