ML19325D462

Special Rept 89-11 Re Noncompliance W/Requirements of License Condition Section 2.C.13.c Re 10CFR50,App R.Caused by Inadequate Design Review in Area of Power Supplies to Main Control Room Recorders.Roving Fire Watches Established

ML19325D462
Person / Time
Site:	Sequoyah
Issue date:	10/17/1989
From:	Michael Ray TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
89-11, NUDOCS 8910240188
Download: ML19325D462 (4)

Text

ry, u

9 o .

f:

.., TENNESSEE VALLEY AUTHORITY [

CH ATTANOOGA. TENNESSEE 37401 SN 157B Lookt,ut Place 00T 171989  :

U.S. Nuclear Regulatory Commission ATTN: Doc.Jment Control Desk Washington, D.C. 20555 Gentlemen:

TE G ESSEE VALLEY AUTHORITY - SEQUOYAH NUCLEAR PLANT UNITS 1 AND 2 - DOCKET NOS. 50-327 AND 50-328 - FACILITY OPERATING LICENSES DPR-77 AND 79 - SPECIAL

REPORT 89 APPENDIX R The enclose.1 special report provides details concerning noncompliance with requirements of Unit 2 License Condition Section 2.C.13.c of the Unit 2 Facility Operating License. The noncompliance conditions are appilcable to i both Units 1 and 2. These conditions are reported in accordance with License Condition 2.H.

If you have any questions concerning this submittal, please telephone -

M. A. Cooper at (615) 843-6651.

Very truly yours, TENNESSEE VALLEY AUTHORITY I/h cq ,

Mahageh,NuclearLicensingand '

Regulatory Affairs fnclosure L cc (Enclosure): '

l Ms. S. C. Black, Assistant Director I i'or Projects TVA Projects Division U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Mr. B. A. Wilson, Assistant Director for Inspection Programs TVA Projects Division U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323 l

NRC Resident Inspector Sequoyah Nuclear Plant 2600 Ioou Ferry Road Soddy Daisy, Tennessee 37379 d

r I\

891024018e 891017 An Equal Opportunity Employer

(

PDR ADOCM 05000327 l S PNV

y -_

h .

e Sequoyah Nuclear Plant Units 1 and 2 i

14-Day.Folicw-up Rep (.t Special Report 89-11 p Description of Condition

< 1 This special report addresses the requirements of Unit 2 License Condition

, Section 2.C.13.c of the Unit 2 Facility Operating License regarding ,

i

^

10 CFR 50, Appendix R. These conditions are reported in accordance with

• License Condition 2.H and are applicable to both Units 1 and 2.

Condition Adverse to Quality Report (CAQR) SQP890532 was issued on October 3, 1989, documenting a noncompliance with 10 CFR 50, Appendix R, Section III.G.2 requirements. .

Section III.G.2 requires redundant safety shutdown components to be separated from each other by one of the following methods. .

1. Separation of cables and equipment and associated nonsafety circuiti of ';

redundant trains by a fire barrier having a three-hour rating.

2. Separation of cables and equipment and associated nonsafety circuits of redundant trains by a horizontal disttnce oi more than 20 feet with no intervening combustible.or fire hazards. In addition, fire d$tectors and an automatic fire suppression system shall be installed in the fire area.

3. Enclosure of cables and equipment and associated nonsafety circuits of one redJndant train in a fire barrier having a one-hour rating. In addition, fire detectcrs and an automatic fire suppression system shall be installed in the fire area.

Contrary to Section III.G.2, electrical Cables IPV16I, IPV135II, 2PV161, and 2nV1351! required to supply 120-volt alternating current vital power for t reactor coolant system (RCS) hot and cold leg temperature loor; do not meet the separation requirements. The RCS temperature loops are 1 and 2-T-68-1,

-18, -24, -41, -43, -60, -65, and -83, which feed the main control room RCS temperature recorders. During the root cause investigation, an additional ,

interaction was identified on October 6, 1989. The additional interaction involved electrical Cables IPM4633, 2PM4633, IPV161, IPV13511, 2t"/161, and 2PV135II, involving the three RCS pressure instrument Loops 1 and 2-P-68-342,

-69, and -66. These instrument loops are identified in TVA's calculation identifying equipment required for safe shutdown in accordance with 10 CFR 50, Appendix R.

The RCS temperature loop interactions for Unit 1 are located between the Q-line wall and R-line from Column Aa to A5 on Elevation 714.0 in the auxiliary building (Final Safety Analysis Report (FSAR), Figure 1.2.3-4).

The Unit 2 interactions are located between the Q-line wall and R-line from Column A4 to A12 on Elevation 714.0 in the auxiliary building. The RCS

< pressure interaction for Unit 1 is located between the Q-line wall and S-line from Column A3 to A5 on Elevation 714.0 in the cuxiliary building (FSAR, Figure 1.2.3-4). The Unit 2 interaction is located between the Q-line wall and R-line from Column All to A13 on Eleve. tion 714.0 in the auxiliary building. These areos are provided with fire detection and an automatic fire suppression system. Additionally, these areas are and have been included in the existing hourly roving fire watches.

r- .

, . 4 s ,

This condition was identified during a review of a postaccident monitoring upgrade modification Involving the same circuits. " e design change was being reviewed for its impact on the Appendix R analysis Mcause the instrument loops involved were required for safe shutdown in the event cf a fire. During this review, it was determined that the power supplies to the ra-ks had not been identified or sutecquently traced for potential cable interactions.

Cause of Condition The root cause of this event has been attributed to an inadequate design review in the specific area of power suppliec to main control room recorders required for safe shutdown. There was a breakdown in the issuance of the electrical block diagram calculations in that al'. the required power supply cables were not properly identified and evaluated. The original calculation was based on the engineering judgement that only one power supply was required for the instrument loops in question. When the powe" iupply to a recorder was identified and its availability confirmed, a further review was not considered necessary to ensure that the instrument .ack power supply was also guaranteed. The incorrect engineering judgement was not documented. The '

procedure used by Nuclear Engineering at the time required an independent review to be performed; however, the review was not adequate.

Analysis of Condition As a result of the identified interactions, there are no plant systems or components considered inoperable or incapable of performing their function.

koving (one-hour) fire watches had already been established for the auxiliary building areas as a result of previously identified Appendix R deficiencies.  :

The roving fire watches, coupled with the existing fire detection and suppression system, provide assurance that a fire in these areas will be identified and apprnpriate corrective action taken to ensure safe operation.

Therefore, there are no Puclear safety implications as a result of this problem.

Corrective Actions As a result of the reviews of the main control room Apnendix R recorders and indicators, it has been determined that this condition is limited at this time to the main control room recorders. However, TVA is continuing to evaluate the potential gener'c implications in follow-up to the CAQR.

In accordance with limiting Condition for Operation (LCO) 3.7.12 on fire carriers and an NRC letter to TVA dated August 10, 1984, roving fire watches are in effect for the affected areas. These fire watches will continue until the Appendix R requirements are met.

The interactions ider cified will be corrected by the end of the Cycle 4 refueling outage for the respective units. Additionally, the documentation problems associated with the electrical block diagrams and the Appendix R sketch (ARSK) drawings shculd be corrected in this same timeframe. As an interim corrective accion, the as-designed ARSK drawings have been annotated identifying the interactions.

w

m r

'a p

i-

• The present Nuclear Engineering procedures now include a requirement that engineering judgements be documented in the body of the calculation.

Therefore, if the decision'to include only one power supply had been documented with the basis of the calculation, thero is a greater likelihood that the error would have been caught. Based on changes to the procedures, no further action is required.

Additional Inform tlon Additional Appendix R interactions have been identified in Docket No. 50-3E7, Facility Operating License DPR-77, Special Report 88-14, Appendix R, and 1 -Docket No. 50-328, facility Operating License DPR-79, Special Report 84-08, Appendix R.

Commitments I;

1. The interactions identified will ce corrected by the end of the Cycle 4 ,

refueling outage for the respective units. t

2. Additionally, the docunentation problems associated with the electrical block diagrams and the /,RSK drawings will be corrected by the end of the Cycle 4 refueling outage for the respective units.

l l

l 1

l l