ML18029A140

Proposed Tech Specs Replacing Functional Test Requirement for Reactor Protection Sys W/Requirement to Trip Channel Containing Failure within 1 H

ML18029A140
Person / Time
Site:	Browns Ferry
Issue date:	09/21/1984
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML18029A137	List: ML18029A136 ML18029A140
References
TVA-BFNP-TS-200, NUDOCS 8410020248
Download: ML18029A140 (15)

Text

ENCLOSURE 1 PROPOSED TECHNICAL SPECIFICATION REVISIONS BROWNS FERRY NUCLEAR PLANT UNITS 1, 2, AND 3 (TVA BFNP TS 200) 84i0020248 84092k PDR ADOCK 05000259 PDR .

PROPOSED UNIT 1 TECHNICAL SPECIFICATION REVISIONS SVltVEIILANCE kl+UIREMENTS 3.1 REACI'OR 1'ROTECTION SYSTEM 4m 1 REACTOR PROTECTION SYSTEM A licabilit A licabilit Applies to the instrumentation Applies to the surveillance and associated devices the instrumentation and asso a reactor scram. which'nitiate ciated devices which initiate reactor scram.

~ob ective ~ob ective To assure the operability of the To specify the type and frequency reactor protection system. of surveillance to be applied to the protect'ion instrumentation.

S e'cification S ecification

~ When there is fuel in the vessel, A. Instrumentation systems shall the setpoints,'inimum number of be functionally tested and trip systems, ~ and minimum number calibrated as indicated in of instrument channels that mu'st Tables'.1.A and 4.1.9 respec-

.be operable for each position of tively.

the reactor mode switch shall be as given in Table 3.1.A".

2 When it is determined that one channel is failed in the unsafe condition, that channel con-taininE the unsafe failure will be tripped within one hour.

B. Two'PS power monitoring channels for each inscrvice'PS HP sets or alternate souri c shall hc: <ipurabl e.

l. With one RPS cle'ctric

~,- pnwer monitoring channel for inservice RPS MG set or alternate power supply inoperable, restore the inoperable channel to opcral>le status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or remove the associated RPS MG set or alternate power supply from service.

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PROPOSED UNIT 2 TECHNICAL SPECIFICATION REVISIONS LIMITING CONDITIONS FOR OPERATION. SURVEILLANCE REQUIREMENTS 3~ 1 REACTOR PROTECTION SYSTEM 4e 1 REACTOR PROTECTION SYST A licabilit e Applies to the surveillance of Applies to the instrumentation the instrumentation and and 'associated devices which associated devices which initiate a reactor scram. initiate reactor scram.

~cb ective To specify the type and

~ob 'ective frequency of suxveillance to be applied to the protection To assure the operability of instrumentation.

the reactor protection system.

S cification

'I ecification Instrumentation systems S shall be functionally v tested and calibrated's

~ A. 1 Mhen thex'e is fuel in the vessel, indicated in Tables 4.1.A the setpoints~ minimum number of and 4.1.B respectively.

trip SyStems, and minimum number ~

of instrument channels that must, B. Daily during reactor power operation be operable for each position of, at greater than or equal to 25/

the reactor mode switch shall be thermal power, the ratio of fraction as given in Table 3.1.A.

of Rated Power (FRP) to Core 1 Maximum Fraction of Limiting Power Density {CMFLPD) shall be checked and the scram and APRH Rod Block 2 Mhen it is determined that one settings given by equations in channel is failed in the unsafe specifications 2.1.A.1 and 2.1.B condition, that channel con- shall be calculated.

taining the unsafe failut e will be tripped within one hour.

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PROPOSED UNIT 3 TECHNICAL SPECIFICATION "REVISIONS

• I cl

LIMITING CONDITIONS POR OPERATION. SURVEILLANCE REQUIREMENTS 3~ 1 REACTOR PROTECTION SYSTEM 1 REACTOR PROTECTION 8 STEM A licabilit cab't Applies to the surveillance of Applies to the instrumentation the instrumentation and and associated devices which associated devices which initiate a reactor scram. initiate reactor scram.

Ob ective To specify the type and

~Oh QctivQ frequency of surveillance to be applied to the protection To assure the operability of instrumentation.

the reactor protection system.

S cification ecification A Instrumentation systems S

shall be functionally tested and calibrated as A. 1 When there is fuel in the vessel,, indicated in Tables 0.1.A the setpoints, minimum number of and 0.1.B respectively.

trip systems, and minimum number ~

B. Daily during reactor power operation of instrument channels that must be operable for each position of, at greater 'than or equal to 25%

the reactor mode switch shall be thermal power, the ratio of fraction as given in Table 3.1.A. of Rated Power (FRP) to Core Maximum Fraction of Limiting Power Density (CMFLPD) shall be checked and the scram and APRM Rod'lock When it is determined that one settings given by equations in channel is failed in the unsafe specifications 2.1.A.l and 2.1.B condition, that channel con- shall be calculated.

taining the unsafe failure will be tripped within one hour.

3l LJn)k 3

ENCLOSURE 2 DESCRIPTION AND JUSTIFICATION (TVA BFNP TS 2'00)

Descri tion of Cha e:

Technical specification section 4 .1.C contains a requirement that upon the failure of a reactor protection system ( RPS) channel in the unsafe condi-tion all RPS channels monitoring the same variable must be functionally tested. This testing must be performed immediately before the trip system containing the failure is tripped . The trip system may be in the untripped position for up to eight hours to perform the functional test.

The RPS is made up of two independent trip systems. There are usually four channels provided to monitor each cr itical parameter, with two channels in each trip. system. The outputs of the channels in a trip system are com-b1ned in logic such thateither channel trip will trip that trip system.

simultaneous tripping of both trip systems will produce a reactor 'he scram.

An unsafe failure means that the failure did not result in tripping the channel and thus the trip system. Testing the other channels ensures that there are no other unsafe failures. However, in order to do this testing, the trip system containing the failure can be left as is for up to eight hours in order to test the other trip system.

The proposed revision is to delete the functional test requirement and replace it with a requirement to trip the channel containing the failure within one hour. The proposed amendment reflects that of the Standard Technical Specifications.

Justification:

The FSAR section 7 .2 .2.7b states: "Any one intent'ional bypass, ma1ntenance

~

operation, calibration operation, or test to verify operational availability shall not impair the ability of the reactor protection system to respond correctly." The current technical specifications allow leaving the trip system containing the unsafe failure in the untr1pped condition for up to eight hours in order to functionally test the other trip system. This could

'ossibly lead to a situation which could impair the ability of the RPS .to respond correctly. By tr ipping the channel within one hour, the probability of impair ing the response of the RPS is decreased, and thus, the margin of

', safety is increased. The proposed revision also makes this section like

'hat in the Standard Technical Specif1cations.

~ ~ c l ENCLOSURE 3 PROPOSED NO SXGNXFICANT HAZARDS CONSIDERATXON DETERMINATION (TVA BFNP TS 200)

Descri tion of Cha e:

Technical specification section 4.1.C conta1ns a requirement that upon the failure of a reactor protection system (RPS) channel in the unsafe condition all RPS channels monitoring the same variable must be functionally tested.

This testing must be performed immediately before the trip system containing the failure is tripped . The trip system may be in the untr ipped position for up to eight hours to perform the functional test.

The RPS is made up of two independent trip systems. There are usually four channels provided to monitor each cr itical parameter, with two channels in each trip system. The outputs of the channels in a trip system are combined in logic such that either channel trip will trip that trip system. The simultaneous ff tripping of both trip systems will produce a reactor scram.

0 An unsafe failure means that the failure did not result in tr 1pping the channel and thus the trip system. Testing the other channels ensures that there are no other unsafe failures. However, in order to do this testing, the trip system containing the failure can be left as is for up to eight hours in order to test the other trip system.

The proposed revision is to delete the Anctional test requirement and replace it with a requirement to tr1p the channel containing the failure within one hour. The proposeg amendment reflects that of the Standard Technical Specifications.

Bas1s for Pro osed No S nificant Hazards Determination:

NRC has provided guidance concerning the application of the standards by'"

providing examples of actions that are not likely to involve s1gnificant hazards considerations (48FR14870). One example of act1ons not likely to involve a significant hazards consideration is a change which either may result in some increase to the probability or consequences of a previously-analyzed accident or may reduce in some way a safety .margin, but where the results of the change are clearly within all acceptable criteria with respect to the system or component specified in the Standard Rev1ew Plan.

The proposed amendment 1s encompassed by this example in that the revision

-reflects the requirements establ1shed in the Standard Techn'ical Specif1ca-tions. Also, by tripping the channel in one hour as opposed to -eight hours, the probability of impairing the ability of the RPS to respond correctly is decreased. This results in an increase in the margin of safety.

Therefore, TVA proposes to determine that the proposed amendment does not involve a s1gnificant hazards consideration.

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