ML20045B132
| ML20045B132 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 06/10/1993 |
| From: | Withers B WOLF CREEK NUCLEAR OPERATING CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| IEB-93-002, IEB-93-2, WM-93-0079, WM-93-79, NUDOCS 9306160326 | |
| Download: ML20045B132 (4) | |
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i Wt9LF CREEK 1
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NUCLEAR OPERATING CORPORATION l,
Bart D. Withers President and
'I chie, tu,cuwe omcer.
June.10, 1993 l
WM 93-0079 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station F1-137
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Washington, D. C. 20555
Reference:
Letter dated May 11, 1993, 'NFC Bulletin 93-02: Debris Plugging of Emergency Core Cooling Suction Strainers'
Subject:
Docket No. 50-482: Response to NRC Bulletin 93-02 g
i Gentlemen:
This letter transmits Wolf Creek Nuclear Operating Corporation's. (WCNOC) response to the Reference.
The Reference required licensees to' submit ' a' l
written response within 30 days, stating whether the actions requested.by the-Reference have been or will be performed; Specifically, the. Reference requested licensees to identify fibrous air filters or other temporary sources of fibrous material, not designed to withstand a loss of coolant accident' (LOCA), which are installed or stored in containment.
Immediate compensatory measures were required to be-taken to ensure the functional capability of the emergency core cooling system and any such fibrous material was required'to be l
removed from containment prior to restart if the facility was shutdown..
-l In response to the concerns raised in the Reference, a walkdown of containment-was performed on May 11, 1993, excluding the area inside the biological shield (fibrous material applications are not used within the biological shield),
r prior to startup from the sixth refueling outage.
The -only application of fibrous filter material utilized in containment is in the containment atmospheric control filter absorber units.
These units use a moderate type i
prefilter installed in a rigid type metal frame and meet.the design-requirements of ANSI /ASME N509-1976, Section 5.3.
In accordance with design requirements, the material in these filters is moisture ' resistant ~ and is
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designed to withstand the radiation levels and environmental conditions
-l prevalent during a postulated LOCA.
Although the filter-inlet opening is not' i
enclosed, the integrity of the filter material and rigid casing would preclude-any significant fibrous material migration.
Fibrous material (fiberglass piping insulation) is used to insulate essential j
service water lines to the containment coolers.- This material is encased in sheet metal which prevents insulation damage and precludes migration of the material.
There were several instances where fiberglass insulation had been i
removed for testing / inspection activities;
- however, the insulation was reinstalled prior to startup from the sixth refueling outage.
Also, it was j
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9306160326 930610 6 Box 411 ! Burhngton, KS 66839 i Phone: (316) 364-8831
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PDR ADOCK 05000482 an ena.i oppor,un,ty Empiover u1:HCVET j
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- VM 93-0079 Page 2 of 3
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- observed' that insulation blankets had been removed from several valves for:
l testing / inspection activities, but the insulation blankets, including u sheet -
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metal covers, were reinstalled prior to startup.
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No other sources (either temporary or permanent) of fibrous material were identified in containment.
Therefore, based on the results of the walkdown.
i and the information provided above, no further actions.or compensatory measures are required.
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ADDITIONAL INFORMATION Section - 6.2.2.1.2.2 of WCNOC's Updated Safety Analysis Report provides L a.
detailed description of the containment recirculation sumps.
The sumps are.
located as far as feasible from the reactor coolant system piping and components which could become sources of debris.
Thermal insulation used inside containment will not be a significant source of debris.
The insulation utilized in containment has been evaluated to ensure that it will not be subject to degradation under a design basis accident (ULA) or, if in a few dispersed locations the insulation should degrade under DBA conditions, the debris generated as a result of the degradation is trapped by the building components so that the debris will not adversely affect the performance of the 5
sumps. A baffle arrangement consisting of grating, coarse screening, and fine screening completely surrounds the sumps to prevent floating debris-and high '
density particles from entering the sumps.
Based on the discussion above, debris generated as a result of a LOCA will either be retained in an area such as the reactor cavity or refueling pool or must follow a difficult path to reach the recircalation sump screens.
Therefore, no appreciable debris will i
reach the recirralation sump screens to.cause any significant blockage.
- l Technical Specification 4.5.2.d.2 requires, in part, a visual inspection of-
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the two cop;ainment sumps at least once per 18 months.
This visual inspection i
is required to verify that the subsystem suction inlets are n'ot restricted by i
debris and that the sumps' components (trash racks, screens, etc.) show no evidence of structural distress or abnormal corrosion.
This Technical i
Specification Surveillance Requirement is satisfied by - the performance of surveillance test procedure STS EJ-002, " Containment Sump Inspection. "
The results of past performances of procedure STS EJ-002 have not indicated any signs of debris in the containment sumps.
l Technical Specification 4.5.2.c.1 and 4.5.2.c.2 requires, in part, a visual inspection of containment to verify that no loose debris (rags, trash, clothing, etc.) is present in containment which could be transported to the containment sumps and cause restrictions of the-Emergency Core Cooling System j
pump suctions during LOCA conditions for all accessible areas of containment j
prior to establishing containment-integrity (Mode 4, Hot Shutdown) and of the-l areas affected within containment at the completion of each containment ~ entry I
when containment integrity is established.
These Technical Specification 2
Surveillance Requirements are satisfied by the performance of surveillance' l
test procedure STS EJ-001
" Containment inspection."
Administrative procedure ADM 01-110
" Housekeeping Control,"
provides guidelines and defines the responsibilities for housekeeping control in order
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to comply with the applicable regulations regarding housekeeping requirements for the control of work activities, conditions, and environments at Wolf Creek Generating Station. Also, the information contained in NRC Information Notice i
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4 kV 93-0079 Page 3 of 3 92-85, " Potential Failures of Emergency Core Cooling Systems Caused by Foreign Material Blockage," has been incorporated into General Employee Training Lesson Plan GT1245000, which is required to be administered to all plant personnel.
The administrative controls described above provide further assurance that debris migration into the containment sumps will be prevented.
If you have any questions concerning this matter, please contact me at (316) 364-8831, extension 4000, or Mr. Kevin J. Moles at extension 4565.
Very truly yours, Bart D. Withers President and Chief Executive Officer BDW/jra cc:
W. D. Johnson (NRC)
J. L. Milhoan (NRC)
G. A. Pick (NRC)
W. D. Reckley (NRC)
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e STATE OF KANSAS
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) SS COUNTY OF COFFEY
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Bart D. Withers, of lawful age, being first duly sworn upon oath says that he is President and Chief Executive Officer of Wolf Creek Nuclear Operating Corporation; that he has read the foregoing document and knows the content thereof; that he has executed that same for and on behalf of said Corporation with full power and authority to do so; and that the facts therein stated are true and correct to the best of his knowledge, information and belief.
By Ba(t D. Withers President and Chief Executive Officer 1
SUBSCRIBED and sworn to before me this
/O day of
- , 1993.
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