NLS8700012, Responds to Violations Noted in Insp Rept 50-298/86-30. Corrective Actions:Surveillance Procedure 6.3.1.3 Being Revised to State Specific Precaution to Measure Any Leakage Locally Before Making Repairs
| ML20207N092 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 01/08/1987 |
| From: | Trevors G NEBRASKA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF ADMINISTRATION (ADM) |
| References | |
| IEB-79-02, IEB-79-2, NLS8700012, NUDOCS 8701130453 | |
| Download: ML20207N092 (5) | |
Text
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10CFR2.201 GENERAL OFFICE Nebraska Public Power District
"" "icss*eS*4'*O*0'** *"
NLS8700012 January 8,1987 Nuclear Regulatory Commission Document Control Desk Washington, DC 20555
Subject:
Nebraska Public Power District Response to IE Inspection Report 50-298/86-30
Reference:
1)
Letter from J.
E.
Gagliardo to J.
M.
Pilant dated December 8,1986, " Docket 50-298/86-30" 3
2)
Letter from J. M. Pilant to W. O. Long dated November 25,1986, " Justification for Interim Operation -
Cooper Nuclear Station" 3)
Letter from J. M. Pilant to K. V.
Seyfrit dated February 5, 1980, "IE Bulletin No. 79-02, Pipe Support Base Plate Designs Using Concrete Expansion Anchor Bolts" Gentlemen:
This letter is written in response to Reference 1 which transmitted Inspection Report No. 50-298/86-30.
Therein it was indicated that one of our activities was in violation of Nuclear Regulatory Commission requirements.
The following is a statement of the violation and our response in accordance with 10CFR2.201:
STATEMENT OF VIOLATION Primary Containment Integrated Leak Rate Test 10CFR Part 50 Appendix J, Section III. A.1.(a) requires that:
"If during a Type A test, including the supplemental test specified in III. A.3.(b),
potentially excessive leakage paths are identified which will interfere with i
satisfactory completion of the test, or which result in the Type A test not l
meeting the acceptance criteria III. A.4.(b) or III. A.S.(b), the Type A test i
shall be terminated and the leakage through such paths shall be measured using local leakage testing methods.
Repairs and/or adjustments to equipment shall be made and a Type A test performed.
The corrective action taken and the change in leakage rate determined from the tests and overall integrated I
leakage determined from the local leak and Type A tests shall be included in the report submitted to the Commission as specified in V.B."
Contrary to the above, it was determined from a review of the Cooper Nuclear Station Summary Technical Report on the second periodic Primary Containment Integrated Leak Rate Test, that valves HPCI-MO-19 and RCIC-37 had been repaired after excessive leakage was identified and that the leakage rate prior 8701130453 870108 PDR ADOCK 05000298 G
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t NLS8700012 i
P ge 2 Jr.nucry 8,1987 to repairing the valves was not measured or documented.
The "as found"
- condition of the containment was, therefore, not able to be defined.
This' is a Severity Level IV violation.
(Supplement II) (298/8630-01)
Reason for Violation The statement of violation is correct.
Although 10CFR50 Appendix J is referenced, a specific statement should have been included in Surveillance l
Procedure 6.3.1.3 to measure leakage from potentially excessive leakage paths and to include the results in the Summary Technical Report.
~ Corrective Steps Taken and Resulto ' Achieved Since the leakage from the valves was not measured, it is impossible to amend the Summary Technical Report.
However, personnel responsible for the Primary Containment Integrated Leak Rate Test have been made aware of the importance of local leakage measurement to reconstruct the "as found" condition.
Corrective Steps Which Will Be Taken to Avoid Further Violations Engineering personnel in charge of Primary Containment Integrated Leak Rate Testing are in the process of revising Surveillance Procedure 6.3.1.3, i
" Primary Containment Integrated Leakage Test".
This revision will clearly i
state a specific precaution to measure any leakage locally before making repairs, and to include the results in the Summary Technical Report.
Date When Full Compliance Will Be Achieved Surveillance Procedure 6.3.1.3,
" Primary Containment Integrated Leakage Text", will be revised and CNS will be in full compliance by February 1987.
Reference 1 also requested the District's response to seven (7) unresolved items that were identified in paragraph 5 of the inspection report.
The majority of the items have already been addressed in NPPD's submittal to the l
Commission to justify Interim Operation until the next refueling outage (Spring 1988), with the Standby Gas Treatment System and Control Room ventilation ductwork in a functional condition (Reference 2).
Modifications will be completed in the 1988 outage to restore full compliance with Class 1 Seismic criteria.
Burns and Roe, the - Architect / Engineer for Cooper Nuclear Station (CNS),
has continued their document search for records relating to the Standby Gas Treatment System and Control Room Ventilation System.
Recent correspondence from Burns and Roe addresses some of the concerns highlighted in Paragraph 4 of the Inspection Report.
j Each unresolved item is addressed in subsequent paragraphs.
Item 298/8630-02 Support Self Weight
'1 The weight of the support structures (hangers) has been addressed in the design / design verification of the hanger supports in the two t
. NLS8700012.
P:ge 3 Jcnuary 8,1987 essential HVAC systems (Standby Gas Treatment and Control Room Ventilation). Ductwork.
The Cygna Energy _ Services "as-built" reconciliation calculations-performed in -1986 includc., the effect of self weight.
Preliminary sample calculations have been submitted to the Commission (NRR, Engineering Branch) for review.
Item 298/8630-03 Tension / Shear Interaction I-NPPD has discussed the formula for checking tension and shear interation 'as quoted in the " State of the Art Report on Steel Embedments," (American Society of Civil Engineers, Nuclear Structures, and Materials Committee-June,1984) with Burns and Roe.
Burns and Roe advised that the case of the elliptical curve had been addressed and accepted in the District's response to IE Bulletin 79-02 (Reference 3).
It is concluded that the curve can be applied to Phillips Redhead anchor bolts.
Item 298/8630-04 Dimensional Errors NPPD commissioned Cygna Energy Services (CES) to perform a walkdown and seismic verification of the Standby Gas Treatment System as a parallel operation to the document investigation.
The urgency of the task and the rapid response demanded by NPPD resulted in the realization of the necessity to ensure adequate check points to identify errors caused by the rapid pace of work.
As such three separate l
checks on documentation were performed:
1.
The "as-build" upon which the seismic verification and subsequent design modifications were based.
2.
Before the "For Construction" drawings of the proposed modifications were approved and passed to the construction crews, an additional check was carried out and if necessary the design calculation modified.
3.
On completion of the modifications, the system (hangers and ductwork) was "as-built" and a full as-build reconciliation calculation performed.
The calculations performed by CES in 1986 from the as-build reconciliation have been completed.
Sample calculations of the ductwork analysis and supports have been sent to the Commission (NRR, Engineering Branch) for review.
1 Item 298/8630 Welding Procedures NPPD has not been able to locate all the welding records associated with the Control Room Ventilation and Standby Gas Treatment Systems.
It is not evident from a review of the Contract E70-19, Section G, which welding code was utilized in the construction and installation of ductwork and duct supports.
The material and installation was in some instances v
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~Janutry 8, 1987-procured and installed to Air Moving & Conditioning Associates Codes (AMCA).
Discussions with the original A/E (Burns & Roe Company) have continued with regard to this topic.
It is considered that the supporting structures were welded in accordance with AWS Codes using prequalified procedures.
As such, individual weld records would not necessarily be held by NPPD.
The ductwork, including ductwork supporting structures, were installed in accordance with the Standard Heating and Ventilation Codes using the Ductwork Manual for Sheet Metal and Air Conditioning and Ventilation Systems per the Sheet Metal and 4
Air Conditioning and Ventilation National Association (SMACVNA)
Standards.
In the uncertainty of the criteria associated with welding codes, CES was instructed to perform weld capacity checks on welds in the system. To this end, minimum weld size calculations based upon AWS, AISC and visual surveys were performed using a thickness of 1/16 inch and the lowest allowable stresses for base metals.
Where transition welds are evident, the lowest base metal allowable stress has been used.
The preliminary results of these bounding case weld capacities were utilized in the reconciled "as-built" calculations for the Standby Gas Treatment System and in the preliminary calculations of the Control Room Ventilation System.
These. calculations have been submitted to the NRR (Engineering Branch) for review.
Item 298/8630-06 Control Room Calculations Further investigations by the A/E (Burns and Roe) have identified additional calculations which include the following items:
a.
Anchor bolts were evaluated for both tension and shear.
The interaction formula was not explicitly applied in the vendor calculation since the factors of safety were in excess of the original contract specification requirements.
A recent check of the original results indicated the requirements of the interaction formula were met.
b.
Combined stress checks were performed in the Waldinger design.
The method used was in accordance with the applicable AISC requirements during the time of construction.
c.
Class I Seismic Supports were designed by equivalent static 4
approach, using specified "g"
values.
With this approach, individual hanger frequencies are not required.
Weld capacities and as-built drawings are addressed in NPPD's response to unresolved Items 298/8630-07 and 298/8630-05.
Burns and Roe is preparing a list of documentation which will be used by NPPD to supplement NPPD construction records.
In addition to pursuing the above course of action, NPPD directed CES to perform a seismic verification, and if deemed necessary, produce i
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' P:g2 5 Janu ry 8,1987 modifications to rectify deficiencies associated with the support structures of essential ductwork.
Preliminary calculations have been completed by CES and have been forwarded for review by NRR, Engineering Branch.
Item 298/8630-07 Control Room Walkdown CES has completed a walkdown of the essential sections of the Control Room Ventilation System ductwork.
The drawings are in production and will be reviewed by NPPD in due course.
A preliminary check of the field sketches has been completed.
Findings from this walkdown were addressed in Reference 2.
Item 298/8630-08 Class II Seismic Design The CNS USAR Revision 4, dated 07/22/86, Volume V,Section XII, Subsection 2.3.5.1.2 states:
" Class II Structures and Equipment were designed to resist effects of seismic loads with the horizontal base shear coefficient as determined from the Uniform Building Code, Zone 1 or taken as 0.1g, which ever is greater.
The base shear is then to be distributed and structures designed in accordance with the provisions of the Uniform Building Code, with 1/3 allowable increase in basic stress."
Other subsections in USAR Vol. V,Section XII, address seismic design, notably 2.3.5.1 and 2.3.5.2.
The design and verification associated in the rectification of the deficiencies in the Standby Gas Treatment System and the Control Room Ventilation System ductwork hangers will be pursued throughout 1987 and will be completed during the 1988 Spring Outage.
The Standby Gas Treatment System (suction side) modifications are complete and the final as-built reconciliation will be reviewed by NPPD in due course.
Nebraska Public Power District will continue to address any outstanding concerns related to these unresolved items.
If you have any further questions, please contact me.
Sincerely, y O' H G. A. Trevors Division Manager of Nuclear Support GAT /gsm/grh:cb18/4(2A) cc:
J. E. Gagliardo, Chief Reactor Projects Branch NRC Region IV NRC Senior Resident Inspector Cooper Nuclear Station