ML20036C092
| ML20036C092 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 06/07/1993 |
| From: | Chrzanowski D COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-93-002, IEB-93-2, NUDOCS 9306140054 | |
| Download: ML20036C092 (3) | |
Text
________ _
. Commonwalth Edison 00' 1400 Opus Place Downers Grove, Illinois 60515 June 7,1993 U.S. Nuclear Regulatory Commission Washington, DC 20555 Attention: Document Control Desk
Subject:
Braidwood Station Response to Bulletin 93-02, " Debris Plugging of Emergency Core Cooling Suction Strainers."
Braidwood Station Units 1 and 2, 1
(NRC Docket Numbers 50-456 and 50-457) i The purpose of this letter is to provide the Braidwood Station response to j
Bulletin 93-02. The details of the Braidwood response are contained in the attachment. In summary, Braidwood Station has performed the requested actions of the Bulletin. Because no fibrous air filters or other temporary sources of fibrous material, not designed to withstand a LOCA, were identified at Braidwood Units 1 and 2, no compensatory measures were required. Bulletin compliance was verified by a combination of visual examinations and review of administrative controls.
In addition, Braidwood will perform a walkdown of Unit 2 containment during the next outage of sufficient duration. Commonwealth Edison will notify the NRC of the results of this inspection.
To the best of my knowledge and belief, the statements contained in this document are true and correct. In some respects these statements are not based on my personal knowledge, but on information furnished by other CECO employees, contractor employees, and/or consultants. Such information has been reviewed in accordance with company practice, and I believe it to be reliable.
If there are any questions or comments, please contact me at (708) 663-7292.
Sincerely,
+
w David k Chrzanowski
'F Nuclear Regulatory Services e
Attachments: Braidwood Station Response to Bulletin 93-02.
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Regional Administrator-RIII o
88 J. Hickman, Project Manager-NRR/PDIII-2 "O
R. Assa, Braidwood Project Manager-NRR/PDIll-2 I
g S. DuPont, Senior Resident Inspector (Braidwood)
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A'ITACHMENT BRAIDWOOD RESPONSE TO BULLETIN 03 02 Braidwood has completed it's evaluation of the subject identified by the bulletin. This evaluation consisted of an engineering review of the materials inside of the containment, a review of administrative controls, and a containment walk-down. This evaluation concluded that Braidwood is adequately protected against the concerns raised in the bulletin.
i REVIEW OF MATERIALS INSIDE CONTAINMENT Braidwood Station has fibrous filter material inside of Containment charcoal filters. They are used only for habitability of personnel when necessary, and they have a charcoal and HEPA filter downstream to remove any fibrous material during ventilation system operation. This stem is designed to be Seismic
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Category 1 and is not required during a LOCA. On 5/29/93, an entry of the Unit-1 Containment was made. During this entry, the Charcoal Filter /Prefilter Housing I
was inspected. The housing was good condition. The dampers appeared to be able l
to be closed when required, and nothing was obstructing the closure.
The Station Radiological Protection Department does, during maintenance outages in Containment, install temporary portable HEPA units, which do contain a prefilter made of a fibrous material. These units are installed in accordance with BwRP 1310-13, titled " Set-Up and Operation of Portable Air Filt ration / Ventilation Equipment." This procedure does specify that when the need for such a unit has terminated, that the unit shall be returned to storage, which, at Braidwood,is on the 346' elevation of the Auxiliary Building. This procedure also has a table which serves as a HEPA unit location log, which has a space that documents that a unit that has been used has been returned to storage.
ADMINISTRATIVE CONTROLS Braidwood Operating Surveillance Procedure 1/2BwOS 5.2.c-1, titled
" Containment Loose Debris Inspection," is performed just prior to establishing containment integrity. This surveillance was performed at the establishment of containment integrity at the completion of the last refuel outage on Unit-1 on 10/23/92. This surveillance verifies that the containment is free ofloose debris.
After containment integrity has been established, those areas entered into or those areas where work was perfbrmed require inspection.
Surveillance procedure BwVs 5.2.d.2-1, titled " Visual Surveillance of Containment Recirculation Sumps," verifies that the suction inlet piping is not obstructed by debris, and that the containment sump components show no evidence ofloss of structural integrity, abnormal corrosion, or missing parts. This surveillance was performed on both Unit-1 and Unit-2 at the completion of the last respective refuel outage.
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ATTACHMENT BRAIDWOOD RESPONSE TO BULLETIN 93-02 CONTAINMENT WALKDOWN In addition to the afbrementioned visualinspection of the Containment ventilation Charcoal Filter /Prefilter housing, the following Inspections on Unit-1 containment were conducted by the site ISI Group on 05/29/93:
The lead shielding storage area, located on the 377' elevation outside missile barrier was inspected. This inspection revealed that the outside door was locked, lead blankets in good condition and stacked orderly against the missile wall (not the cage walls). Lead blankets were the only items stored in the cage, and all lead blankets in containment were stored in the cage.
The door that enters into the inside missile barrier area was inspected, These were visually inspected through the mesh housing around the sumps. No visable materials or debris appeared on the screens. All sections of the screens were in place.
The walkdown identified small portions ofinsulation exposed on the Chilled Water (WO) system piping. The exposed insulation is Armallex II Foam Fire Retardant Plastic which is considered permanent and is non-fibrous material. As a result it is not necessary to remove the insulation or reinstall the lagging prior to unit start up as required by the Bulletin ihr fibrous materials. In addition, the exposed portions of the Armaflex insulation are not deteriorated and are firmly adhered to the piping. However, as a precaution, Station Support Engineering will reconfirm the acceptability of the foam insulation for use on the WO system. NTS action item number 456-101-93-00201 will be assigned to track this resolution.
All other piping and equipment inside containment is lagged with stainless steel, insulated with a non-fibrous material, or is not insulated at all.
No other temporary fibrous materials were found during the remainder of the walkdown, which was approximately three hours in duration and conducted by three site engineering personnel.
SUMMARY
The engineering review, administrative controls, and the walkdowns of the Unit-1 containment have demonstrated that Braidwood is adequately protected against the concerns raised in the Bulletin 93-02. Further, Byron Station, which is largely identical in design, has recently completed a walkdown ofits Unit-2 Containment.
These reviews are adequate to justify delaying a walkdown of Braidwood Unit-2 containment until the next outage of suflicient duration. NTS action item number 457-101-93-00201 will be assigned to track this ; tem.
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