ML18030B216
| ML18030B216 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry, Sequoyah, 05000000 |
| Issue date: | 03/17/1986 |
| From: | Hornstra D, Mashburn J, Stevens W TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML082340290 | List: |
| References | |
| 0604U, 604U, I-85-992-SQN, NUDOCS 8604070376 | |
| Download: ML18030B216 (32) | |
Text
TENNESSEE VALLEY AUTHORITY NUCLEAR SAFETY REVIEW STAFF NSRS REPORT NO. I-85-992-SQN EMPLOYEE CONCERN:
XX-85-122-030 FINAL REPORT
SUBJECT:
CONTROL OF AC AND DC ELECTRICAL LOADS DATES OF INVESTIGATION:
JANUARY 21-MARCH 31, '1986 INVESTIGATOR:
J.
MASHBURN bATE REVIEWED'Y:
(5~.
HORNSTRA OAT APPROVED BY:
M.
HARRISON
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BACKGROUND The Nuclear Safety Review Staff (NSRS) conducted an investigation to determine the validity of an employee concern that came anonymously by letter to the Quality Technology Company (QTC)/Employee Response
'Team (ERT).
The concern was given by QTC in the following statement:
Sequoyah:
Inadequate management,
This involves inadequate control of or preparation of calculations for loads, and inadequate management and control of load margins, including electrical loads and mechanical loads (heat, BHP, etc.) that translate into electrical loads.
CI has no further information.
Anonymous concern via letter.
I II.
SCOPE A.
The concern statement defined the scope of the NSRS investigation.
B.
The investigation began with an examination of the requirements in 10CFR50 and the commitments in the FSAR for control of electrical loads, calculations, and margins. It included a search of the records for the past five years on the TROI system (a comprehensive computer data base) for NSRS, QA, or NRC reports on this subject.
Interviews were conducted with responsible PGE (Nuclear) design engineers and managers to determine their awareness of problems and the status of work in this area.
Current and past procedures, design criteria, engineering reports, nonconforming condition
- reports, and significant condition reports were examined.
- Finally, the preliminary results of the Design Basis Task Force chaired by Charles Bowman and the Sargent and Lundy (SSL) project for electrical calculation program assessment were reviewed, and TVA employees once assigned to the Clinch River Breeder Reactor (CRBR) were asked to contrast the TVA electrical design program to the program specially developed for CRBR.
The Design Basis Task Force and SRL reports provide some specific action items for which the Nuclear Engineering Division is responsible.
Those specific action items are not included in the scope of this report's recommendations.
III.
SUMMARY
OF FINDINGS A.
FSAR Commitment Lackin The SQN FSAR is very weak in the area of electrical design criteria and standards.
The listing of criteria (section 8.1.5) is preceded by this disclaimer:
"It is IVA's belief that the design meets the intent of these standards and guides."
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The listing, of criteria includes some absolutely required items such as 10CFR50 Appendices A and B.
There is no list of standards for which full compliance is claimed.
The standard to which an SAR should be, compared is defined by NUREG-0800, "Standard Review Plan" (formerly 75/087).
Relevant paragraphs from chapter 8, section 8.1, are as follow.
III.
Review Procedures The PSB reviews Section 8.1 of the SAR to be sure the following items are included:
... the design bases, criteria, standards, regulatory
- guides, and technical positions that will be implemented in the design of the electric power systems, including a discussion describing, the extent to which these criteria and guidelines are followed and a positive statement with regard to conformance of the design to each.
.III.3.
PSB will confirm that the criteria and guidelines identified as being applicable to 'the design of electric power systems include those listed in Table 8-1.
The SAR should include a discussion regarding the applicability of the criteria and guidelines listed and a statement to the effect that the will be implemented (CP) or are implemented (OL) in the design of electrical power systems.
B.
Desi n Im lementation and Control 1.
Re uirements for Desi n Control 10CFR50 Appendix B Criterion III, "Design Control," requires measures to be established for assuring incorporation of regulatory.requirements and design bases into specifications,
- drawings, procedures, and instructions.
This includes incorporation of'uality standards and controlling deviations from the standards, as well as identifying design interfaces and coordinating participating design organizations.
Design changes must be controlled commensurate with measures used to perform the original design.
10CFR50 Appendix B Criterion V, "Instructions, Procedures, and Drawings," requires that activities affecting quality be prescribed by documented instructions, procedures, or drawings.
It requires they include acceptance criteria for determining
,that important activities have been satisfactorily accomplished.
Regulatory Guide (RG) 1.64 endorses ANSI N45.2.11, and TVA has committed to conform to it in the NIZAM, Part IV, Section 2.
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qu ts for the Design of Nuclear xgn Analyses," calls for ntation of assumptions and sumptions that must be verified as the 3.2, "Review of Changes,"
requires her than the original designer is to l have access to pertinent background ated competence in the specific design an adequate understanding of the the original design.
"k of Desi n Control ws undertaken by EEB core sections, worked for years producing detailed closed oversights and omissions that ring and hardwar e fixes (for example, requirements were not properly n process of cable sizing").
A and Lundy is showing a large number of done or records not kept.
EEB
.tified causes of these problems to scriptive procedures and thorough lculations, maintaining configuration aintaining margins, identifying and ac gineering groups, and updating e are activities currently tablxshment of a Nuclear Procedures clem.
This is a commitment in Section
>rate Nuclear Performance Plan dated
- margin in Electrical Design Standard relevant to the stated concern:
fences the results of
- performance is the lack load information at the
- s are set.
Experience has il load information is il capacity is added for
.liminary design figures anticipate this load power supply systems is advised by
.t to the capacity for margin.
As the ure t of actual load equipment and irements, etc.,
the 25 se
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Clearly, the process of converting the preliminary design to the ultimate, as-constructed design while maintaining a proper set of calculations is a challenge to the design organization's ability in configuration management, coordination, and thoroughness in every aspect of its activity.
4.
Desi n Basis Has Not Been Documented The SRL review has shown serious deficiencies in the documented design basis for BFN,
- SQN, and MBN plants.
For example, an excerpt from the February 25, 1986 preliminary results meeting notes reads as follows.
a.
Auxiliar Power Virtually no calculations that are retrievable exist to document the design basis for the following:
o Unit station service transformers sizing.
o Common station service transformers sizing.
o Nonsegrated phase bus duct sizing.
o 6.9-kV switchgear sizing.
o Diesel generators sizing.
o 6900 480-volt transformers sizing.
o 480-volt switchgear sizing.
o 480-volt motor control centers.
o Heat generation by electrical equipment for HVAC system sizing.
All calculations that may have been prepared in these areas were informal and are not retrievable.
- However, none of the above calculations are required for restart.
TVA Standard Design Specifications currently exist which cover the sizing of power cables.
However, it cannot be determined if these documents were actually used as a basis for the Sequoyah design or if the Sequoyah design conforms to them.
Additionally, calculations for special, large cables (e.g., diesel generator feed, main switchgear feeds) that are not covered by standards are required for restart.
These calculations are not available.
System loading calculations have been prepared as a basis for performing the safety-related system voltage calculations.
The data in these loading calculations,
- however, have not been presented in terms of amperes and used to substantiate the current-carrying capability of the transformers, distribution equipment, or cables.
This substantiation, in some form, for safety-related equipment is required for restart.
It should also be noted that loading calculations for nonsafety-related 480-volt buses are not available.
- However, these calculations are not required for restart.
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Virtually no calculations that are retrievable exist to document the voltages and short circuit currents expected at nonsafety-related 480-volt buses and equipment.
All calculations 'that may have been prepared in this area are either out of date or informal and not retrievable.
- However, these calculations are not required for restart.
No calculations that are retrievable exist to address bus transfer time.
All calculations that may have been prepared in this area are informal and not retrievable..
Slow bus transfer does not affect safety-related equipment.
Therefore these calculations are not required for restart.
However, fast bus transfer does affect safety-related equipment and is required for restart.
b.
Control Power Virtually no calculations that are current,and retrievable exist to document the d'esign basis for the following:
- o. Battery, battery charger, and dc distribution equipment
,sizing..
o Alternating current (ac) power supply and'istribution equipment sizing.
o Voltage, loading, short circuit and protective device selection, and coordination for the nonsafety-related control power system.
All calculations that may have been prepared in these areas were informal and are not retrievable.
- However, none of the
.above calculations are required for restart.
No formal calculations exist to document loading on the ac and dc control power systems.
These calculations or other documentation are required for restart.
No calculations exist to document the voltage profile of the safety-related batteries during discharge, their ability to supply loads, or the recharge time of the safety-related batteries.
c.
In the Area of Cable Deratin (1)
Results of manufacturer's tests to determine cable ampacity derating factors due to fire stops and fire coatings were apparently transmitted to project designers for their use.
However, documentation was not available to provide evidence that'his information was factored into the design.
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(2)
The effect of cable tray covers on cable ampacity was judged to be negligible.
- However, no calculations are available to support or document this judgment.
(3)
The effects of increased cable tray fillon cable ampacity is handled on an exception basis.
- However, no documentation was available Eor review.
Cable derating calculations are required for restart.
The tested Eire withstand rating oE cable penetration fire stops is influenced by the cross sectional area of cables
- passing, through them.
Calculations (or other controls) "are required to ensure that the tested configurations envelope designed and installed conEigurations.
No calculations were available in this area.
These calculations are required for restart.
No calculations were available to document and control cable tray loading.
These calculations are necessary to control and ensure that (1) cable weight loads in trays do not exceed those for which the cable tray system was structurally designed and (2) cable depth of filldoes not exceed that on which the cable ampacities were based.
These calculations are necessary for restart.
The Division of Nuclear Engineering has concurred in these assessments and is making plans to deal with them.
One remaining obstacle for the Division of Nuclear Engineering in correcting design deficiencies at SQN is that budgetary approval for such needed engineering work has not always been given by higher management.
Due to the current program improvements in the TVA nuclear program, NSRS assumes this will not be a limitation in the future.
5.
Mana ement and Control of Load Mar ins and Interfaces As described in section III.B.3, the electrical system calculated data base has not been kept up, including keeping track of margins (excess capacity) throughout the systems.
This is illustrated by the statement in the SSL report, "No formal calculations exist to document loading on the AC and DC control power systems."
Additionally, both S&L and the CRBR engineers were aware that the major loads on the electrical system are large motors, typically driving pumps.
Such loads are characterized by motor performance curves and pump performance
- curves, so the actual electrical load is an indirect result of the hydraulic and thermal condition at a point in one of the plant's fluid systems.
Thus, electrical design is downstream of and dependent on mechanical design.
As noted in section III.B.2, interfaces between groups, especially discipline groups, present a
challenge to the Division of Nuclear Engineering's organizational structure.
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SSL electrical engineers were accustomed to accounting for the mechanical (actual) demands on the electrical system and made the following recommendations which were deemed outside the scope of their and EEB's work:
Additional Calculations Re uired to Su ort Plant Desi n Basis a
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Large Motor Sizing Evidence should be in place prior to restart to ensure that Class 1E motors have been appropriately sized to drive the connected equipment.
Conditions to be evaluated include maximum connected equipment driving requirements, normal and reduced voltage conditions, starting and continuous duty operation.
Evidence could be in the form of calculations, vendor-supplied information, test results, or previous operating experience.
In case of the latter two of these items, successful operation under worst case conditions should have been demonstrated.
b.
Alternating Current Motor Operated Valves Evidence should be in place prior to restart to ensure that Class 1E ac motor-operated valves have been appropriately sized to successfully function when required to do so.
Conditions to be evaluated include operating time, normal and reduced voltage, starting and running, and torque and limit switch settings.
Evidence could be in the form of calculations, vendor-supplied information, test results, or previous operating experience.
In the case of the latter two of these items, successful operation under worst-case conditions should have been demonstrated.
(A similar statement was made for dc motor-operated
- valves, but, SQN does not have any.)
A recent problem illustrative of the poor interdisciplinary information flow is ECN L5842.
A venturi (mechanical element) was changed in ECN L5842, affecting the electrical load of the auxiliary feedwater pump,.but affected electrical calculations were not updated because an electrical
~drawin was not identified for change during ECN development.
Based upon these
- examples, the Division of Nuclear Engineering has not included sufficient mechanical calculations in their electrical load studies to have control of the actual margins, even though't is recognized in the industry that this is necessary.
A discussion of margins of all types is given in the draft report of the Design Basis Task Force, showing the relationship of the various types and what should be captured in a Design Basis Document.
The list includes design margins, safety margin (numerical), operating margin, and safety margin with allowance for instrument errors.
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6.
Confi uration Information S stem Inade uate The following examples of inadequate configuration information were noted during this investigation.
a.
A notable result of the equipment qualification project (EQP) was the discovery that the diesel generator calculations were based on the solid-state exciter design because TVA had bought the solid-state equipment for an
- upgrade, but had never installed it.
This miscommunication as to the configuration meant the plant was operated without calculations for the actual diesel generator
- system, and the calculations on file were for. a system not installed.
The information is still not under control however.
because it has since been discovered that a nonconforming condition exists in the supplied solid-state cabinets for WBN and the fifth diesel at SQN; but no one remembered that the warehoused exciters at SQN were the same, and so they were overlooked until NSRS questioned their status during, an investigation.
b.
SQN DCR 1505 was implemented in 1983 to prevent load shedding of the Hotwell pumps upon unit trip, leaving loads on the system that were designed to be removed'or this condition.
Site management implemented the change, invalidating the electrical analysis; and it was three years before EEB core staff happened to become aware of the change and reacted.
The general weakness in configuration control is becoming, recognized.
The Manager of Nuclear Power listed. this as a key problem in his update to the NRC on TVA's problems-March 11,,
1986.
The Design Basis Task Force recognized the value of strict documentation controls in their draft report:
"Although not part of the design basis of the nuclear facility, all detailed engineering drawings and documents 'derived from the design basis as well as 'as-constructed'nd/or
'as-tested'ystem and physical drawings arid documents are
~re uired to establish the base line of the facility."
IV.
CONCLUSIONS AND RECOMMENDATIONS The concern was substantiated.
There has been inadequate management,
- control, and status 'listing of ac and dc electrical loads.
Mhile this investigation was limited to SQN, findings in section III about the Division of'uclear Engineering are generic to all TVA plants.
The investigation showed TVA to be in a period of growing self-awareness involving these issues.
The conclusions and recommendations presented here are not contradictory to some of the reports recently and imminently being produced by the Division of Nuclear Engineering and its contractors.
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I-85-992-SQN-01, Weak FSAR Commitments in Electrical Area Conclusion There are no positive commitments to regulatory guides or industry standards in the SQN FSAR electrical section (section 8).
In fact, even the required regulations and standards are not clearly listed as commitments in section 8.
Words like "belief" and "intent of" do not convey commitment.
The extent to which the Regulatory Guides are met is unclear.
Recommendation Develop a statement of commitments for section 8 that describes the extent to which the listed Regulatory Guides are met.
Review other SQN FSAR sections for similar needs to 'clarify the extent of commitment.
This should become part of the planned annual update activity.
[P-3]
I-85-992-SQN-02, Mar ins Not Controlled and Mana ed Ade uatel Conclusion There is a consensus among reviewers (Design Basis Task Force,
- SGL, and this investigator) that the Division of Nuclear Engineering has never adequately focused on management of margins. It is an important subject worthy of a special program, across discipline lines, to establish the margins for the design basis of the nuclear plants. It cannot be adequately done within each discipline because of the interactions, such as pump horsepower requirements on the electrical system.
Recommendation Establish a program, perhaps by a task force or committee from all disciplines within the Division of Nuclear Engineering, to follow the suggestions on margins of the Design Basis Task Force and those S&L recommendations discussed in section III.5 and develop a formal system for control of margins.
[P-3]
1-85-992-SQN-03, Confi uration Information S stem Inade uate Examples given in section III.B.6 indicate that an effective system for maintaining correct and current information on the disposition of purchased equipment, design
- changes, and the status of planned modification work would reduce the instances of errors leading to SCRs.
Such information must be provided systematically to vendors doing analyses as well as to engineering and modifications groups to achieve the end of reducing errors of omission or oversight about the actual status or disposition.
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Recommendation As part of the current procedures-improvement
- program, address the method for providing status of ECN implementation, disposition of SCRs, and location of purchased equipment to engineering, modification, and vendor organizations whose work may be affected.
If a single procedure or a clearly related set of procedures is not desired, a response to NSRS explaining the alternative chosen would be necessary to.close this item.
[P2]
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DOCUMENTS REVIEWED IN INVESTIGATION I-85-992-SQN AND REFERENCES 1.
Audit deviation report D51-A-84-0006-D01, July 2, 1984, "Inadequate System to Ensure Calculations are Updated to Support Design Changes Made After Plant Operation" (OQA 840801 503) 2.
Clinch River Breeder Reactor Plant Specification 3067-12-21, "Diesel Generators, Class 1E," October 1981 3.
TVA Electrical Design Standard DG-E2.2.2 dated Decembex 1,
1982 4.
OE Procedure OEP-07, "Calculations," April 26', 1985, RO 5.
EEB-EP 22.25, "Auxiliary Power Load Information System Development, Review, Verification, Maintenance, and Use," July 1,, 1985 (B42 850702 502) 6.
SWP EP-43.13,
".Cable Schedule Handling Procedure," April 1, 1982, R5 7.
SCR SQNEEB8532,
".Voltage at Equipment Terminals Inadequate" (B43 860130 916) 8.
SCR SQNEEB8619, unchecked, data was provided for vendor-supplied.
safety-related'alculations, February 12, 1986, (B43 860227 939) l 9.
SCR SQNEEB8605, Rl, deficiencies found by APS section design review (B43 860220 909) 10.
SCR SQNEEB8607, "Deficiencies Found by APS Section Review," January 22, 1986 (B43 860230 929) 11'.
Sargent and Lundy Pxoject Plan for Nuclear Plant Electrical Calculation Pxogram Assessment for Sequoyah, Watts Bar, and Browns Ferry, January 31, 1986, Rl 12.
Sargent and Lundy Meeting Notes Project No. 7517-01, dated February 25, 1986 13.. SQ-'DCR-1505, Hotwell Pump Trip Circuits, September 21, 1983 (L58 840812 607) 14.
Letter from R. Gridley to NRC-NRR, B. Youngblood, dated February 27, 1986, transmitting the "Electx'ical Calculations Program for Sequoyah Nuclear Plant" 'L44 860227 804) 15.
10CFR50 Appendix B, "Quality Assurance Criteria for Nuclear Power Plants and Fuel Reprocessing Plants" 16., NRC Regulatory Guide RG 1.64,, "Quality Assurance Requirements for the Design of Nuclear Power Plants"
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17.
ANSI N45.2.11, 1974, "Quality Requirements for the Design of Nuclear Power Plants 18.
NUREG-0800, "Standard Review Plan" (formerly NlJREG 75/087),
1981 19.
Memorandum, S. A. Mhite to Those listed, "Nuclear Procedures Staff,"
dated March 18,. 1986 (A02 860317 007) 20.
Letter from S. A. Mhite to NRC dated March 10, 1986, transmitting, the revised TVA Corporate Nuclear Performance Plan 21.
Nuclear Quality Assurance Manual (NQAM) dated December 31, 1984 (L16 841213 948) 12
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~ Tvnm: Tas o.cs> (or tIP-ssT UNITED STATES GOVERNMENT Memo rand um TENNESSEE VALLEYAUTHORITY 0
TO: James P. Darling, Site Director,,Bellefonte Nuclear Plant FROM: K. W. Whitt, Director of Nuclear Safety Review Staff, E3A8 C-K DATE
SUBJECT:
NUCLEAR SAFETY REVIEW STAFF INVESTIGATION REPORT TRANSMITTAL Transmitted herein is NSRS Report No.
I-85-439-BLN Subject
'oncernNo.
HUMAN FACTORS CONTROL ROOM DESIGN REVIEW XX-85-122-021 The attached report contains one Priority 3 [P3] recommendation which requires you to take some form of investigative or corrective action within the next four months (July 1, 1986).
No formal response is required for this report unless you disagree with the proposed action.
Please notify us if actions taken have been completed sooner.
Should you have any questions, please contact W. D. Stevens at telephone 6231-K Recommend Reportability Determination:
Yes No X
544U WDS:JTH Attachment cc (Attachment):
H. L. Abercrom e,
SQN W. C. Bibb, BFN W. 'T. Cottle, WBN R. P. Denise, LP6N40A-C G. B. Kirk, SQN D.
R. Nichols, E10A14 C-K QTC/ERT, Watts Bar Nuclear Plant Eric Sliger, LP6N48A-C J.
H. Sullivan, SQN
" ector, NSRS/Designee WATTS BAR NUCLEAAPLANT SITE CRRC C ICFT S Orrcg I48 0 "'db rm As, s ctsonnc1 cmhdc Fns DS R. 10 AHM F
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ENCLOSURE 1
INVESTIGATION REPORTS PREPARED BY NUCLEAR SAFETY REVIEW STAFF AND NOT REVIEWED BY THE EMPLOYEE CONCERN TASK GROUP (ECTG)
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- p
<f P
. r NSRS REPORT NUMBER:
0
~"e e tr'A feei (OS 5-65) (QP-'LVP-5.8e)
UNITED STATES GOVERNAIIENT Memorandum f
TENNESSEE VALLEYAUTHORITY William C Drotleff, Manager of Engineering, W12A12C-E/ee' FROM
- K.
W.
itt, Director of Nuclear Safety Review Staff, E3A8 C-K DATE: A 7 1986
SUBJECT:
NUCLEAR SAFETY REVIEW STAFF INVESTIGATION REPORT TRANSMITTAL hut f.E'ArtPVA)
,-,e OtetgrtCP r ngft-r-Transmitted herein is NSRS 'Report No.
I-85-992-S N (Final Report)
Subject Concern No.
CONTROL OF AC AND DC ELECTRICAL LOADS XX-85->>2-and associated prioritized recommendations for your i%09'9b action/disposition.
f"et Alee Ment Atrg C
Se
.Q Priority 2 [P2] recommendation by Ma 7
1986 fe fe'tee~
e" Sg ee e
It is requested that you respond to this report and the a6t A
eeactee.t tnt
)tice have any questions, please contact M. A. Harrison at e
Recommend Reportability Determination:
Yes X
No 0624U MAH:JTH Attachment cc (Attachment):
H. L. Abercrombie, SQ W.
C. Bibb, BFN J.
P. Darling, BLN R. P. Denise, LP6N40A-C G. B. Kirk, SQN M. L. Martin, IOB-WBN D. R. Nichols, E10A14 C-K E. K. Sliger, LP6N48A-C J.
H. Sullivan, SQN (2)
K. W. Whitt y 25~860409%.05 7 RECEIVED APR 9 lese EMPLOYEE CONCERNS TASK GROUP - WBN
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