ML20039C025
| ML20039C025 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 12/23/1981 |
| From: | Crutchfield D Office of Nuclear Reactor Regulation |
| To: | Kay J YANKEE ATOMIC ELECTRIC CO. |
| References | |
| TASK-04-02, TASK-4-2, TASK-RR LSO5-81-12-078, LSO5-81-12-78, NUDOCS 8112280330 | |
| Download: ML20039C025 (8) | |
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.u December 23, 1981 Docket tio.50-029
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LS05 12-078 9
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Mr. James A. Kay F
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Senior Engineer - Licensing (G " !1 M Q y //
Yankee Atomic Electric Company 1671 Worcester Road m
Framingham, Massachusetts 01701
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Dear Mr. Kay:
SUBJECT:
SEP TOPIC IV-2, REACTIVITY CONTROL SYSTEMS DRAFT SAFETY EVALUATION - YAtlKEE R0WE NUCLEAR POWER PLANT Enclosed is a copy of ocr iraft safety evaluation of SEP Topic IV-2, Reactivity Control Systems for Yankee Rowe.
This assessment compares your facility, as described in Docket No.50-029, with the criteria currently used by the regulatory staff for licensing new facilities.
Please inform us if your as-built. 4cility differs from the licensing basis assumed in our assessment.
Your response within 30 days of the date you receive this letter is re-quested.
If no response is received within that time, we will assume that you have no coments or corrections. This evaluation should be a basic input to the evaluation of Topic XV-8 and the integrated safety assessment for your facility unless you identify changes needed to reflect the as-built conditions at your facility. This assessment may be revised in the future if your facility design is changed;pr. if HRC criteria re-lating to this sutdect are modified before the integrated assessment is completed.
Sincerely, Dennis M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing
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J December 23, 1981 Docket No.50-029 LS05 12-078 Mr. James A. Kay Senior Engineer - Licensing Yankee Atomic Electric Company 1671 Worcester Road Framingham, Massachusetts 01701
Dear Mr. Kay:
SUBJECT:
SEP TOPIC IV-2, REACTIVITY CONTROL SYSTEMS DRAFT SAFETY EVALUATION - YANKEE R0WE NUCLEAR POWER PLANT Enclosed is a copy of our draft safety evaluation of SEP Topic IV-2, Reactivity Control Systems for Yankee Rowe. This assessment compares your facility, as described in Docket No,50-029, with the criteria currently used by the regulatory staff for licensing new facilities.
Please inform us if your as-built facility differs from the licensing basis assumed in our assessment.
~
Your response within 30 days of the date you receive this letter is re-
- quested, If no response is received within that time, we will assume that you have no comments or corrections.
This evaluation should be a basic input to the evalua. tion of Topic XV-8 and the int grated safety assessment for your facility unless you identify changes needed to reflect the as-built conditions at your facility.
This assessment may be revised in the future if your facility design is changed.or, if NRC criteria re-lating to this subject are modified before tha integrated assessment is completed.
Sincerely, Dennis M. Crutchfield, Chief Operating Reactors Branch No. 5 Division of Licensing l
Enclosure:
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Mr. James A. Kay cc Mr. James E. Tribble, President Yankee Atomic Electric Company 25 Research Drive Westborough, Massachusetts 01581 Greenfield Community College 1 College Drive Greenfield, Massachusetts 01301 Chairman Board of Selectmen Town of Rowe Rowe, Massachusetts 01367 Energy Facilities Siting Council 14th Floor One Ashburton Place
' Boston, Massachusetts 02108 U. S. Environmental Protection Agency Region I Office ATTN: Regional Radiation Representative JFK Federal Building Boston, Massachusetts 02203 Resident Inspector Yankee Rowe fluclear Power Station c/o U.S. NRC Post Office Box 28 Monroe Bridge, Massachusetts 01350 t
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SAFETY EVALUATION REPORT SEP TOPIC IV-2r REACTIVITY CONTROL SYSTEMS INCLUDING FUNCTIONAL DESIGN AND PROTECTION AGAINST SINGLE FAILURES YANKEE ROWE NUCLEAR POWER PLANT DOCKET No.50-029 I..
INTRODUCTION The purpose of this evaluation is to insure that the design basis for the Yankee Rowe reactivity control systems is con-sistent with analyses performed to verify that the protection system meets General Design Criterion 25.
General Design criterion 25 requires that the reactor protection system be designed to assure that specified acceptable fuel design limits are not exceeded for any single malfunction of the reactivity control systemse such as accidental withdrawal of control rods.
Reactivity control systems need not be single failure proof.
Howevere the protection system must be capable of assuring that acceptable fuel design limits are not exceeded in the l
event.of a single failure in the reactivity control systems.
The review criter.ione covered in this evaluations is address-l ed in Section II.
Review areas that are not coverede but are i
related and essential to the completion of.this topic are cover-l l
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ed by other SEP topics addressed in Section III.
The scope of the SEP topics is defined in the " Report on.the Systematic Evaluation of Operating Facilities" dated November 25/ 1977.
This report is limited to the ident i fication of inadvertent con-trol rod withdrawals and malpositioning of. controls rods which may occur as a result of single failures in the control rod drive system.
II.
REVIEW CRITERION The review criterion for this topic is based upon Section 7.7, Part II of the NRC Standard Review Plan.
In the specific' case of the reactivity control systems a single failure shalL not cause plant conditions more severe than those for which the reactor protection system is designed.
III.
RELATED SAFETY TOPICS The fotLowing listed review areas are not covered in this reports but are related and essential to the compt'etion of this topic.
These review areas are covered by other SEP topics as indicated below.
1.
Analyses of the consequences of. control ~ rod withdrawals'and
the malpositioning_of control rods which may occur as a result of single failures in the electrical circuits of the reactivity control systems are covered by SEP Topic XV-8e " Cont rol Rod Misoperati on (System Malfunction or Operator Error").
2.
Analyses of reactivity insertions occurring as a result of inadvertent boron Jilutions are covered in,SEP Topic XV-10s
" Chemical and Volume Cor. trol System Malfunction that Re-sults in a Decrease in Boron Concentration in the Reactor Coolant."
IV.
REVIEW GUIDELINES The purpose of this evaluation is to identify' inadvertent con-trol rod withdrawals and malpositioning of control rods which may occur as a result of single failure in the control rod drive system for the Yankee Rowe Nuclear Power Plant.
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V.
EVALUATION Information was provided 'in Yankee Atomic Electric Company letter dat ed S ept embe r 17,1981, describing cingle failures within the i
control rod drive system which can cause control rod withdrawals and malpositioning of control rods at the Yankee Rowe Nuclear Power Plant.
Also included was a description of design features
which limit reactivity insertion rates and rod malposition-ings resulting from single failures.
Based upon an audit review of the information provided by the Licensee we con-clude that the folLowing may occur as a result of single failures:
1.
A single rod may drop into the core.
2.
A single rod may not move when movement is commanded.
3.
A single rod may be inadvertently moved or malpositioned.
4.
An entire group may drop into the core.
5.
An entire group may not move when movement is commanded.
This includes both automatic in (based on-T,y,1 and manual commands.
6.
An entire group may be inadvertently moved or malpositioned.
l This includes the simultaneous movement of two groups when only one group is commanded and the inward movement of a group when the outward movement is selected.
7.
AlL rods may drop i'nto the core.
i 8.
AlL rods may not move in when movement commanded.
This i
l includes any number.of groups failing to move in when aLL l
rods are commanded to c;uve.
9.
AlL rods may be inadvertently moved in or malpositioned.
l 10.
An entire group of rods may be withdrawn beyond the 485 MWT.
Limit.
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l The conclusion is based upon the design of the control rod drive system.
The analysis performed by the Licensee found many of the results and the remaining items were noted during the audit.
VI.
CONCLUSION The licensee should revise the evaluation of SEP Topic XV-8 to include the ten items above or should show why these types of failures cannot occur at Yankee Rowe.
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