ML20066D284

Proposed Tech Spec Revisions,Allowing Operation Up to 30 Days W/One Temp Switch in Main Steam Tunnel Inoperable

ML20066D284
Person / Time
Site:	Browns Ferry
Issue date:	11/03/1982
From:	TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20066D268	List: ML20066D266 ML20066D284
References
NUDOCS 8211110265
Download: ML20066D284 (5)

Text

!

e i

2 ENCLOSURE 1 PROPOSED TECHNICAL SPECIFICATION REVISIONS (TVA BFNP TS 144 SUPfl. DENT 1) 3 i

s 1

l l

4 i.

I a

i e

i t-8211110265 821103 PDR ADOCK 05000259 PDR .-

UNIT 1

6. Channel shared by RPS and Primary Containment & Reactor vessel Isolation control System. .A channel failure may be a channel failure in each system.

7. A train is considered a trip system.

6. Two out of three SGTS trains required.

than one will require action A and F. A failure of more

• 9.

There sources. is only one trip system with auto transfer to two power

10. kafer to Table 3.7.A and its notes for a listing of Isolation Valve Groupe and their initiating signals.

II* A channel <nay be placed in an inoperable status for up to four hours for required surveillance without placing the trip system in the tripped condition is monitoringprovided at least one OPERABLE channel in the same trip system that parameter.

12. Power operations permitted for up to 30 days with 15 of the 16 temperature switches operable.

• i, 61

__.m -._ . _ _ .

d UNIT 2

6. Channel shared by RPS and Primary Containment & Reactor Vessel Isolation Control System. A channel failure may be a channel failure in each system.

7. A train is considered a trip system.

8. Two out of three SGTS trains required. A failure of more

• than one will require action A and F.

9.

There sources. is only one trip system with auto transfer to two power

10. Refer to Table 3.7.A and its notes for a listing of Isolation Valve Groups and their initiating signals.

gg, A channel stay be placed in an inoperable status for up to four hours for required surveillance without placing the trip system in the tripped condition provided at least one OPERABLF. channel in the same trip system is monitoring'that parameter.

12. Power operations permitted for up to 30 days with 15 of the 16 temperature switches operable. '

l l

61 1

5

,,---s -,- e , , - ---

0 UNIT 3

3. There are four channels per steam line of which two must be operable.

4 Only required in Run Mode (interlocked with Mode switch) .

5. Not required in Run Mode (bypassed by mode switch).

6. Channel shared by RPS and Primary Containment G Reactor vessel channelIsolation failure inControl System. A channel failure may be ,a each system.

7. A train is considered a trip system.

8. Two out of three SGTS trains required. A failure of more than one will require action A and F.

9.

There sources. is only one trip system with auto transfer to two power

10. Refer to Table 3.7.A and its notes for a listing of Isolation Valve Groups e

and their initiating signals.

11. A channel may be placed in an inoperable status for up to four hours for

,i required surveillance without placing the trip system in the tripped j condition provided at least one OPERABLE channel in the same. trip system

• is monitoring that parameter. -

l

' 12. Power operations permitted for up to 30 days with 15 of the 16 temperature switches operable, ,

i i

t 63 1

l

.+ .

ENCLOSURE 2 DESCRIPTION AND JUSTIFICATION (TVA BFNP TS 144 SUPPLEMENT 1)

This proposed revision requests adding a note to Table 3 2.A to permit power operations to continue for up to 30 days with 15 of the 16 temperature switches operable. Currently, a failed switch will I produca a half-isolation signal on the MSIVs. In this condition, any isolation trip signal on the other trip bus would cause a full MSIV isolation and a resultant reactur trip. The failed switch could not J

be replaced during power operations since .it is located in a hazardous i

area and in a high radiation zone. - By allowing the switch to be bypassed and operation to continue- for up to 30 days, a brief plant shutdown could be planned at a time that has minimal impact on operational needs and load demand. It would also allow time to plan a more economical use of the shutdown time.

In the steam tunnel, nain steam line temperature is monitored by nonindicating temperature switches in sets of four placed along each main steam line for a total of 16 switches. The trip logic for this function is made up of two trip systems, each of which is required to have two operable trip channels. Each channel is comprised or four temperature switches, at present, all of which must be operable for the channel to be operable. This trip logic provides a one-out-of-two-taken-twice logic for actuation of a group 1 isolation.

All temperature switches are located within the steam tunnel with space communication between then. If one switch is inoperable,-there are three other switches that monitor the same steam line and 12 l switches in close proximity. If a steam leak or break occurs, it l would be detected by the 15 renaining switches. These 15 switches l would still provide three fully functional channels and one operable channel with three switches.

The design basis of the main steam line temperature trip is to protect against a main steam line hecak. Within the group 1 isolation logic, two other parameters also protect against a steam line creak; (1) main steam line high flow, and (2) reactor low water Invel.

With one temperature switch inoperable adequate redundancy still remains with 15 switches operable and the main steam lice high flow and the reactor low water level functions operable to assure prompt isolation when needed.

Based on the above, operation with 15 of 16 temperature switches operable for a period of up to 30 days does not present an l unacceptable risk to plant safety. l