ML20237A461
| ML20237A461 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 12/04/1987 |
| From: | Johnston W NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Mroczka E NORTHEAST NUCLEAR ENERGY CO. |
| References | |
| NUDOCS 8712150021 | |
| Download: ML20237A461 (2) | |
See also: IR 05000423/1987015
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DEC 0 I 1987
Docket No.
50-423
Noftheast Nuclear Energy Company
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ATTN: Mr. E. J. Mroczka
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Senior Vice President - Nuclear
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Engineering and Operations Group
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P. O. Box 270
Hartford, Connecticut 06141-0270
Gentlemen *
Subject:
Inspection No. 50-423/87 'S
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This letter acknowledges receipt of your September 1,1987 letter regarding
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NRC Inspection Report 50-423/87-15 and the associated violation and deviation.
Thank you for informing us of the corrective and prevent've actions documented
in your letter. Our August 18, 1987 letter that transmitted Inspection Report.
50-423/87-15 indicated our desire to have a management meeting with you to
discuss (1) the circumstances that 'ved to the apparent deviatic.1 from your FSAR
commitments regarding qualification of masonry walls and (2)That assurances
exist that other similar discrepancies do not exist.
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Based on the information provided in your September 17 letter, we have
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concluded that the apparent deviation was the result of an incorrect assumption
that the design of the battery room masonry walls-was the same as the design of
the control room masonry walls which was in accordance with the FSAR
commitments.
Furthermore, refined calculations have shown.-that:the subject
walls do, in fact, satisfy the FSAR design criteria. Based on the information
you have presented, we have concluded this represents an isolated oversight
and not a more widespread problem. Therefore, a management meeting regarding
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this issue is not necessary.
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Your' cooperation with us is appreciated.
Sincerely,
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William V. Johnston, cting Director
Division of Reactor Safety
8712150021 B71204.
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OFFICIAL RECORD COPY
RL MILL 3 87-15 - 0001.0.0 f'
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12/02/87
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Northeast Nuclear Energy Company
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cc:
W. D. Romberg, Vice President, Nuclear Operations
D. O. Nordquist, Manager of Quality Assurance
R. M. Kacich, Manager, Generation Facilities Licensing
S. E. Scace, Station Superintendent
Public Document Room (PDR)
Local Public Document Room (LPDR)
Nuclear Safety Information Center (NSIC)
NRC Senior Resfdent Inspector
,
State of Connecticut
bec:
Region I Docket Room (with concurrences)
DRP Section Chief
L. Prividy, RI, BV-2
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T. Rebelowski, SRI, Millstone 1&2
B. Doolittle, LPM, NRR
R. Bores, DRSS
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0FFICIAL RECORD COPY
RL MILL 3 87-15 - 0002.0.0
11/29/87
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NORTHEAST UTILITIES
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P.O. BOX 270
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HARTFORD, CONNECTICUT 06141-0270
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(203) 665-sooo
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September 17,1987
Docket No. 50-423
B12680
Re: I&E Inspection
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U. S. Nuclear Regulatory Commission
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Attn: Document Control Desk
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Washington, D. C. 20555
References:
(1)
W. V. Johnston letter to E. 3. Mroczka, Special Inspection
Report 50-423/87-15, dated August 13,1987.
(2)
E.
3.
Mroczka letter to
U.
S.
Nuclear Regulatory
Commission, Masonry Walls - Battery Room of the Control
Building, dated June 22,1987.
(3)
E.
3.
Mroczka letter
to
U.
S.
Nuclear Regulatory
Commission, Masonary Walls - Battery Room of the Control
Building, dated July 23,1987.
Gentlemen:
Milbter<e Nuclear Power Station, Unit No. 3
Response to I&E Inspection No. 50-423/87-15
Pursuant to the provisions of 10CFR2.201, this report is submitted in reply to
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Reference (t), Appendix A and Appendix B which informed Northeast Nuclear
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Energy Company (NNECO) of an apparent Severity Level IV violation and a
deviation. This was the result of items of noncompliance noted during the NRC
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review conducted from June 3 through June 25,1987 in the Region I office, of an
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allegation involving the seismic adequacy of the masonry walls around the
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battery rooms at Millstone Unit No. 3.
A.
Violation
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"10 CFR 50, Appendix B, Criterion 111 requires that design control
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measures provide means for verifying or checking the adequacy of the
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design, such as by the performance of design reviews. Northeast Utilities
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Quality Assurance Program reiterates the above requirement in Section
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3.2.4 of the QA program topical report (NU-QA-1).
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Contrary to the above, inadequate design verification of Calculation No.
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12179-NS(8)-108, for the evaluation and qualification of battery room
walls and elabs to seismic Category I requirements, resulted in the lack of
consideration and documentation of several major structural design
aspects. These included (1) design rationale for the selection of one wall
of significantly smaller area than severa! other walls in the battery rooms
WAN$h f
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U. S. Nuclear Regulatory Commission
B12680/Page 2-
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September 17,1987
as the governing design condition, (2)) evaluation of shear stresses along the
boundary of governing wall (or walls , (3) evaluation of the battery room
slab, for seismic inertia loads in the vertical, north-south and east-west
directions, and (4) evaluation of the slab connections and anchoring
mechanisms to the outer concrete walls as a result of the dead weight and
seismic loads.
This is a Severity Level IV Violation."
Response:
NNECO has reviewed this violation and determined that adequate
consideration to these structural design aspects was given, but these
considerations were not fully documented in the original analysis of
masonry walls in the battery room of Millstone Unit No. 3. The four design
considerations noted have been further reviewed in references (2) and (3),
and have been determined to be conservative analysis assumptions.
A
group of structural engineers utilized by Stone & Webster was specifically
assigned to perform masonry wall analysis and design reviews at Millstone
Unit No. 3, as well as for other power plants. This group of engineers was
extremely qualified and had performed numerous block wall evaluations
prior to evaluating the battery room walls. Although not all the structural
design aspects were fully documented, the preparers of the original
calculation utilized sound engineering judgement. References (2) and (3)
have determined that
these design considerations,
although not
documented, are truly conservative and do not invalidate the original
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evaluation.
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Corrective Actions
As stated in References (2) and (3), we have subsequently re-evaluated all
the desigr. aspects and documented that these considerations have no
impact
on
the original evaluation.
Specifically, Reference (3)
demonstrates that when the conservatism are removed from the original
analysis, the battery room walls have ample margin to meet the criteria
stated in the Standard Review Plan (SRP), Appendix A, of 3.8.4.
At present, any modifications or evaluations of safety related structures
and/or components are performed in accordance with corporate
procedures. These procedures are described in the " Nuclear Engineering
and Operations Policies and Procedures Manual" (NEO). Two procedures
exist which ensure that all design assumptions are properly stated and
verified. These procedures are:
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NE&O 5.05 Design inputs and Design Verification, Rev.
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January 30,1986.
NE&O 5.06 Preparation, Review and Approval of Design Analysis .
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and Calculations, Rev.1, September 30,1986.
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U. S. Nuclear Regulatory Commission
B12680/Page 3
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September 17,1987
Therefore, the implementation of these procedures ensures that all
assumptions, similar to those which were part of the battery room
evaluation, are documented and independently reviewed in all future
calculations.
B.
Deviation
"The Millstone Station Unit 3 Final Safety Analysis Report (FSAR) commits
to comply with the requirements in Appendix A to the Standard Review
Plan (SRP) section 3.8.4 for the evaluation of safety related masonry walls.
The SRP does not permit the use of unreinforced masonry walls in newly
constructed plants.
It also does not permit the increase of allowable
stresses beyond the ACI 531-79 Code limits for the Dead Weight (DW) plus
Operating Basis Earthquake (OBE) design loading conditions. The SRP
permits an increase of 50% in allowable stress for tension parallel to bed
joint, and 30% for tension normal to bed joint and for shear carried by
masonry for the DW plus Safe Shutdown Earthquake (SSE) loading
condition.
Contrary to the above, safety related walls in the battery room were
evaluated in accordance with " Analysis Procedure for Masonry Block
Walls", SDM 80-14, which permitted the increase of allowable stresses
above those specified in the ACI 531-79 Code by 33% for the DW plus OBE
design loading condition and by 67% for the DW plus SSE loading condition.
This is a deviation from an FSAR commitment."
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Response:
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On June 10, 1987, the NRC Region I staff questioned the ability of
masonary walls in the Millstone Unit No. 3 battery room of the control
building to resist the original design loads thereby potentially making
batteries inoperable during these design conditions. Subsequently, NNECO
Based on our
performed a thorough review of the orig)inal calculations.
review, NNECO concluded (Reference (21 that the masonry walls in the
battery room are properly designed to resist all the' original design loads.
However, NNECO noted in Reference (2) that the original design
calculations for the masonry walls in the battery rooms deviated from the
Standard Review Plan (SRP) acceptance criteria in two areas and also
informed the Staff that we failed to identify the deviation from the SRP
acceptance criteria and to provide a justification for the deviation.
Although the Standard Review Plan (SRP) Section 3.8.4, Appendix A does
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not permit the use of unreinforced masonry walls in newly constructed
plants, the SRP Section 3.8.4, Appendix A indicates iin part,. " Plants
applying for operating licenses which have already built unreinforced
masonry walls will be evaluated on a case-by-case basis.'" The Millstone
Unit No. 3 battery room masonry walls were constructed during May 24,
1977 to June 16,1977 which is prior to the issuance of the SRP, Revision 0,
July 1981.
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U. S. Nuclear Regulatory Commission
B12680/Page 4
September 17,1987
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NNECO's response to the NRC question #220.38 regarding masonry walls in
safety related areas
was documented in FSAR Section
3.8.4.2.
Specifically, this Section states in part that the masonry walls, in safety
related areas in the plant, comply with the requirements in Appendix A to;
SRP Section 3.8.4. Personnel involved in responding to the above question
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had concentrated their attention on the design of the control room masonry I $
walls. These walls do meet the requirements of Appendix A to SRP Section
3.8.4. While responding to the NRC question #220.38, it was assumed that
all the masonry walls in safety related areas at Millstone Unit No. 3
comply with the requirements of Appendix A to SRP Section 3.8.4.
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correct that FSAR discrepancy, an FSAR revision (Attachment I in
Reference (2)) was initiated. Subsequently, the original design calculations
were reviewed in detail and conservatism
associated with these
calculations have been removed in a revised evaluation (Attachment I in
Reference (3)). The analysis in Attachment I in Reference (3) has shown
that the battery room walls do in fact comply with the requirements of
Appendix A to SRP Section 3.8.4.
Therefore, we conclude that the
masonry walls in the battery room are properly designed and installed to
meet all applicable design conditions, as well as meeting the acceptance
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criteria of the SRP. Based upon this reevaluation, the proposed FSAR
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change in Reference (2) is no longer required and thus the FSAR should
remain unchanged.
At present, all NNECO personnel are responsible to assure that the
information included in the FSAR contains the latest material developed
and to take necessary action to initiate any required changes in accordance
with the Corporate Procedure. This procedure is described in the " Nuclear
Engineering and Operation Policies and Procedure Manual"(NEO). NNECO
as a licensee is likewise responsible to submit to the NRC periodic updates
(at least annually) containing such changes necessary to reflect information
and analyses developed since the submission of the last update in
accordance with 10CFR$0.71(e). An updated Millstone Unit No. 3 FSAR
will be submitted to the NRC no later than November 25,1987 which is 2
years from the date of the initial license.
This update will reflect
information and analyses developed as of 6 months prior to this submittal
(through May 25, 1987). Therefore this update will minimize the potential
for a similar deviation in the future.
We consider this to be our final report for this violation and deviation. We trust
that the above information satisfactorily responds to your concerns.
Very truly yours,
NORTHEAST NUCLEAR ENERGY COMPANY
D N . E nn
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E. J. Mroczka "
Senior Vice President
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By: C. F. Sears
Vice President
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U. S. Nuclear Regulatory Commission
B126SO/Page5
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September 17,1987
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cc:
W. T. Russell, Region I Administrator
R. L. Ferguson, NRC Project Manager, Millstone Unit No. 3
W. 3. Raymond, Resident Inspector, Millstone Unit No. 3
W. V. Johnston, Acting Director, Division of Reactor Safety, Region I
STATE OF CONNECTICUT
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COUNTY OF HARTFORD
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Then personally appeared before me C. F. Sears, who being duly sworn, did state
that he is Vice President of Northeast Nuclear Energy Company, a Licensee
herein, that he is authorized to execute and file the foregoing information in the
name and on behalf of the Licensees herein and that the statements contained in
said information are true and correct to the best of his knowledge and belief.
A&f4x5
/ hlotary P
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My Commission Expires March 31,1988
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