ML19340C817

Final Deficiency Rept,Initially Reported 800407,re Environ Qualifications of Valve Room Class IE Instruments. Differential Pressure Switches Will Be Modified to Upgrade Qualification Level & Transmitters Will Be Replaced

ML19340C817
Person / Time
Site:	Sequoyah
Issue date:	12/10/1980
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
10CFR-050.55E, 10CFR-50.55E, MCR-SQN-EEB-800, NCR-SQN-EEB-800, NUDOCS 8012170515
Download: ML19340C817 (5)

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400 Chestnut Street Tower II December 10, 1980 Mr. James P. O'Reilly, Director Office of Inspectim and Enforcement U.S. Nuclear Regulatory Conmission Region II - Suite 3100 101 Marietta Street i Atlanta, Georgia 30303 \

Dear Mr. O'Reilly:

SEQUOYAH NUCLEAR PLANT UNIT 2 - ENVIRONMENTAL QUALIFICATION OF CLASS IE INSTRUMENTS IN THE VALVE 200M - NCR'S SQN EEB 8003 AND SQN EC3 8004 -

FIMAL RE?CRT The subject deficiency us initially reported tc NRC-0IE Inspector M. Tho=as en April 7,1980, in accordance with 10 CFR 50.55(e). Interim reports were submitted on May 7, July 7, September 12, and October 13, 1980. Enclosed is our final mpcet.

If you have any questions, please get in touch with D. L. Lambert at FTS 857-2581.

Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills, Manager i

Nuclear Regulation and Safety i

Enclosure l cc: Mr. Victor Stello, Director (Enclosureb/

Office of Inspection and Enforcement

( U.S. Nuclear Regulatory Connaission i Washington, DC 20555 I

i OfY S i/

i 80222705/5, 3

! ENCLOSURE i

SEQUOYAH NUCLEAR PLANT UNIT 2 ENVIROR! ENTAL QUALIFICATION OF CLASS IE INSTRUMENTS IN THE VALVE ROOM NCR NO. SQN EEB 8003 AND NCR NO. SQN EEB 8004 10 CFR 50.55(e) ..

FINAL REPORT Description of Deficiency i

l Nonconforming condition SQN EEE 8003 concerns the steam generator pressure transmitters (Foxboro Model EllGM) which are located in the valve rooms at Sequoyah Nuclear Plant. According to the latest revision of the FSAR, the transmitters are not qualified for the worst case environment result-

) ing from a high energy line break in the vcive room. The detrimental environmencal aspect is the temperature. FSAR Table 3.11-2 indicates that a peak temperature of 296 F inside the valve room is possible, while the transmitters in question are qualified to only 130 F.

As a result of this condition, all other instrumentation inside the valve rooms has been evaluated. Those instruments that are not qualified which might pose a safety concern are documented in NCR No. SQN EEB 8004.

These are:

1. Main steam pressure transmitters (one per loop)

2. Level solenoid valves which route control air to level control valves which regulate water from the turbine-driven auxiliary feedwater pump to steam generators 1 and 4 (total of two)

3. Steam flow control valve to auxiliary feed pump tyrbine (total of

- four) and corresponding handswitches

4. Steam generator main feedwater isolation valve (total of four) and corresponding handswitches

5. Pressure switches for flow to auxiliary feed pump turbine

6. Pressure switches which detect an auxiliary feedwater pipe break

! (total of six)

7. Cable types C?J, CPJJ, and PJJ used in the valve rooms l

Safety Imolications l

l SCNEEB8003 These steam generator pressure transmitters are designated as post-accident monitoring (PAM) equipment. Because loss of PAM instrumentation is detrimental to the operator's ability to take appropriate action to mitigate an accident, this -

condition could have affected plant safety.

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, SCNEE33004 TVA's evaluation of the equipment covered by this NCR is listed below.

1. Transmitters PT-1-1C, -8C, -19C, and -26C. PT-1-1C, i -8C, -19C, and -26C are used for auxiliary control of atmospheric relief valves'en the =ain steam headers.

These PT*3 are only lined up when control is in the auxiliary code and are not required to operate for the accident. Therefore, this condition could not have i

adversely affected plant safety.

2. Solenoid valves LSV-3-174 and -175. LSV-3-174 and 5 are used for flow control to steam generator (SG) 6 1 and SG No. 4 through turbine-driven auxiliary feedwater (TDAFW) headers. Failure of these solenoids would result in one of two modes. Either the associated valve would receive air or air would be tlocked resulting in valve isolation. Isolation would be an acceptable failure. If air is being received, the valve is modulating and causing a less desirable situation. However, manual centrol of AFW is available, and the valve can be isolated from the =ain control room. Isolation to SG 1 and 4 is acceptable since at least TDAFW would be provided to intact SG's 2 and 3 3 & 4. Motor-operated Valves (MOV) - FCV 1-15, 16, 17, 18; FCV 3-33, 47, 87, 100. These MOV's were originally found to have inadequate documentation to justify operation in the accident te=perature environment. The vendor has now analyzed the subject equipment for the higher te:peratures and has confirmed, by letter, that the valves under postulated accident conditions will perform their intended function. Therefore, this

. condition could not have adversely affected plant safety.

Handswitches: HS-1-15B, 16B, 17B, 18B, HS3-33B, 47B, 87B, 1003 These handswitches are used for. testing purposes and are not required to operate in the accident environment. However, spurious signals caused by failure of these switches could cause the valves to go to an undesirable position which could affect plant safety.

5. PDIS-1-17 and 18.

Case 1 - Failure of the PDIS is postulated to cause isolation of the associated FCV's for the auxiliary feed pump turbine.

- - _ .. -- --. ~ ... - -_. ,

Consider the high energy line treak (HELB) associated with SG No. 4 and a failure of motor-driven auxiliary feedwater (MDAFW) pump 1A-A. The result is a total loss of AFW except for the MDAFW pump 13-3 feeding the faulted SG No. 4 and intac,t SG No. 3 This is unacceptable feedwater flow which could adversely affect plant safety.

A similar situation would exist with a faulted SG No.1 and failure of MDAFW pump 13-3.

Case 2 - Failure of.the PDIS is postulated to.not cause isolation of the associated FCV's for the auxiliary feed pump turbine.

PDIS-1-17 and -18 are not required to operate since they are used only t0 indicate and icolate breaks in the TDAFW pump rect Or high flow in the TDAF'n' pump line. Therefore, TDAFW would be available to all SG's. Also, a failed or faulty indication from the PDIS would not cause the operator to take improper action since it provides local indication only. This failure code could not have adversely affected plant safety.

6. PS-3-160A&B, 165A&B, 1403, and 150B Case 1 - Failure of PS's is postulated to cause associated LCV's to close. Consider the high energy line break (HEL3) associated with SG No. 4 and a failure of cotor-driven auxiliary feedwater (MDAFW) pu:p 1A-A. 'The result is a total loss of AFW except for the MDAFW pu=p 13-3 feeding the faulted SG No. 4 and intact SG No. 3 This is unacceptable feedwater flow which could adversely affect plant safety. This is the same result as described above in Case 1 of

( Item 5.

Case 2 - Failure of PS's is postulated to not cause associated LCV's to close. The faulted SG would receive TDAFW as well as the other SG's. The operator can isolate flow to the faulted SG at 10 minutes.

Therefore, this mode is considered acceptable.

The PS's do not provide any indication er alarm, and therefore their failure would not cause i= proper

! operator action.

7. Internal wiring (cable types CPJ, CPJJ, and PJJ) to

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junction boxes 3032, 3061, 3066, 3063, 3062, 3069, 2890, 2891, 2857, and 2358.

These cables were originally suspected to be not qualified for the accident environment. We have since determined, from review of vender infor=ation, that the CPJ and CPJJ cables are adequately qualified.

Cable type PJJ is not qualified to the expected environ =ent. Failure of this cable could cause the loss of safety-related equipment which could adversely affect plant safety.

Corrective Action SONEEE8003 The steam generator pressure transmitters will be replaced with transmitters which have been qualified for operation in the expected environment.

f Item 3&4: The handswitches will be removed frc= service during normal operation so that failure will not' affect operation of the valves.

SONEEE8004 Item 5: The differential pressure switches will be modified to upgrade the level of qualification to meet the calculated accident environ =ent.

Item 6: Two of the pressure switches will be moved out of

the harsh environment. This will result in acceptable AFW flow for the postulated event.

Item 7: The cables which are not qualified to the expected environment (type PJJ) will be replaced.

All corrective actions will be completed before fuel load.

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