ML20101R524
| ML20101R524 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 04/11/1996 |
| From: | ENTERGY OPERATIONS, INC. |
| To: | |
| Shared Package | |
| ML20101R522 | List: |
| References | |
| NUDOCS 9604160338 | |
| Download: ML20101R524 (4) | |
Text
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i REACTOR COOLANT SYSTEM OVERPRESSURE PROTECTION LIMITING CONDITION FOR OPERATION 3.4.12 Low temperature overpressure protection (LTOP) shall be OPERABLE 1
with each SIT irolated*, and:
Two LTOP relief valves with a lift setting of $430 peig, or a.
1 b.
The Reactor Coolant System depressurized with an RCS vent path 26.38 square inches, SIT isolation is only required when SIT pressure is greater than or equal to RCS pressure.
APPLICABILITY: MODE 4 with TC 52 2 0'F, MODE 5, MODE 6 with reactor vessel j
head in place.
ACTION:
l With one LTOP relief valve inoperable, restore the inoperable a.
valve to OPERABLE status within 7 days or depressurize and vent the RCS through a 26.38 square inch vent path within the next 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
b.
With both LTOP relief valves inoperable, depressurize and vent the RCS through a 26.38 square inch vent path within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
c.
With a SIT not isolated, isolate the affected SIT within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.
If required action is not met, either:
i (1) Depressurize the SIT to less than the RCS pressure within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, or (2) Increase ~ cold leg temperature to greater than or equal to 220'F within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
I d.
The provisions of Specification 3.0.4 are not applicable.
i SURVEILLANCE REQUIREMENTS 4.4.12.1 Verify both sets of LTOP relief valve isolation valves are open at least once per.72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> when the LTOP relief valves are being used for overpressure protection.
4.4.12.2 The RCS vent path shall be verified to be open at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> ** when the vent path is being used for overpressure protection.
4.4.12.3 Verify that each SIT is isolated, when required, once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
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ARKANSAS - UNIT 2 3/4-28 Amendment No.
9604160338 960411 PDR ADOCK 05000368 P
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l 4.4.12.4 No additional LTOP relief valve Surveillance Requirements other than those required by specification 4.0.5.
- Except when the vent path is provided with a valve which is locked, sealed, or otherwise secured in the open position, then verify this valve is open at least once per 31 days.
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ARKANSAS - UNIT 2 3/4-29 Amendment No.
REACTOR COOLANT SYSTEM BASES 3/4.4.12 LOW TEMPERATURE OVERPRESSURE PROTECTION SYSTEMS i
Low temperature overpressure protection (LTOP) of the RCS, including the j
reactor vessel, is provided by redundant relief valves on the pressurizer j
which discharge from a single discharge header. Each LTOP relief valve ig a direct action, spring-loaded relief valve, with orifice area of 6.38 in and a lift setting of 5430 psig, and is capable of mitigating the worst-case design basis pressurization event. The LTOP design basis event is a j
simultaneous injection of two HPSI pumps and all three charging pumps to the water-solid RCS.
The analyses assume that the safety injection tanks J
are either isolated or are depressurized.
The LTOP system, in combination with the RCS heatup and cooldown limitations of LCO 3.4.9.1 and administrative restrictions on RCP i
operation, provides assurance that the reactor vessel non-ductile fracture limits are not exceeded during the design basis event at low RCS temperatures. These non-ductile fracture limits are identified as LTOP pressure-temperature (P-T) limits, which were specifically developed to provide a basis for the LTOP system. These LTOP P-T limits, along with the LTOP enable temperature, were developed using guidance provided in ASME Code Section XI, Division 1, Code Case N-514 that mandates that "LTOP systems shall limit the maximum pressure in the vessel to 110% of the pressure determined to satisfy Appendix G, paragraph G-2215 of Section XI, Division 1".
The enable temperature of the LTOP isolation valves is based on any RCS cold leg temperature reaching 220'F (including a 20'F uncertainty).
Although each relief valve is capable of mitigating the design basis LTOP event, both valves are required to be opened below the enable temperature i
to meet the single failure criterion of NRC Branch Technical Position RSS I
5-2, unless an RCS vent path of 6.38 in (equivalent relief valve orifice area) or larger is. maintained.
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ARKANSAS - UNIT 2 B 3/4 4-12 Amendment No.
Arkansas Nuclear One, Unit 2
" Low Temperature Overpressure Protectio Pr ses ure-Temperature n
Limits for 21 Effective Full Power Years" l
(ABB-CE Engineering Report A-PENG-ER-004, Revision 00) i I
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