ML19338E080

Forwards Response to Bulletins & Orders Task Force Recommendations Re Auxiliary Feedwater Sys.Response Supplements Info Transmitted in 800813 Ltr

ML19338E080
Person / Time
Site:	McGuire, Mcguire
Issue date:	09/18/1980
From:	Parker W DUKE POWER CO.
To:	Harold Denton, Youngblood B Office of Nuclear Reactor Regulation
References
NUDOCS 8009240489
Download: ML19338E080 (7)

Text

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c' DUKE POWER COMPANY Powsm Duttonwo 422 Socrn Cucacu Srazer. CnAar.orTr. N. C. cea4a mwaa o. ananza.sa. September. 18, 1980 WCf Pettigte.f Ytit**Ch t: A*ta 704 Sita. Poocucwon 373 4083 Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C. 20555 Attention: Mr. B. J. Youngblood, Chief Licensing Projects Branch No. 1 Re: McGuire Nuclear Station Docket Nos. 50-369, 50-370

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Dear Mr. Denton:

Attached is a brief discussion of each of the Bulletins and Orders Task Force recommendations on auxiliary feedwater systems as they app 1.y to McGuire Nuclear Station. This information supplements that transmitted by my letter of August 13, 1980.

If you have additional questions regarding this matter, please advise.

Ve truly yours, ,

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William O. Parker, Jr.g N v

GAC:scs Attachment

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MCGUIRE NUCLEAR STATION RESPONSE TO BULLETIN AND ORDERS TASK FORCE RECOMMENDATIONS Shoct-Term Recommendations Recommendation GS-1 The licensee should propose modifications to the Technical Specifications to limit the tina that one AFW system pump and its associated flow train and essential instrumentation can be inoperable. The outage time limit and sub-sequent action time should be as required in current Standard Technical Specifications; i.e., 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> and 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, respectively.

Response

McGuire Nuclear Statica has Standard Technical Specifications and as such already has these requirements included in the Technical Specifications.

Recommendation GS-2 The licensee should lock open single valves or multiple valves in series in the AFW system pump suction piping and lock open other single valves or multiple valves in series that could interrupt all AFW flow. Monthly inspections should be performed to verify that these valves are locked and in the open position.

These inspections should be proposed for incorporation into the surveillance requirements of the plant Technical Specifications. See Recommendation GL-2 for the longer-term resolution of this concern.

Response

All manual valves in the auxiliary feedwater flowpath are checked monthly to verify that they are locked open. This requirement is included in the McGuire Technical Specifications.

Recommendation GS-3 The licensee should reexamine the practice of throttling AFW system flow to avoid water hammer.

The licensee shculd verify that the AFW system will supply on demand sufficient initial flow to the necessary steam generators to assure adequate decay heat rc=ovsl follcwing loss of main feedwater flow and a reactor trip from 1007. power. !

In cases where this reevaluation results in an increase in initial AFW system l flow, the licensee should provide sufficient information to demonstrate that the required ham =er, initial AFW system flow will not result in plant damage due to water l i

Response

Auxiliary feedwater flow is not thrott led initially to prevent water hammer. The required flow rate is available within 60 seconds following the initiating event.

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Recommendation GS-4 Emergency. procedures for transferring to alternate sources of AFW supply should be available to the plant operators. These procedures should include criteria to inform the operators when, and in what order, the transfer to alternate water sources should take place.

Response

Transfer of the auxiliary feedwater supply from the normal to the safety grade assured supply occurs automatically when suction pressure drops below an acceptable limit. The instrumentation and controls utilized in the switchover 2

logic are-safety grade.

Recommendation GS-5 The as-built plant should be capable of providing the required AFW flow for at '

least two hours from one AFW pump train, independent of any AC power source.

Response

The auxiliary feedwater system at McGuire is capable of automatic initiation and of providing the required flow for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> independent of any AC power source.

This is accomplished by means of the turbine-driven auxiliary feedwater pump and DC motor-operated / solenoid valves at appropriate locations in the system.

Recommendation GS-6 The licensee should confirm flow path availability of an AFW system flow train that has been out of service to perform periodic testing or maintenance as follows:

(1) Precedures should be implemented to require an operator to deter-mine that the AFW system valves are properly aligned and a second operator to independently verify that the-valves are properly aligned.

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(2) The licensee should propose Technical Specifications to assure that, prior to plant startup following an extended cold shutdown, a flow

' test would be performed to verify the normal flew path from the primary AFW system water source to the steam generators. The flow test should be conducted with AFW system valves in their normal alignment.

! Response e

(1) Procedures will be developed to provide for. double verification of the auxiliary feedwater system alignment following maintenance activities.

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For normal periodic testing of the system, no realignment of manual valves is required so no verification of system status is necessary.

(2) McGuire Nuclear Station has the latest version of the Standard Technical Specifications which provide adequate assurance of the operability of the auxiliary feedwater system.

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Recommendation GS-7 The licensee should verify that the automatic start AFW system signals and associated circuitry are safety-grade.

Response

The McGuire auxiliary feedwater system employs safety-grade automatic initia-tion signals and circuits. Automatic initiation of the system is discussed in the Final Safety Analysis Report, Section 7.4.1.1.

Recommendation GS-8 The licensee should install a system to automatically initiate AFW system flow.

Response

See response to Recommendation GS-7.

Additional Short-Term Recommendations Recommendation The licensee should provide redundant level indication and low level alarms in the control room for the AFW system primary water supply, to allow the operator to anticipate the need to make up water or transfer to an alternate water supply and prevent a low pump suction pressure condition from occurring. The low level alarm setpoint should allow at least 20 minutes for operator action, assuming that the largest capacity AFW pump is operating.

Response

As noted in the response to Recommendation GS-4, the McCuire design utilizes an automatic transfer of the auxiliary feedwater supply to the assured supply, the nuclear service water system. In addition to this, single channel, non-safety-grade level indication and low level alarms are provided in the control room for each of the normal auxiliary feedwater sources (upper surge tank, condenser hot-well and filtered water storage tank).

Recom=endation The licensee should perform a 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> endurance test on all AFW system pumps, if such a test or continuous period of operation has not been accomplished to date.

Following the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> pump run, the pumps should be shut down and cooled down and then restarted and run for one hour. Test acceptance criteria should include demonstrating that the pumps remain within design limits with respect to bearing /

bearing oil temperatures and vibration and that pump room ambient conditions (temperature, humidity) do not exceed environmental qualification limits for safety-related equipment in the room.

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Response

It is our understanding that the Staff has modified this recommendation to perform a 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> endurance test on all auxiliary feedwater pumps in lieu of the 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> test. The notor-driven auxiliary feedwater punps were cun several days during the hot functional test period. The exact time period and systee configuration will be documented. The turbine-driven auxiliary feedwater pump has not been run for an extended period. A 48-hour test of this pump will be performed after the heatup following initial fuel loading.

Recommendation The licensee should implement the following requirements as specified by Item 2.1.7.b on page A-32 of NUREG-0578:

(1) Safety-grade indication of AFW flow to each steam generator should be provided in the control room.

(2) The AFW flow instrument channels should be powered frot the

" emergency buses consistent with satisfying the emergency power diversity requirements for the AFW system set forth in Auxiliary Systems Branch Technical Position 10-1 of the Standard Review Plan, Section 10.4.9.

Response

This recommendation has been implemented as indicated by our response to item II.E.1.2 from NUREG-0694 contained in Duke Power Company " Response to TMI Concerns" submitted initially on May 23, 1980.

Recommendation Licensees with plants which require local manual realignment of valves to conduct periodic tests on one AFW system train and which have only one remain-ing AFW train available for operation should propose Technical Specifications to provide that a dedicaced individual who is in communication with the control room be stationed at the manual valves. Upon instruction from the control room, this operator would re-align the valves in the AFU system from the test mode to its operational alignment.

Response

The auxiliary feedwater system design is such that no manually operated valvea need to be repositioned during periodic testing of the system. Those valves which must be repositioned can be operated from the control room. In the event the system is automatically actuated, these valves will be actuated to their

" safety" position.

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Long-Term Recommendations Recommendation GL-1

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For plants with a manual starting AFW system, the licensee should install a system to automatically initiate the AFW system flow. This system ar,d associated Lutomatic initiation signals should be designed and installed to meet safety-grade requirements. Manual AFW system start and control capability should be retained with manual start serving as backup to automatic AFW system 1

initiation.

Response

See response to Recommendation GS-7.

Recommendation GL-2 Licensees with plant designs in which all (primary and alternate) water supplies to the AFW systems pass through valves in a single flow path should install redundant parallel flow paths (piping and valves).

Response

The McGuire auxiliary feedwater system design has redundsnt flow paths via redundant pumps, valves and piping.

Recommendation GL-3 '

At least one AFW system pump and its associated flow path and essential instrumentation should automatically initiate AFW system flow and be capable of being operated independently of any AC power source for at least two hours.

Conversion of DC power to AC power is acceptable.

Response

See response to Recommendation GS-5.

Recommendation GL,4

Licensees having plants with unprotected normal AFW system water supplies should evaluate the design of their AFW systems to determine if automatic protection cf the pumps is necessary following a seismic event or a tornado.

The time available before pump damage, the alarms and indications available to the control room operator, and the time necessary for assessing the problem i and taking action should be considered in determining whether operator action can be relied on to prevent pump damage. Consideration should be given to providing pump protection by means such as automatic switchover of the pump suctions to the alternate safety-grade source of water, automatic pump trips on low suction pressure, or upgrading the normal source of water to meet seismic Category 1 and tornado protection requirements.

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Response

Auxiliary feedwater system pumps are protected by automatic switchover to the safety-grade source of water following any loss of normal source resulting from natural phenomena or other causes.

Recommendation GL-5 The licensee should upgrade the AFW system automatic initiation signals and circuits to meet safety-grade requirements.

Response

See response to Recommendation CS-7.