ML20077N246
| ML20077N246 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 08/07/1991 |
| From: | ENTERGY OPERATIONS, INC. |
| To: | |
| Shared Package | |
| ML20077N230 | List: |
| References | |
| NUDOCS 9108140267 | |
| Download: ML20077N246 (3) | |
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l PROPOSED TECilNICAL SPECIFICATION BASIS CllANGE p l os i c.0267 /10507 FDR ADOC' 0300031-'
p PDR
2.2 SAFETY LIMITS - REACTOR SYSTEM PRESSURE Applicability Applies to the limit on reactor coolant system pressure.
Ohlective To maintain the integrity of the reactor coolan; system and to prevent the release of significant amounts of fission product activity.
Specification 2.2.1 The reactor coolant system pressure shall not exceed 2750 psig when there are fuel assembiles in the reactor vessel.
2.2.2 The setpoint of the pressurizer code safety valves shall be in accordance with ASME, Boller and Pressurizer Vessel Code,Section III, Article 9, Summer 1968, EADRE The reactor coolant system (i) serves as a barrier to prevent radionuclides in the reactor coolant from reaching the atmosphere.
In the event of a fuel cladding failure, the reactor coolant system is a barrier against the release of fission products.
Establishing a system pressure limit helps to assure the integrity of the reactor coolant system.
Th.s maximum transient pressure allowable in the reactor coolant system pressure vessel under the ASME code,Section III, is 110 percent of design pressurr. (2) The maximum transient pressure allowable in the reactor coolant system piping, valves, and fittings under ANSI Section B31.7 is 110 percent of design pressure.
Thus, the safety limit of 2750 psig (110 percent of the 2500 psig design pressure) has been established. (2) The settings for the reactor high pressure trip (2355 psig) and the pressurizer code safety valves (2500 psig 11%) (*) have been established to assure that the reactor coolant system pressure safety limit is not exceeded. When testing the pressurizer code safety valves, t.he "as found" lif t setpoint may be 2500 psig +1,
-3%.
Ilowever, if found outside of a 11% tolerance band, they shall be reset to 2500 psig 1%.
The initial hydrostatic test la conducted at 3125 psig (125 percent of design pressure) to verify the -tegrity of the reactor coolant system. Additional assurance that the re ctor coolant system pressure does not exceed the safety limit is provided by setting the pressurizer electromatic relief valve at 2450 psig. (*)
REFERENCES (1) FSAR, Section 4 (2) FSAR, Section 4.3.11.1
{
(3) FSAR, Section 4.2.4 (4) FSAR, Table 4-1 Amendment No. 49,Jff, 10
BASES:
The plant is designed to operate with both reactor coolant loops end at least one reactor coolant pump per loop in operation, and maintain DNPR above 1.30 during all normal operations ar.d anticipated transients.(1)
Whenever the reactor coolant average temperature is above 280'F, single failure considerations require that two loops he operable.
The decay heat removal system suction piping is designed for 300 F thus, the system can remove decay heat when the reactor coolant system la below this temperature.
(2,3)
One pressurizer code safety valve is capable of preventing overpressurization when the reactor is not crit ical since its relieving capacity is greater than that required by the sum of the available heat sources which are pump energy, pressurizer heaters, and reactor decay heat.
(4) Both pressurizer code sa fety valves are required to be in service prior to criticality to conform to the system design relief capabilities.
The code safety valves prevent overpt essurn for a rod withdrawal accident.
(5) The pressurizer code safety valve lift setpoint shall be 2,500 psig 11 percent allowance for error and each valve shall be capable of relieving 300,000 lb/h of saturated steam at a pressure not greater than 3 percent above the set pressure. When testing the pressurizer code safety valves, the "as found" lift setpoint may be 2500 psig
+1,
-3 percent.
Ilowev e r, if found outside the il percent tolerance band, they shall be reset to 2500 psig il percent.
The internals vent valves are provided to relieve the pressure generated by steaming in the core following a LOCA so that the core remains sufficiently covered.
inspection and manual actuation of the internal vent valves (1) ensure operability, (2) ensure that the valves are not open during normal operation, and (3) demonstrata that the valves begin to open and are fully open at the forces equivalent to the dif ferential pressures assumed in the safety analysis.
The reactor coolant vents are provided to exhaust noncondensible gases and/or steam from the primary system that could inhibit natural circulation core cooling. The operability of at least one reactor coolant system vent path from the reactor vessel head, the reactor coolant system highpoints, and the pressurizer steam space ensures the capability exists to perform this function.
The valve redundancy of the vent paths serves to minimize the probability of inadvertent actuation and breach of reactor coolant pressure boundary while ensuring that a single f a il u re of a vent valve, power supply, or cor,r ol syst em does iat prevert isolation of the vent path. Testing rs,uirements are covered in Section 4.0 for the class 2 valves and Table 4.'-2 for the ve'nt paths. These are consistent with ASME Section XI and Iter II.B.1 of NUREG-0737, " Clarification of TMI Action plan Requirements," l'/10.
REFERENCEE (1) FSAR, Tables 9-10 and 4-3 through 4-7 (2) FSAR, Section 4.2.5.1 and 9.5.2.3 (3) FSAR, Section 4.2.5.4 (4) FSAR, Section 4.3.10.4 and 4.2.4 (5) FSAR, Section 4.3.7 Amendment No. ZJ, E6, 95, 17
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