IR 05000029/1979014

IE Insp Rept 50-029/79-14 on 791107.No Noncompliance Noted. Major Areas Inspected:Followup on Licensee Corrective Action for Potential Degradation of Safeguards Bus Voltage Reported in LER 79-26

ML19257C926
Person / Time
Site:	Yankee Rowe
Issue date:	12/02/1979
From:	Lazarus W, Martin T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:
Shared Package
ML19257C923	List: IR 05000029/1979014 ML19257C922
References
50-029-79-14, 50-29-79-14, NUDOCS 8001310089
Download: ML19257C926 (3)

Text

9 r

.

.

U.S. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT Region I Report No. 50-29/79-14 50-29 Docket No.

C DPR-3

--

License No.

Priority Category Licensee: Yankee Atomic Electric Company 20 Turnpike Road Westborough, Massachusetts 01581 Facility Name: Yankee Nuclear Power Station (Yankee-Rowe)

Rowe, Massachusetts Inspection at:

Inspection conducted: Nove ber 7, 1979 Inspectors:

eF M 4e e

//

Mr. W(.fazaru@eactor Inspector date signed date signed date signed Approved by:

/2/.a./pp T. T. Martin, Chief, Reactor Projects date signed Section No. 3, R0 & NS Branch Inspection Summary:

Inspection on November 7, 1979 (50-29/79-14)

Areas Inspected:

Special unannounced inspection by a regional based inspector.

to followup on licensee corrective action for the potential degradation of safeguards bus voltage reported in Licensee Event Report (LER) 79-26. The inspection involved 5 inspector-hours on site by one NRC regional based inspector.

Results:

No items of noncompliance were identified.

1843 246 Region I Form 12 (Rev. April 77)

8 0 01310 OU i

s DETAILS 1.

Persons Contacted

• H. Autio, Plant Superintendent T. Danek, Operations Supervisor P. Laird, Maintenance Supervisor J. Staub, Technical Assistant to the Plant Superintendent

,,

The inspector also interviewed several plant operators.

• Denotes those present at the exit interview.

2.

Possible Safeguards Bus Voltage Dearadation a.

A recent computer study performed by the licensee disclosed that if offsite voltage is degraded to its minimum expected value (95%

of 115 KV), with the site electrical distribution system in its startup configuration (4 Main Coolant Pumps operating with the center 2400 V bus fed from offsite power), that voltage at the safeguards buses would be less than required if safeguards loads started on a safety injection.

The licensee's proposed temporary corrective action is to station an extra operator in the Control Room during startup (until the center E400 V bus is supplied by the main turbine generator)

whose sole function is to trip the bus tie breakers isolating the center 2400 V and 480 V buses from offsite and to verify that automatic isolation of the center 480 V Emergency Bus from the 480 V bus occurs upon receipt of a Safety Injection Actuation Signal (SIAS).

b.

The inspector reviewed the following plant procedures to verify that the requirements for stationing the dedicated operator and a description of his duties had been incorporated.

OP 2100, Plant Startup from Cold Shutdown, Rev. 20 OP 3003, Emergency Plant Load Reduction or Shutdown with or without Cooldown, Rev. 3 OP 3000, Emergency Shutdown from Power Rev.11 Special Order 396 1843 247

.

.

Except as noted below, no inadequacies were identified.

(1) OP-3000 should be changed to require stationing the dedicated operator prior to energizing the center 2400 V bus from offsite and restarting the Main Coolant Pumps fed from this bus.

(2)

For plant trips that involve automatic isolation and re-energization of the No. 1 2400 V bus, designate one of the regular reactor operators to isolate the.No. 1 2400 V bus if a SIAS is encountered.

The licensee acknowledged the above findings and agreed to incorporate these coments into the necessary procedures.

This item is unresolved pending review of the revised procedures.

(29/79-14-01)

c.

The inspector interviewed the dedicated operator in the Control Room and verified that he was familiar with his required duties.

The inspector expressed a concern that the operator could err in selecting the breakers to be tripped at the time of a SIAS.

The licensee agreed to plainly mark the affected circuit breakers with a clearly visible paint on the breaker control switches.

This will be reviewed in a subsequent inspection.

(29/79-14-02)

d.

Permanent corrective action discussed with the licensee in a meeting with representatives of NRR Division of Operating Reactors, involves procurement and installation of voltage regulators (automatic tap changers) on the low voltage side of the No. 2 and 3 Station Service Transformers.

The licensee has committed to complete installation of these transformers by November 30, 1979.

Performance of this modification will be reviewed in a subsequent inspection.

(29/79-14-03)

3.

Unresolved Items An unresolved item is an item for which more information is required to determine if the item is acceptable, an item of noncompliance, or a deviation.

Detail 2 contains unresolved itens.

4.

Exit Interview The inspector met with a licensee representative at the conclusion of the inspection to discuss the scope and findings of the inspection as detailed in this report.

1843 248 3