ML19312C362
| ML19312C362 | |
| Person / Time | |
|---|---|
| Site: | Oconee, Mcguire, McGuire  |
| Issue date: | 07/26/1978 |
| From: | Thompson D NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Parker W DUKE POWER CO. |
| References | |
| NUDOCS 7912130893 | |
| Download: ML19312C362 (2) | |
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- F BEFORE THE 6
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In tne Matter of
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DOCKET NOS. 50-269
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DUKE POWER COMPANY )
50-287 PROPOSED FINDINGS OF FACT AND CONCLUSIONS OF LAW SUBMITTED BY l
THE APPLICANT DUKE POWER COMPANY (IN THE FORM OF A PROPOSED INITIAL DECISION)*
- 1. This proceedinginvolves the license application filed by Dt.ke Power Company (Applicant) with the Atomic Energy Commission (Commis-sion) under Section 104b of the Atomic Energy Act of 1954 (the Act), as i
amended. In its application, as supplemented and amended, the Appli-cant has requested, among other things, authcrity to constmet three closed cycle pressurized water reactors, to be known as Oconee Nuclear Station Units 1, 2 and 3, each to operate initially at 2452 thermal megawatts and to be located on the shore of future Lake Keowee, in Oconee County, South Carolina, about eight miles northeast of the Town of Seneca, South Carolina.
(Partial Summary, pp.1 and 2; Safety Evaluation, pp. I and 3).
2.
The application was reviewed by the Regulatory Staff (Staff) of the Commission which concl;.ded that the Applicant has satisfied all Commission requirements for the issuance of construction permits. (Safety Evaluation, In this document, the transcript is cited as "T.p.
, the Applicant's Partial Summary of Application (T.p. 338 el seq.)
as " Partial Summary", the Staff's safety Evaluation (T.p. 397 g seq.) as " Safety Evaluation", and the Application, as supplemented and amended (T.p. 261 g seq.) as " Application".
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pp. 76-77). The aulication was clso reviewed by ti.e Advisory Committoo l
on Reactor Safeguards which concluded that the Oconee Nuclear Station can be constructed at the proposed site with reasonable assurance that it can i
be operated without undue risk to the health and safety of the public.
(Safety Evaluation, Appendix A).
- 3. On July 24, 1967, the Commission issued a " Notice of Hearing on Application for Provisional Construction Permit" in the captioned matter i
which set out the issues to be considered and initially decided by this Atomic Safety and Licensing Board, appointed by the Commission to conduct the proceeding, as a basis for determining whether provisional construe: ion permits should be issued to the Applicant (32 F.R.10996).
- 4. On August 10, 1967, the State of South Carolina filed a petition to participate in the proceeding pursuant to Section 2.715(c) of the Commis-sion's " Rules of Practice",10 CFR Part 2.
Such participation was allowe; by Order of this Atomic Safety and Licensing Board under date of August 11, 1967. The State of South Carolina did participate in the proceeding by the presentation of unsworn statements by several State officials at the public hearing on August 29, 1967. (T.p.159 Aseq.) All of such statements supported the application of Duke Power Company.
- 5. On July 25, 1967, a group of cities and towns in North Carolina, which term themselves the Piedmont Electric Cities, filed a joint "protes:-
to the construction of the three nuclear units by Duke Power Company. The protest included a request that conditions be attached to any construction permits to provide for the purchase by the Piedmont Electric Cities of an undivided interest in,the proposed nuclear power p1 nts. The iaquests 4.
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gnntained in the protest were denied and the protest dismissed by Order of this Atomic Safety and Licensing Board on August 9,1967.
On August 11, 1967, the same group of cities and towns ',all of whom are wholesale power customers of Duke Power Company), aiong with a non-profit corporation, Piedmont Cities Power Supply, Inc., filed a joint petition to intervene in this proceeding, alleging that the Commission is without jurisdiction to grant the Section 104b construction permits and licenses sought by Duke Power Company for the reason that the proposed 2tilization and production facilities are not experimental in character, and ao not con-stitute any research an development project, but in fact are commercial d
t enterprises that should be licensed, if at all, only pursuant to Section 103 of the Act'. These same parties also filed a motion to dismiss the applica-tion of Duke Power Company on the grounds that the Commissior. does not have jurisdiction te issue the licenses requested by Duke Power Company under Section 104b of the Act. The petition to intervene also alleged that Piedmont Cities Power Supply, Inc. has been organized for the purpose of acquiring an undivided interest in the Ocortee Nuclear Station, Units 1, 2 I
and 3; that it would contract to sell power from the Oconee Nuclear Station to the eleven cities and towns at cost; and that such an arrangement would result in a lower cost of power to these cities and towns than if they pur-chased from Duke Power Company at its present wholesale rates.
This Board, by Order entered on August 28, 1967, granted interven-tion to the eleven cities and towns on the grounds that, as customers of Duke Power Company, they have an economic interest in this proceeding which is a " sufficient intorest" to warrant intervention under Section 189 of the Act.
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Intervention was denied Piedmont Cities Power Supply, Inc. in that it does not have such an interest; it seeks only to acquire an interest.
By separate Order issued August 28, 1967, this Board held that the
' application with respect to Oconee Nuclear Station Units 1 and 2, was properly filed under Section 104b of the Act. The intervenors' motion to dismiss the application respecting these units was therefore denied. The Board felt, however, that it could not make a determinatic. of whether the application with respect to Oconee Nuclear Station, Unit 3, was properly filed under Section 104b until further data were available. A decision on the motion to dismiss the application respecting that unit was accordingly deferred.
Th'e rulings of the Board with respect to the motion to dismiss the ap-plication were referred to the Commission for review in accorJ mee with Section 2.730(f) of the Commission's Rules of Practice. By Memorandum and Order dated September 8,1967, the Commission affirmed the Board's denial of the motion to dismiss the application with respect to Oconee Units 1 and 2 and the Board's deferral of the motion to dismiss the appli-cation with respect to Oconee Unit 3. The Commission believed it appro-priate to reserve a decision on Unit 3 until a review of the Board's initial decision.
On August 29, 1967 the. Staff filed a motion with the Commission moving that the Commission direct this Board to certify the question "%hether the petition to intervene filed by the petitioners herein shou'.d be granted".
On or about September 5,1967 Piedmont Cities Power Supply, Inc. filed a motion with the Commission moving that this Board be ordered to certify to the Commission the matter of the Board's denial of the right of Piedmont i
' Cities Power Supply, Inc. to participate by intervention in this proceeding, e
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and that the Order of this Board be reversed. By Order dated September 15, 1967 the Commission denied both the motion of the Staff and the motion Piedmont Cities Power Supply, Inc. without prejudice to the filing of ap-propriate exceptions.in accordance with 10 CFR Part 2 following the issuance of the Board's initial decision.
- 6. The proceeding is a " contested proceeding" under Section 2.104 of the Commission's Rules of Practice.
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Pursuant to the notice of hearing and in accordance with the re-7.
If quirements of the Act and '.he Commission's Regulations, a pre-hearing con-ference was held by this Board in the Oconee County Courthouse, Walhalla, South C'arolina, on August 15,1967. A public hearing was held by this Board on August 29 - 30 and September 12, 1967, to consider the issues i
l specified for a contested proceeding and to consider the further question i
raised' by the Intervenors as to whether the application with respect to Ocones l
Nuclear Station, Unit.3, was properly filed under Section 104b of the Act.
Evidence was introduced at the hearirg by the Applicant, by the Staff and by the Intervenors. A number of persons made limited appearances.
- 8. The Applicant is an electric utility corporation that is soundly.fi-nanced, and has plentiful resources at its command. Its financial position compares favorably with those of the electric utilities industry as a whole.
(Lovejoy Testimony, p. 5; T. p. 430 g seq.) Its current Dun and Bradstreet credit rating is the highest (Aa A1) and Moody's Investors Service rates the Company's first mortgage bonds (88.4% of the long-term debt) as Aaa and sinking fund debentures (11.6% of the long-term debt) as Aa.
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It plans to finance the cost of construction of the proposed facilities in the
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The same manner as it finances the construction of conventional plants.
estim'ated construction costs for the three Oconee nuclear units, including the initial cost of fuel, will be $341,000,000. Approximately 35 - 40 per-cent will come from internal sources and the balance will be financed from outside sources. (Frazer Testimony, p. 3; T. p. 327). The Oconee Nuclear Station is a part of the overall construction program of Duke Power Company and the financing cannot be segregated. The total construction expenditures The by the Applicant for the next five years are estimated at $820,000,000.
Applicant estimates that the financing required for these expenditures will consist of about $295,000,000 from internal sources (primarily deprecia: ion funds), about $400,000,000 from the sale of bonds, and about $125,000,000 from the sale of Preferred and Common stock. (Frazer Testimony, p. 3; T.
- p. 327).
- 9. The Applicant is responsible for the overall design and construction of the Oconee units. The Bechtel Corporation has been retained to render general consulting services throughout design and construction, and to per-form the design of the reactor buildings. (Lee Testimony, p.10; T.p. 274).
The Babcock & Wilcox Company (B & W) will design, manufacture and deliver to the site the three complete nuclear steam supply systems, fuel, and as-sociated engineered safeguards systems (Lee Testitaony, p. 9; T. p. 273).
Duke Power Company is ; urchasing and constructing the Oconee Nuclear Sta-tion in the same manner ns it handles its conventional units - be they fossil fueled or hydroelectric. Duke Power Company has had extensive experience in the design and construction of large electrical supply systems (Lee Testi-mony, pp. 7 and 9; T. pp. 271 and 273; Safety Evaluation, p. 74).
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- 10. The Oconee Nuclear Station site is on the shore of Lake Keowee, now under construction in Oconee County in the northwestern part of South Carolina. Oconee Station will be a part of the Keowee-Toxaway Project which includes two hydroelectric plants now under construction and future thermal and pumped-storage electric generating developments. The station will have a one-mile exclusion radius and will be in an area remote from population centers. All property within the one-mile exclusion radius is under Duke control, either owned, under option, or covered by an easement granting to Duke the control of access and use when necessary. The site is characterized by sound, hard rock fourdations for structures; freedom from flooding; an abundant supply of cooling water from Lake Keowee; an on-site hydroelectric station capable of supplying emergency power; and favorable conditions of hydrology, geology, seismology and meteorology.
The nearb9 Keowee hydro plant tailrace offers the capability of providing emergency water flow by gravity through the Oconee condensers. (Lee Testimony, pp. 6 and 7; T. p. 270; Safety Evaluation, pp. 3-7).
- 11. The three Oconee Nuclear Units are planned for operation in 1971, l
1972 and 1973. The reactors are similar in concept to others now in opera-tion, under construction, or recently licensed by the Commission. (Par tial Summary, p.1).
It is expected that each reactor will operate initially at core power levels up to 2452 thermal megawatts, and all physics and core and thermal hydraulics information submitted in support of the Application is based on a core design for nominal operation at that level. It is expcted, however, that each unit will be capable of ultimate nominal operation at a core power of 2568 thermal megawatts. The facility systems, engineered 7-m
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safeguards and containment are designed consistent with scfo operation at this higher power level. (Lee Testimony, pp. 3 and 4; T. p. 267).
Before operation at any power level above 2452 Mw(t) is authorized by 4
the Commission, the Commission must perform a safety evaluation to as-sure that the core can be operated safely at the higher power level.
(Safety Evaluation, p.1).
- 12. The reactors will be fueled with slightly enriched uranium dioxide pellets contained in zircaloy tubes. Control of reactivity will be provided by a combination of dissolved neutron absorber and movable control rods. The neutron absorber, boric acid, is dissolved in the re-actor coolant for the purpose of controlling the long-term reactivity of the i
core and cold shutdown. Silver-Indium-Cadmium control rods clad in stainless steel arc employed to control short-term changes in reactivity and to provide fant shutdown. capability. (Lee Testimony, p. 4; T. pp.
267-268; Safety Evaluation, pp. 8 - 9).
- 13. Incore instrumentation, consisting of self-powered neutron de-tectors, will be located at pre-selected locations within the core. (Saf ety Evaluation, p. 9).
This instrumentation will allow confirmation of reactor design parameters by monitoring core performance. The fuel core will be supported within a heavy-walled steel reactor vessel, through which water will be pumped to remove heat generated in the core. This thermal energy will be transferred to two once-through steam gen'erators for each unit.
(Safety Evaluation, p. 9; partial Summ'ary, p.10). The steam produced will be used to drive a conventional turbine-generator outside the containment building (Safety Evaluation, p.10), and will generate initially about 839 mega-l l
Ultimately, it is expected that each unit will have a watts of electricity.
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m net electrical capability of about 874 megawatts. (Lee Testimony, p. 4, T.
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There are numerous systems, components and features incorp-14.
prated into the station to protect the public. (Partial S mmary, p.11, ej The first line of protection against the release of fission products
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e from the reactors is the fuel itself, which has a high capability for retain-In turn, the fuel pellets are ing fission products within its own structure.
encased in metal tubes which are designed to withstand greater temperatures and pressures than those to which they will be subjected and to prevent the However, even if some of the fuel rods should escape of fission products.
fail and permit escape of fission products, they would be contained by the reactor coolant system which consists of closed loops also acting as a bar-(Lee Testimony, pp. 4 and 5; T. pp. 268 and 269).
rier.
The engineered safeguards systems (Partial Summary, p.12 - 14) 15.
are designed to protect against the consequences of failures in the reactar system from very small' breaks'up to the complete double-ended severance Engin-of the largest reactor coolant pipe in the system (36-inch ID pipe).
eered safeguards include systems to prevent the release of fission products from the fuel to the reactor building atmosphere; systems to reduce the pres-sure in the reactor building and thereby reduce leakage of fission products from the building; and systems to collect and filter leakage from the reacor building penetrations following an accident.
Protection is provided by supplying adequate cooling water to the core to prevent excessive overheating of the fuel rods and subsequent release of the contained fission products. This cooling water is provided by three
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engineered safeguards systems. A high prassure injection system supplies low temperature, borated water to the reactor coolant system at any pressure up to full operating pressure. This system, which is normally in operation to supply seal injection and makeup water, will protect the reactor system against small failures. Two pressurized core flooding tanks automatically discharge borated water directly to the reactor vessel if the reactor system pressure falls below 600 psig, and a low pressure infection sy.nem supplies borated water to remove decay heat from the reactor following an accident.
These latter two systems afford protection against the larger reactor coolant The pressure in the reactor building following a loss-of-system failures.
coolant accident is limited by two separate and independent heat removal The One system contains three separate fan and cooler units.
systems.
other system contains redundant spray headers which spray low temperature Each of these borated w'ater into the reactor building atmosphere to cool it.
systems without the other has the heat-removal capability of maintaining the reactor buiMing pressure below its design pressure level. (Partial Summary, pp.12 - 14; Safety Evaluation, pp. 50 - 53, 55).
As still a further containment, the reactor building encloses and 16.
contains the entire reactor coolant system to prevent the release of radio-active fluids and vapors to the environment in the remote event of an acci-In the Oconee Station each of the three reactor coolant systems will dent.
be housed in its own prestressed, post-ter.sioned cencr:tc cent =inment build-ing in the shape of a cylinder. The inside dicmeter of each building is 116 feet and the inside height will be 206 feet. Each containment building will rest on an integral reinforced concrete base slab approximately 8-1/2 feet s _ _..
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t thick. The vertical walls will be approximately 3-3/4 feet thick and the
~ dome approximately 3-1/4 feet thick. Each building will be lined with 1/4 inch welded steel plate to provide vapor tightness. Each reactor building containment is designed to limit radioactivity release in the event of an ac-cident to values well below the guidelines established by the Atomic Energy Commission. (Lee Testimony, pp. 5 and 6; T. p. 269; Safety Evaluation, pp. 37, 64-69; Partial Summary, pp.11-12).
- 17. The nuclear steam supply system for each of the Oconee units is similar in concept to several projects already in operation, under con-struction, or recently licensed by the Atomic Energy Commission. The pre-liminary design is based on the technical data v'..ch have been developed in the nuclear industry and on data developed by B & W which is specifically related to the Oconee design. To complete the final detail design of sc.;e components, additional technical information will be obtained. (Partial Summary, p. 22).
The following are the areas of plant design in which additional tech-nical data will be developed to finalize design details:
A.
Once-through Steam Generator Steady-state conditions and operational transients will be
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investigaged in conjunction with the control system to be used for the once-through steam generator. Vibration tests,
including steam generator response to primary system blow-down, will be investigated and the thermal response to both primary and secondary blowdowns determined.
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Control Rod Drive Unit Test Prototype tests on the control rod drives will be conducted under operating temperature, pressure, flow and water chem-istry to provide information on the operability and reliability of the system.
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In-core Neutron Detectors The self-powered in-core neutron detectors are currently un-der test in the Big Rock Point Nuclear Power Plant.
D.
Thermal and Hydraulic Programs The Applicant has proposed scaled flow distribution tests on the vessel and internals and rod bundle tests to determine local mixing and flow effects. Further experimental and analytical work will be done to determine the limiting heat fluxes at various positions within the fuel bundle.
E.
Emergency Core Cooling The Applicant will include emergency core cooling in the de-velopment program. Specifically (a) the completion of the analysis of the spectrum of break sizes in the loss-of-cool-ant accident, (b) the development of the analytical techniques fordetermining blowdown forces on reactor internals, and (c) demonstration that the injection coolant will cool the core in-cluding consideration of core bypass or formation of a vapor lock.
F. Xenon Oscillations The Applicant plans to further develop analytical techniques to determine whether xenon oscillations can occur. If oscil-lations are possible a system for controlling the oscillations will also have to be developed.
(Safety Evaluation, pp. 72-73)-
18.. By Order issued August 28, 1967 this Board held that the Appli-cation respecting Oconee Nuclear Station Units l'and 2, was properly flied under Section 104b of the Act for the reasons that (a) other pressurized water reactors such as the Indian Point No. 2 reactor, and to a lesser degree the San Onofre, the Ginna and the Connecticut Yankee reactors will provide
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of Oconee Units 1 and 2, but not soon enough to influence major compon-i
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ents and thereby change their developmental character, (b) the performance of Unit 1 can have only limited influence on the initial features of Unit 2, and (c) there are associated with the Oconee reactors specific research and development items characteristic of the cases which have been con-sidered to date by the Commission. A decision as to whether the Applica-tion respecting Unit 3 was properly filed under Section 104b was deferred pending further data being made available on the question of whether the Applicant has proposed the research and development program required by the Act for its Oconee Unit 3.
On the basis of uncontroverted testimony (Lee Testimony, T.p. 306-308) adduced at the public hearing on August 29-30, 1967, it now appears that the research and development program cited in the Safety Analysis and in the Partial Summary of Application is equally applicable to Units 1, 2 and 3.
The conclusions that will be reached as a result of that program f
must be committed to the manufacture of hardware and equipment for Unit 3.
L-Unit I will not have come into service and will not have demonstrated its I
operating economics before Unit 3 is in a very advanced stage of construct-ion. In order for Unit 3 to be available for operation by the hot weather load period'of June,1973, the Applicant has already had to make commit-ments for m=$or equipment for Unit 3, including the nuclear steam supply system and the turbine generator. Neither the operation of other pressurized i
I water reactors' of the type proposed by the Applicant nor the performance of i
Oconee Units 1 and 2 will influence major components of Unit 3 or the.re-search and development program applicable to it.
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The reactors planned for the Oconee Station are larger in capacity by a factor of more than four than the largest pressurized water reactor operational today.
(Long Testimony, T. pp. 411-412).
At11 east until reactors of comparable size have demonstrated by operation their tech-nical feasibility and economic competitiveness with other types of gen-erating facilities, the Oconee reactors must be considered " developmental".
No evidence was adduced at the public hearing which would tend to estab-11sh that any pressurized water reactor of the type and size of the Oconee reactors will demonstrate technical feasibility and economic competitive-ness prior to planned operation of Oconee Nuclear Station, Unit 3.
CONCLUSTONS Upon the basis of the consideration of the entire record in this pro-ceeding, a'nd in the light of the findings and discussions hereinabove set out, this Atomic Safety and Licensing Board decides and finds that:
- 1. In accordance with the provisions of 10 CFR 550.35(a),
a.
The Applicant has described the proposed design of the Oconee Nuclear Station, Units 1, 2 and 3, including, but not limited to, the principal architectural and' engineering cri-teria for the design and has identified the major features or components incorporated therein for the protection of the health and safety of the public; b.
Such further technical or design information as may be required to complete the safety analysis and which can reason-ably be left for later consideration, will be supplied in the final safety analysis reports; \\
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Safety features or components, if any, which require research and development have been described by the Appli-cant and the Applicant has identified, and there will be con-ducted, a research and development program reasonably de-signed to resolve any safety questioils associated with such features or components; and d.
On the basis of the foregoing, there is reasonable assurance that (1) such safety questions will be satisfactorily resolved at or before the latest date stated in the application for completion of construction of the proposed facilities and (ii) taking into consideration the site criteria contained in 10 l
i CFR Part 100, the proposed facilities can be constructed and operated at the proposed location without undue risk to the health and safety of the public.
2.
The Applicant is technically qualified to design and construct the proposed facilities; and
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The Applicant is financially qualified to design and construct the proposed facilities; and 4.
The issuance of a permit for the construction of the facilities will not be inimical to the common defense and security or to the health and safety of the public.'
5.
Oconee Nuclear Station Unit 3, is a " developmental" reactor to the same extent as Units 1 and 2, there being no evidence that the operation of any other reactors willinfluence its characteristics or major components; and the application respecting Unit 3 was properly filed un-der Section 104b of the Act. -
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rw THEREFORE, PURSUANT TO THE ACT AND THE COMMISSION'S REGULATIONS, IT IS ORDERED THAT:
- 1. The motion of the Intervenors to dismiss the application with respect to Oconee Nuclear Station Unit 3 is denied; Subject to review by the Commission upon its own motion or 2.
upon the filing of exceptions in accordance with the " Rules of Practice" 10 CFR Part 2, the Director of Regulation is authorized to issue to Duke Power Company provisional construction permits for Oconee Nuclear Station Units 1, 2 and 3 pursuant to Paragraph 104b of the Act substan-tially in the form of Appendix A to the Notice of Hearing in this proceed-ing, within 10 days from the date of issuance of this decision;
- 3. In accordance with Paragraph 2.764, good cause not having been shown,to the contrary, this initial decision shall be immediately effective.
ATOMIC SAFETY AND LICENSING BOARD Dr. John Henry Buck
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Dr. Hugh Paxton Mr. Samuel W. Jensch Dated this day of October,1967 Da I
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ATL ANT A, CEORGI A 30303 JU! 2 61979 In Reply Refer To:
RII:JPO 50-369, 50-370 50-269, 50-270 50-287 Duke Power Company Attn:
Mr. William O. Parker, Jr.
Vice President, Steam Production P. O. Box 2178 422 South Church Street Charlotte, North Carolina 28242 Gentlemen:
The enclosed Circular 78-16 is forwarded to you for information.
If there are any questions related to your understanding of the suggested actions, please contact this office.
Sincerely,
/
T*
udley mpson
- Deput, irector ENCLOSL*RE:
1.
List of IE Circulars Issued in 1978
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JUL 2 61573 ' '
Duke Power Company I
cc v/en:1:
J. C. Rogers, Project Manager McGuire Nuclear Station P. O. Box 2176 i
Charlotte, borth Carolina 28242 M. D. McIntosh, Plant Manager McGuire Nuclear Station P. O. Box 485 Cornelius, North Carolina 28031 J. E. S=1.th, Station Manager Oconee Nuclear Station P. O. Box 1175 Seneca, South Carolina 29676
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UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTIO5 AND ENFORCEMENT WASHINGTON, D. C.
20555 July 26, 1978 IE Cfreular 76-16 LIMITORQUE VALVE ACTUATORS Description of Circumstances:
At Rancho Seco, a Limitorque Type SMB-2 motor-driven valve actuator in a safety feature system failed to function.
The failure resulted from clutch wear which was due to manual operation of the valve and improper heat treatment of the clutch parts.
Other SMB valve actua-tors at Rancho Seco had been subjected to undue clutch wear but were still operable.
Based on information obtained from the licensee and from Limitorque Corporation, undue wear appears to be limited to Type SMB-0, 1, 2, and 3 valve actuators equipped with 3600 rpm motors.
The type SMB valve actuator is provided with a handwheel so that the valve can be actuated manually in the event that power is unavailable.
To shift from motor drive to handwheel drive, the operator must manually position a clutch so that the motor is disengaged from the drive train and the handwheel is engaged. The clutch latches into this position and cannot be manually repositinned.
The next time that the motor is energized, the latch releases automatically and a spring repositions the clutch so that the motor engages the drive train.
i When the clutch is repositioned, a pair of lugs on the motor-side of the clutch engages a pair of lugs on the valve-side.
At the instant the lugs engage, the lugs on the motor-side are being accelerated to full speed and the lugs on the valve-side are stationary.
Before the motor is energized, the relative position of the lugs is random.
This initial position determines the depth of engagement or bite at the instant the lugs make contact. When a full bite occurs, no damage is caused to the lugs.
When a grazing bite occurs, the edges of the lugs are chipped or upset. After the edges are sufficiently rounded, the clutch will not engage and hold for motor actuation.
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IE Circular No. 78-16 July 26, 1978 LISTING OF IE CIRCULARS ISSUED IN 1978 Circular Subject Dr.te of Issued to No.
Issue 78-10 Control of Sealed 6/14/78 All Medical t
Sources Used in Licensees in Radiation Therapy Categories G and G1 78-11 Recirculation M-G 6/15/78 All Holders of Set Overspeed Stops BWR OLs or cps 78-12 HPCI Turbine Control 6/30/78 All Helders of Valve Lift Rod Bending BWR OLs or cps for plants with HPCI Terry Turbine 78-13 Inoperability of Multiple 7/10/78 All Holders of Service Water Pumps Reactor OLs and cps except for plants located in: AL, AK, CA, FL, GA, IA, MS,
SC 78-14 HPCI Turbine Reversing 7/12/78 All Hciders of BWR Chamber Hold Down Bolting OLs or cps for plants with a HPCI Terry Turbine excepting Deane Arnold and Monticello 78-15 Checkvalves Fail to 7/20/78 All Holders of Close In Vertical Reactor OLs or cps Position Enclosure Page 2 of 2 n
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