ML20198F221

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Proposed Tech Specs,Providing Suppl Info Re Amends to Licenses to Convert STP TS to Improved STS Format
ML20198F221
Person / Time
Site: South Texas  STP Nuclear Operating Company icon.png
Issue date: 08/05/1997
From:
HOUSTON LIGHTING & POWER CO.
To:
Shared Package
ML20198F219 List:
References
NUDOCS 9708110226
Download: ML20198F221 (5)
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CORRECTED DISCUSSION OF CilANGES (DOCS) PAGES FOR IMPROVED TECilNICAL SPECIFICATIONS SECTION 3.6 NEPLACEMENT l' AGES i

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l STP ITS Cony:rsion Discussion of Changes Section 3.6 CONTAINMENT SYSTEMS IECHNICAL CHANGES LESS RESTRICTIVE this Surveillance from 5 to 10 years is reasonable based on the passive nature of the spray header and operating history.

This change in ITS 3.6.6 is less restrictive and consistent with NUREG-1431.

L.13 The proposed ITS Action C is added to allows two trains of containment spray to be inoperable for a period up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> i' days. Three trains of containment spray are currently required by B CTS 3.6.2.1. and if more than one spray system is inoperable, LCO 3.0.3 would be entered. The proposed ITS Action is not intended to be used to voluntarily remove two trains from service, it is intended to allow time to restore one train to OPERABLE status, when one train is removed from service and another train becomes inoperable for unplanned reasons. In the ITS, containment spray and centainment-cedlag RCFC are combined in LCO 3.6.6. By combining the two systems into one specification, NUREG.

1431 relates the dependance of the systems in their function to remove energy from the containment atmosphere. With the required trains of contah. ment-cooling BCLC_and one train of containment spray operable, a significant portion of the containment energy removal capability remains available.

The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> i' days Completion Time is a reasonable time for repairs and a low probability of a DBA occurring during this period of time and is supported by the Anolication of t(m Probabilistic Safety Assessment to the South Texas Project 115. Thinhange b !cz restric4iveed-e<mestent.vith the ph!!csaphy of NUREG 1131.

L.14 The proposed ITS Action D is added to allow two trains of containment coc!!ng RCFC to be inoperable for a period up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> i' days. Three trains of centa!nment cooling RCfC_are currently required by M CTS 3.6.2.1. and if more than one coc!!ng system RCFC train __is inoperable, LCO 3.0.3 would be entered. This Action is not intended to be used to voluntarily remove two trains from service, it is intended to allow time to restore one train to OPERABLE status, when one train is removed from service and another train becomes inoperable for unplanned reasons, in the ITS, containment spray and containment coaHog RCFC are combined in LCO

- South Texas Units 1 & 2 Page L - 6 Rev. O, 07/18/97

STP ITS Conv:rsi:n Discussion of Changes Section 3.6 CONTAINMENT SYSTEMS TECHNICAL CHANGES - LESS RESTRICTIVE 3.6.6. By combining the two systems into one specification, NUREG 1431 relates the dependance of the systems in their function to remove energy from the containment atmosphere.

With the required trains of containment spray and one train of containment 4ooling fLCLC operable, a significant portion of the containment energy removal capability remains available. The 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> Nays Completion Time is a reasonable time for repairs and a low probability of a DBA l

occurring during this period of time and is sunnarted bvh Apolication of the ProbabHistic Safety Assessment to the South Texas Proiect ITS.--Thiwhange+rleswestek4ivcwml l

eensistent-with-the1>hilosophy-of-NUREC 1434, L.15 The existing Action for one inoperable recombiner becomes Action A cf the ITS. A Note is added to CTS 3.6.4.2 Action to provide an exception to Specification 3.0.4 that would allow Mode change to be made with one inoperable recombiner. The Note is appropriate since the other hydrogen recombiner remains available to perform the post accident function. This change in ITS 3.6.7 is consistent with NUREG-1431.

L.16 A new Action has been added to CTS 3.6.4.2. This Action describes the requirements for two hydrogen recombiners being inoperable. This proposed change allows up to 7 days to restore one hydrogen recombiner to OPERABLE status. This is based on conservative assumptions used to calculate the hydrogen concentration versus time after a DBA and the availability of the Supplementary Containment Purge System to provide the required safety function. The ITS Action requires the hydrogen control function be verified available within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> thereafter. This administrative verification will assure the safety function is maintained. The bases for operation of the recombiners indicates that if a design basis event occurs, it would take approximately 11 days after the accident for the hydrogen concentration to approach 3.5%. It is, therefore, reasonable South Texas Units 1 & 2 Page L - 7 Rev 0, 07/18/97

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STP ITS Conversion Attachm:nt 3 Discussion of Changes Section 3.6 - CONTAINMENT SYSTEMS TECHNICAL CHANGES LESS RESTRICTIVE to assume that the Inoperability of two hydrogen recombiners will not significantly Jeopardize the capability of the facility to respond to a design basis event. This change in ITS 3.6.7 is consistent with NUREG 1431.

L.17 The CTS 4.6.4.2 Surveillance Requirement to perform a hydrogen recombiner functional test every 6 months is revised to every 18 months is in accordance with NUREG.

1366. This change is considered acceptable due to the redundancy and proven high reliability of the system.

Hydrogen recombiner rperating experience has shown that functioria; test foi;utes are _ rare. This change in ITS 3.6.7 is l

consistent with NUREG 1431.

L.18 CTS 3.6.2.1 requires, with one train of Containment Spray inoperable, the system to be restored to OPERABLE status within 7 days. Proposed ITS 3.6.6, Action A, allows one train of containment spray to be inoperable for a period up to 28 days. Three trains of containment spray are currently required by TS. In the ITS, containment spray and containment coc!!ng RCFC are combined in LCO 3.6.6. By combining the two systems into one specification, NUREG-1431 relates the dependence of the systems in their function to remove energy from the containment atmosphere. With the required trains of centainment cooMag RCFC and two trains of containment spray operable, a significant portion of the containment energy removal capability remains available.

The 28 day Completion Time is a reasonable time for repairs and results in a low probability of a DBA occurring during this period of time. The Comoletion Time of 28 days is suonorted by the Aonlication of the Probabilistic Safety Assessment to the South Texas Project ITS.

L.19 CTS 3.6.2.3 requires, with one train of centainment ccc!!ng RCFC inoperable, the system to be restorxl to OPERABLE status within 7 days. Proposed ITS 3.6,6, Action A, allows one train of containment coc!!ng RCFC to be inoperable for a period up to 28 days. Three trains of containment cccling RCFC are currently required by TS. In the ITS, containment South Texas Units 1 & 2 Page L - 8 Rev. O, 07/18/97

STP ITS Conv:rsi:n Discussion of Changes Section 3.6 CONTAINMENT SYSTEMS TECHNICAL CHANGES LESS RESTRICTIVE spray and containmenkoohng RCfC are combined in LCO 3.6.6. By combining the two systems into one specification, NUREG 1431 relates the dependance of the systems in their function to remove energy from the containment atmosphere.

With the required trains of containment spray and two trains I

of eentainmenwoo4ng RCfC operable, a significant portion of the containment energy removal capability remains available. The 28 day Completion Time is a reasonable time for repairs and results in a low probability of a DDA occurring during this period of time. The Comotetion Time of 28 davs is sunnorted by the Armlication of the Probabilistic Safety Assessment to the South Texas Project ITS.

L.20 Four notes are added to the CTS 3.6.3 Actions for all Containment Isolation valves includinn containment nurge and exhaust valves. The notes are added in accordance with the NUREG 1431 LCO 3.6.3. Containment isolation Valves.

Notes :L) and 4 are discussed in two senarate administrative channes. The first Note provides an allowance to onen containment isolation valves reauired to be closed (excent for the 48" containment nurce/ exhaust valves) under administrative controls. This is accentable based on the administrative controls consistina of a dedicated operator at the valve in continupys communication with the control room. This control orovides nrotection eaulvalent to the automatic isolation system. The larne nurne/ exhaust valves are excluded due to size and the direct flow nath from inside containment to the outside.

L.21 CTS 4.6.3.2. 4.6.2.1.C. and 4.6.2.3.b are revised to include the nhrase "or actual" in reference to an automatic actuation sinnal which verifies that each subsystem actuates on a test (or simulated) automatic actuation sinnal. This allotys satisfactory automatic svstem actuations from actual sinnals to be used to fulfill the reauirements of the surveillance.

Onerability is adeouatelv demonstrated in either case since the subsystem itself cannot discriminate between " actual" or

" simulated" sinnals. Therefore this chance retained in ITS 3.6.6 is accentable and consistent with NUREG 1431.

South Texas Units 1 & 2 Page L - 9 Rev, 0, 07/18/97

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