ML20215N550

Forwards Response to Resident Inspector 861029 Concerns Re Condition of Turbine Bldg & safety-related Equipment Contained Within,Per Util Identification of Potential Problem in Event of Steam Line Break

ML20215N550
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	10/31/1986
From:	Withers B PORTLAND GENERAL ELECTRIC CO.
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
Shared Package
ML20213F933	List: ML20213F931 ML20215N550
References
TAC-64233, NUDOCS 8611060319
Download: ML20215N550 (5)

Text

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Bart D Waners Vce Presdent October 31, 1986 Trojan Nuclear Plant Docket 50-344 License NPF-1 Mr. John B. Martin Regional Administrator, Region V U.S. Nuclear Regulatory Commission 1415 Maria Lane, Suite 210 Walnut Creek CA 94596-5368

Dear Sir:

TROJAN NUCLEAR PLANT Response to Resident Inspector's Questions of October 29, 1986 Attached is our response to questions by the NRC Resident Inspector of October 29, 1986 regarding the Turbine Building at the Trojan Nuclear Plant.

The potential for a problem in the unlikely event of a steam line break was initially identified by engineers at Portland General Electric Company.

The condition of the Turbine Building and safety-related equipment contained therein poses no threat to public health and safety. The interim modifications were a precautionary measure pending further analysis of low i

probability steam and feedwater line breaks.

We would be pleased to provide any additional information that you may desire in regard to this response.

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l Sincerely, n.w-~ m, _

Bart D. Withers l

Vice President Nuclear I

I Attachment c: Mr. Lynn Frank, Director State of Oregon Department of Energy i Mr. S. A. Varga Director, PWR-A Project Directorate No. 3 k h LY y 3 e a. w , 2, e c y m c4 3W j

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Response to Resident Inspector's October 29, 1986 Page 1 TROJAN NUCLEAR PLANT RESPONSE TO RESIDENT INSPECTOR'S OUESTIONS OF OCTOBER 29, 1986

1. What safety-related equipment, including lines and monitoring equipment, is in the Turbine Building?

Response

See attached list.

2. Which of the above equipment is in separate rooms, and how is it protected from cold weather?

Response

The attached list denotes which safety-related equipment in the Turbine Building is in separate rooms. These rooms have separate heating, ventilation, and air conditioning (HVAC) systems that protect the equipment within them from cold weather.

3. Which of the above equipment is not in separate rooms, and how is it protected from cold weather?

Response

The attached list denotes which safety-related equipment in the Turbine Building is not in separate rooms. Equipment in the general areas of the Turbine Building is protected as follows:

a. As an initial measure following siding removal, plastic sheathing has been placed to protect equipment that could potentially be affected by inclement weather. Local thermometers have been placed to monitor temperatures, and temporary procedures are in place to provide local heating, if required. The areas where siding has been removed are toured and inspected at scheduled intervals by plant operating personnel,

b. As a second interim measure, heavy-duty plastic tarps will provide weather protection where the siding has been removed.

The scheduled tours and temporary procedures will be maintained.

At all times, conditions will be maintained within acceptable equipment design parameters.

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Response to Resident Inspector's October 29, 1986 Page 2

4. What specific safety standards or procedural guides were used for designing and erecting the scaffolding system now in place in the Turbine Building?

Response

Trojan Plant Modifications Procedure PMP-9, " Seismic Category II/I Scaffolding", governs the construction of scaffolding in areas where safety-related equipment might be impacted. This procedure contains guidelines for span lengths, column heights, bracing, and lateral restraints to ensure the scaffolding can safely withstand an earthquake.

Although not directly over or in close proximity to safety-related -

equipment, the scaffolding provided in the Turbine Building for local weather protection was built in accordance with PMP-9, and is structurally adequate to resist design basis seismic events.

5. What earthquake standards apply to the structure of the Turbine Building?

Response

The Turbine Building has been dynamically analyzed, and it has been concluded that the structure will withstand the safe shutdown earthquake (Ref. FSAR Section 3.8.4.1.4). In addition, the enclosures for safety-related equipment within the Turbine Building have been designed and built to withstand design basis seismic events.

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, 6. Has there ever been an instance of safety-related equipment at the Trojan Plant experiencing freezing due to cold weather? What equipment experienced the freezing? Was any of it in the Turbine Building?

Response

Steam pressure transmitter sensing lines in the Main Steam Support Structure (between the Containment and Turbine Buildings) have frozen due to severe cold weather on several past occasions. There has been no adverse effect on plant operation or safety. No safety-related equipment in the Turbine Building has experienced

! freezing.

I

g 4 Response to Resident Inspector's October 29, 1986 Page 3

7. What was the concern that motivated PCE to open holes in the side of the Turbine Building?

Response

As reported by PGE to the Nuclear Regulatory Commission on October 22, 1986, Trojan has temporarily modified the ventilation for the Turbine Building. These changes involve opening portions of two sides of the building.

This step is an interim measure while permanent modifications are completed to the ventilation systems for several rooms that contain safety equipment in the Turbine Building. The ventilation for these rooms will be isolated from the Turbine Building atmosphere. This is required in the event a break should occur in one of the four large steam lines to the turbine generator.

All of the modifications stem from an analysis begun earlier this year with data supplied by Westinghouse Electric Corporation on the effects of a hypothetical break in one of the steam lines. The data pertains to the temperature and pressure that would occur in the Turbine Building.

8. How long had the Trojan Plant been in operation prior to action being taken on this concern?

Response

Trojan has been in operation since 1976. The ventilation concern became apparent this month.

9. Is the opening of these holes sufficient to guarantee that safety-related equipment will not be affected by steam, heat, or moisture in the event of a high-energy line break?

Response

Yes. The increased ventilation available by siding removal has been included in computer models which have found the environment (steam, heat, moisture) within the Turbine Building would be acceptable for equipment needed to mitigate the offects of a hypothetical high-energy line break.

DRS/mr 0888P

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SAFETY-RELATED EQUIPMENT IN TURBINE BUILDING Equipment Location Turbine Enclosed Room Auxiliary Feedwater Pump Diesel Enclosed Room Auxiliary Feedwater Pump Diesel Auxiliary Open Area Feedwater Pump Room Exhaust Fan

'A' Emergency Enclosed Room Diesel Generator

'B' Emergency Enclosed Room Diesel Generator

'A' Train Enclosed Room Switchaear HP Turbine Impulse Open Area Chamber Pressure Detectors (2)

Cables Various Open and Enclosed Areas Remote Shutdown Enclosed Room Panel Main Steam Line Open Area Pressure Detectors (2 detectors per steam line)

Main Feed Control and Bypass Valves (2 solenoids / Open Area valve = 16 total)

Turbine Auxiliary Enclosed Room Feedwater Pump Room Exhaust Fan DRS/dk 1239W