ML19312D804

Responds to IE Bulletin 80-02, Inadequate QA for Nuclear Supplied Equipment. Feedwater Spargers Scheduled to Be Installed During 800301 Outage Were Purchased from Ge. Installation Will Be Performed in Accordance W/Qa Program

ML19312D804
Person / Time
Site:	Cooper
Issue date:	03/17/1980
From:	Pilant J NEBRASKA PUBLIC POWER DISTRICT
To:	Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
References
IEB-80-02, IEB-80-2, NUDOCS 8005050154
Download: ML19312D804 (3)

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Nebraska Public Power Distr.ic t retc~o~e STATE March 17,1980 Mr. K. V. Seyfrit, Director U.S. Nuclear Regulatory Commission Office of Inspection and Enforcement Region IV 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76011

Subject:

Response to IE Bulletin No. 80-02

Dear Mr. Seyfrit:

In response to IE Bulletin 80-02 " Inadequate Quality Assurance for Nuclear Supplied Equipment" the following information is submitted' for your review:

1.a. Have reactor feedwater spargers and thermal sleeves manufactured and/or fabricated by the Marvin Engineering Company been purchased and/or installed in your facility? Since Marvin Engineering is principally a subcontracting Company, determine if your equipment originated with the Marvin Company and was eventually supplied to your facility through another con-tractor / supplier.

Response

The feedwater spargers scheduled to be installed during the March 1,1980, outage were purchased from General Electric who subcontracted the sparger fabrication to Marvin Engineering Company. Although these spargers were procured as non-essential, all fabrication shall be performed in accordance with the General Electric BWR Quality Assurance Program as described in Topical Report NEDO-11209-04A.

! It is currently under investigation by GE/NPPD as to whether or not spargers now installed at CNS were fabricated by Marvin Engineering. In any event, all feedwater spargers now installed will be changed out during the spring 1980 (scheduled for March 1,1980).

1.b. Provide a description of this equipment to include its purchase date and its design function during both normal and accident conditions.

Mr. K. V. Seyfrit March 17,1980 Page 2

Response

(See Enclosure 1 for purchased material description.)

Design Function During Normal Conditions The feedwater spargers are perforated stainless steel heaters located in the mixing plenum above the downcomer annulus. A separate sparger is fitted to each feedwater nozzle and is snaped to conform to the curve of the vessel wall.

Sparger end brackets are attached to vessel brackets to support the weight of the spargers, and wedge blocks position the spargers away from the vessel wall.

Feedwater flow enters the center of the spargers and is discharged radially inward and downward to mix the cooler feedwater with the downcomer flow from the steam separators before it contacts the vessel wall. The feedwater also serves to collapse the steam voids in the mixing plenum and to subcool the water flowing to the jet pumps and recirculation pumps.

Design Function During Accident Conditions During accident conditions, the feedwater spargers are utilized by the high pressure injection system (HPCI).

The primary function of the HPCI system is to provide a coolant makeup to the reactor vessel to keep the reactor core covered and cooled for small system breaks. The secondary function is to depressurize the reactor so that the low pressure coolant injection system or the reactor core spray cooling system in the CSCS network can become effective for somewhat larger breaks than can be handled entirely by HPCI inventory makeup.

Although the feedwater spargers clearly assist in the safety function of the HPCI System as described, their functional loss would not inhibit, in any way, HPCI's ability to flood the core. (Refer to NEDO-10174 -

Consequences of Postulated Flow Blockage Incident in a Boiling Water Reactor.)

2. For each piece of identified equipment, provide the performance history associated with its _'qe. This should include the cause of any failures or mati'inctions and the frequency of such events.

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Mr. K. V. Seyfrit March 17,1980 i Page 3 '

Response

The present feedwater spargers were installed in 1976 and have experienced 17 cycles. NUREG-0312 (Interim Technical Repor't on BWR Feedwater and Control had Drive Return Line Nozzle Cracking) recommends feedwater sparger examination after 20 but prior to 40 cycles. The original spargers were subject to 71 cycles with a very minimal amount of cladding cracking observed. All spargers currently installed at CNS will be removed during the spring 1980 outage. Post-removal inspection for cracking and other failures is not planned.

3. Provide information on the supplier's and receiver's QA/QC program in effect at the time of purchase. This information should be discussed in terms of its providing sufficient basis for judging that the integrity of the equipment is sufficient to permit plant operation during normal and accident conditions.

Response

All work described in Enclosure I shall be performed in accordance with the General Electric BWR Quality Assurance Program as described in Topical Report NEDO-11209-04A .

The feedwater sparger assemblies are "not important to safety" nor subject to the provisions of the ASME Code; however, a Product Quality Certification (PQC) shall be provided by General Electric as the primary quality assurance record.

The stress analysis of the final machined configuration is the only safety-related item. It will be performed to all the provisions of the applicable ASME Code.

Upon receipt at CNS, and before installation, NPPD QA and CNS Engineering will perform a complete review of the sparger fabricaton records package as submitted by GE.

Should you have any questions or comments concerning the above information, please do not hesitate to contact me.

Sincerely, 3M

. Pilant Director of Licensing and Quality Assurance JMP/few:bn17/11