ML20211R000

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Proposed Tech Spec Changes,Allowing Removal of Ctr Control Rod Assembly & Addition of Radcal Vessel Level Probes During Seventh Refueling Outage
ML20211R000
Person / Time
Site: Arkansas Nuclear Entergy icon.png
Issue date: 07/18/1986
From:
ARKANSAS POWER & LIGHT CO.
To:
Shared Package
ML20211Q983 List:
References
NUDOCS 8607280077
Download: ML20211R000 (6)
v • d • e


Text

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G ATTACHMENT 2 PROPOSED CHANGES T0 ANO-1 TECHNICAL SPECIFICATIONS eG 8607280077 860718 PDR ADOCK 05000313 p PDR

3.1.9 Control Rod Operation Specification 3.1.9.1 The concentration of dissolved gases in the reactor coolant shall be limited to 100 std. cc/ liter of water at the reactor vessel outlet temperature.

3.1.9.2 Allowable combinations of pressure and temperature for control rod operation shall be to the left of and above the limiting pressure versus temperature curve for a dissolved gas concentration of 100 std. cc/ liter of water as shown in Figure 3.1.9-1.

3.1.9.3 In the event the limits of Specifications 3.1.9.1 or 3.1.9.2 are exceeded, the vessel level instrument vent shall be checked for accumulation of undissolved gases. The temperature, pressure and dissolved gas concentration shall be restored to within their limits within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or be in at least Hot Standby within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

Bases By maintaining the reactor coolant temperature and pressure as specified above, any dissolved gases in the reactor coolant system are maintained in solution.

Although the dissolved gas concentration is expected to be approximately 20-40 std. cc/ liter of water, the dissolved gas concentration is conservatively assumed to be 100 std. cc/ liter of water at the reactor vessel outlet temperature.

The limiting pressure versus temperature curve for dissolved gases is determined by the equilibrium pressure versus temperature curve for the dissolved gas concentration of 100 std. cc/ liter of water. The equilibrium total pressure is the sum of the partial pressure of the dissolved gases plus the partial pressure of water at a given temperature. The margin of error consists of the maximum pressure difference between the pressure sensing tap and lowest pressure point in the system, the maximum pressure gage error, and the pressure difference due to the maximum tempe=ature gage error.

If either the maximum dissolved gas concentration (100 std. cc/ liter of water) is exceeded or the operating pressure falls below the limiting pressure versus temperature curve, the vessel level instrument vent should be checked for accumulation of undissolved gases.

Amendment No. 57 32

4.7.2 Control Rod Program Verification (Group Vs Core Positions)

Applicability Applies to surveillance of the control rod systems.

Objective To verify that the designated control rod (by core position) is operating in its programmed functional position and group (rods 1 through 12, group 1-8).

Specification 4.7.2.1 Whenever the control rod drive patch panel is locked (after test, reprogramming, or maintenance) each control rod drive mechanism shall be selected from the control room and exercised by a movement of two inches or less to verify that the proper rod has responded as shown on the unit computer printout or on the input to the computer for that rod.

4.7.2.2 Whenever power or instrumentation cables to the control rod drive assemblies atop the reactor or at the bulkhead are disconnected or removed, an independent verification check of their reconnection shall be performed.

4.7.2.3 Any rod found to be improperly programmed shall be declared inoperable until properly programmed.

Bases Each control rod has a relative and an absolute position indicator system.

One set of outputs goes to the plant computer identified by a unique number associated with only one core position. The other set of outputs goes to a programmable bank of 68 edgewise meters in the control room. In the event l that a patching error is made in the patch panel or connectors in the cables leading to the control rod drive assemblies or to the control room meti.r bank are improperly ransposed upon reconnection, these errors and I transpositions will be discovered by a comparative check by (1) selecting a specific rod from one group (e.g., rod 1 in regulating group 6), (2) noting that the program-approved core position for this rod of the group, (3) exercise the selected rod, and (4) note that (a) the computer prints out

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j both absolute and relative position response for the approved core position (b) the proper meter in the control room display bank in both absolute and relstive meter positions. This type of comparative check will not assure detection of improperly connected cables inside the reactor building. For these, (Specification 4.7.2.2) it will be necessary for a responsible person, other than the one doing the work, to verify by appropriate means

, that each cable has been matched to the proper control rod drive assembly.

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5.3 REACTOR Specification 5.3.1 Reactor Core 5.3.1.1 The reactor core contains approximately 93.1 metric tons of slightly enriched uranium dioxide pellets. The pellets are encapsulated in Zircaloy-4 tubing to form fuel rods. The reactor core is made up of 177 fuel assemblies. Each fuel assembly contains 208 fuel rods. (1,2) 5.3.1.2 The reactor core approximates a right circular cylinder with an equivalent diameter of 128.9 inches and an active height of 144 inches. (2) 5.3.1.3 The average enrichment of the initial core is a nominal 2.62 weight percent of 23sU. Three fuel enrichments are used in the initial core. The highest enrichment is less than 3.5 weight percent 235U.

5.3.1.4 There are 60 full-length control rod assemblies (CRA) and 8 axial power shaping rod assemblies (APSRA) distributed in the l reactor core as shown in FSAR Figure 3-60. The full-length CRA contain a 134-inch length of silver-indium-cadmium alloy clad with l stainless steel. The APSRA contain a 36-inch length of silver-indium-cadmium alloy.(3) 5.3.1.5 The initial core has 68 burnable poison spider assemblies with similar dimensions as the full-length control rods. The cladding is Zircaloy-4 filled with alumina-boron and placed in the core as shown in FSAR Figure 3-2.

5.3.1.6 Reload fuel assemblies and rods shall conform to the design and evaluation described in FSAR and shall not exceed an enrichment of 3.5 percent of 23sU.

5.3.2 Reactor Coolant System 5.3.2.1 The reactor coolant system is designed and constructed in accordance with code requirements.(4) 5.3.2.2 The reactor coolant system and any connected auxiliary systems exposed to the reactor coolant conditions of temperature and pressure, are designed for a pressure of 2500 psig and a temperature of 650 F. The pressurizer and pressurizer surge line are designed for a temperature of 670 F.(5) 5.3.2.3 The reactor coolant system volume is less than 12,000 cubic feet.

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O ATTACHMENT 3 DETAILED DESCRIPTION OF PROPOSED CHANGES TO ANO-1 TECHNICAL SPECIFICATIONS e

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i DETAILED DESCRIPTION OF PROPOSED CHANGES TO ANO-1 TECHNICAL SPECIFICATIONS

a. Technical Specification 3.1.9.3: Reference to center control rod drive mechanism is changed to vessel level instrument vent.

The purpose of this change is to delete the reference to the center control rod drive mechanism (CRDM) for the checking for accumulation of dissolved gases. The vessel level instrument vent will serve this purpose after being installed during the ANO-1 seventh refueling outage (1R7) which is scheduled to begin August 22, 1986.

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b. Technical Specification 3.1.9 Bases: Reference to center CRDM in last sentence is changed to vessel level instrument vent.

The purpose of this change is identical to that described in a. above.

c. Technical Specification 4.7.2 Bases: Second sentence is changed to read ".. 68 edgewise meters in the control room."

The purpose of this change is to reflect the correct number of edgewise meters after removal of the center control rod assembly during 1R7.

d. Technical Specification 5.3.1.4: First sentence is changed to read

, "There are 60 full-length control assemblies (CRA) and 8 axial power shaping rod assemblies (APSRA) distributed in the reactor core as shown in FSAR Figure 3-60."

The purpose of this change is to decrease by one the number of CRAs referred to in the specification in order to reflect the removal of the center CRA. The purpose of changing the referenced FSAR figure number from 3-59 to 3-60 is to reflect the correct FSAR figure.

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