ML20235G651

Forwards Info & Figures from Facility & NRC Training Documents,Per 870706 Telcon Request for Sketches or Drawings of Core Barrel for Better Identification of Alleged Crack Described in Wf Kane 870527 Ltr

ML20235G651
Person / Time
Site:	Seabrook
Issue date:	07/07/1987
From:	Elsasser T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
To:	Tracy S EMPLOYEE'S LEGAL PROJECT
References
NUDOCS 8707140336
Download: ML20235G651 (18)

Text

l 54

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z. JUL 0 7 W Docket'No. 50-443 Employee's Legal Project ATTN: Ms. Sharon Tracy P. O. Box 633 ,

Amesbury, Massachusetts 01913

Dear Ms. Tracy:

4

Reference:

William F. Kane letter to you dat'ed May 27, 1987 i This refers-to your' telephone discussions with Messrs. William F. Kane and Donald R. Haverkamp of this office on July 6, 1987. During.those conversations, you requested copies of sketches or drawings of the core barrel so that you could better-identify,..the specific location of the alleged crack described in the en-closures to the referenced letter.

As agreed during those telephone. calls, I am enclosing selected descriptive in-formation and figures from Seabrook and NRC training documents. I hope this is responsive to your needs.

Sincerely,

. Original SiM O Thomas C. Elsasser, Chief Reactor Projects Section 3C Division of Reactor Projects

Enclosures:

As Stated cc w/encls:

'Seabrook Hearing Service List R. J. Harrison, President and Chief Executive Officer i Ted. C. Feigenbaum, Vice. President of Engineering and Quality Programs l William B. Derrickson, Senior Vice President 1 Warren J. Hall, Regulatory Services Manager Donald'E. Moody, Station Manager Public Document Room (PDR) local Public Document Room (LPDR)

Nuclear Safety Information Center (NSIC)

NRC Resident Inspector State of New Hampshire I

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8707140336 870707 3 l PDR ADOCK 0500 P

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.__ ._. _ _ _ _ _ _ _ ._______________a

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t Employee's Legal Project 2 JUL 0 71987 bec w/encls:

Region I Docket Room (with concurrences)

Management Assistant, DRMA (w/o encl)

DRP Section Chief Robert J. Bores, DRSS J. Durr, DRS A. Cerne, DRP E. Wenzinger, DRP W. Kane, DRP D. Haverkamp, DRP i

I:DR) RJ- RI:DRS R fP

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H e[kamp/meo Elpa ser Du r .nzinger 7/7/87 7 f 17 7(1 f t 3 0FFICIAL RECORD COPY l ( l

Seabrook 1 Service Hear,1_ng_ List

\,

l Thomas Dignan. Esq E. Tupper Kinger, Esq.

John A. Ritscher, Esq. Assistant Attorrsy General Ropes and Gray Office of Attorney General 225 Franklin Street 208 State House Annex Boston, Massachusetts 02110 Conco-J, New Hampshire 03301 Mr. Bruce Beckley, Project Manager Resident Inspector New Hampshire Yankee Seabrook Nuclear Power Station P.O. Box 330 c/o U.S. Nuclear Regulatory Comm.

Manchester, New Hampshire 03105 P. O. Box 1149 Seabrook, New Hampshire 03874 Dr. Murray Tye, President Mr. John C. DeVincentis, Director Sunn Valley Association Engineering and Licensing 209 Summer Street Yankee Atomic Electric Company Haverhill, Massachusetts 08139 1671 Worcester Road Framingham, Massachusetts 01701 Robert A. Backus, Esq. George D. Bisbee, Esq.

O'Neill, Backus, and Spielman Assistant Attorney General 116 Lowell Street Office of the Attorney General Manchester, New Hampshire- 03105 25 Capitol Street Concord, New Hampshire 03301 l l

Mr. Phillip Ahrens, Esq. William S. Jordan, III Assistant Attorney General Diane Curran Of' ice of the Attorney General Harmon, Weiss, and Jordan State House Station # 6 20001 S. Street, N.W.

Augusta, Maine 04333 Suite 430 Washington, D.C. 20009 Jo Ann Shotwell, Esq. D. Pierre G. . Cameron, Jr. , Esq Office of the Assistant Attorney General Counsel General Public Service Company of i Environmental Protection Division New Hampshire j One Asburton Place P. O. Box 330 j Boston, Massachusetts 02108 Manchester, New Hampshire 03105 Ms. Diana P. Randall Regional Administrator, Region I {

70 Collins Street U.S. Nuclear Regulatory Commission Seabrook, New Hampshire 03874 631 Park Avenue King of Prussia, Pennsylvania 19406 Richard Hampe, Esq. Mr. Alfred V. Sargent New Hampshire Civil Defense Agency Chairman 107 Pleasant Street Board of Selectmen Concord, New Hampshire 03874 Town of Salisbury, MA 01950 j Mr. Calvin A. Canney, City Manager Senator Gordon J. Humphrey l City Hall ATTN: Tom Burack I 126 Daniel Street U.S. Senate i Portsmouth, New Hampshire 03810 Washington, D.C. 20510 l l

l i

Lo*

- -Ms.,Letty.Hett' . Mr. Owen'B. Durgin, Chairman L ..

" Town of Brentwood- Durham Board of Selectmen RFD Dalton Road Town of Durha's.

'Exeter, New Hampshire 03833' 'Durham, New Hampshire 03824 Ms. Roberta C. Pevear. Charles Cross, Esq.

Town of Hampton Falls Shaines, Mardrigan, and McEaschern

Drinkwater. Road 25 Maplewood Avenue Hampton Falls,:New Hampshire 03844 P.-0. Box 366 Portsmouth, New Hampshire 03801' Ms. Anne. Verga Mr. Guy Chichester, Chairman Chairman', Board of Selectmen Rye Nuclear Intervention Committee Town Hall' .

. c/o Rye Town Hall

' South Hampton, New Hampshire 03827 10 Central Road Rye, New Hampshire 03870 Mr. Angie Machiros, Chairman Jane Spector Board of Selectmen Federal Energy Regulatory Comm.

. 'for'the Town of Newbury 825 North Capitol Street, N.E.

25 High Road Room 8105 Newbury, Massachusetts .01950- Washington, D.C. 20426 Ms. Rosemary Cashman, Chairman Mr. R. Sweeney Board of Selectmen New Hampshire Yankee Division Town of Amesbury Public Service Company of Town Hall. New Hampshire Amesbury, Massachusetts 01913 7910 Woodmont Avenue Bethesda, Maryland 20814 Honorable Peter J. Matthews Mr. Donald E. Chick, Town Manager Mayor, City of Newburyport Town of Exeter Office of the Mayor 10 Front Street City Hall . Exeter, New Hampshire 03823 Newburyport, Massachusetts 01950 Mr. Warren J. Hall Mr. William B. Derrickson Public Service Company of Senior Vice President '

New Hampshire- Public Service Company of P. O. Box 300 'l New Hampshire Seabrook, New Hampshire 03874 P.O. Box 700, Route 1 Seabrook, New Hampshire 03874 Administrative Judge Administrative Judge Alan S. Rosenthal, Chairman Bary J. Edles Atomic Safety and Licensing Appeal Atomic Safety and Licensing Appeal Board Board U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission

. Washington, D.C. 20555 Washington, D.C. 20555 Administrative Judge Administrative Judge

'Howard A. Wilber Helen F. Hoyt, Chairman Atomic Safety and Licensing Appeal Atomic Safety and Licensing Appeal Board Board' U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Washington, D.C. 20555

/ _ . _ . . . ____ _ ______ __-_____ _ _ -___ -

,- Administrative Judge Administrative Judge Emmeth A. Lusbke Jerry Harbour Atomic Safety and Licensing Board Atomic Safety and Licens~ng Board U.S. Nuclear Regulatory Commission U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Washington, D.C. 20555 Edwin J. Reis, Esq. H. Joseph Flynn, Esq.

Office of the Executive Legal Assistant General Counsel Director Federal Emergency Management Agency i U.S. Nuclear Regulatory Commission 500 C. Street, S.W.  !

Washington, D.C. 20555 Washington, D.C. 20472 Edward A. Thomas Carol S. Sneider, Esq.

Federal Emergency Management Agency Assistant Attorney General 442 J. W. McCormack (POCH) Office of the Atteraey General Boston, Massachusetts 02109 One Ashburton Place, 19th Floor Boston, Massachusetts 02108 Paul McEachern, Esq. R.ichard A. Haaps, Esq Shaines and McEachern Haaps and McNicholas 25 Maplewook Avenue 35 Pleasant Street Portsmouth, New Hampshire 03801 Concord, New Hampshire 03301 J. P. Nadeau Allen Lampert Board of Selectmen Civil Defense Director 10 Central Street Town of Brentwood Rye, New Hampshire 03870 20 Franklin Street Exeter, New Hampshire 03833 William Armstrong Sandra Gavutis, Chairman Civil Defense Director Board of Selectmen Town of Exeter RFD #1, Box 1154 10 Front Street Kensington, New Hampshire 03827 Exeter, New Hampshire 03833 Anne Goodman, Chairman William S. Lord Board of Selectmen Board of Selectmen 13-15 Newmarket Road Town Hall - Friend Street Durham, New Hampshire 03824 Amesbury, Massachusetts 01913 Michael Santosuoss'o, Chairman Jerard A. Croteau, Constable Board of Selectmen 82 Beach Road South Hampton, New Hampshire 03827 P. O. Box 5501 Salisbury, Massachusetts 01950 Stanley W. Knowles, Chairman Judith H. Mitzner Board of Selectmen Silverglate, Bernter, Baker, Fine, P. O. Box 710 Good, and Mitzner North Hampton, New Hampshire 03862 88 Broad Street Boston, Massachusetts 02110 Norman C. Katner Bary W. Holmes, Esq.

Superintendent of Schools Holmes and Ells School Administrative Unit No. 21 47 Winnacunnet Road Aluani Drive Hampton, New Hampshire 03842 Hampton, New Hampshire 03842 Jane Doughty Seacoast Anti-Pollution League 5 Market Street Portsmouth, New Hampshire 03801

1.0 SYSTEM FUNCTION The function. of the reactor vessel, its internals, and the core is to provide a region where power _ production, via the nuclear chain reaction, may take place.

. The reactor vessel contains the fuel and support assemblies in the smallest package possible. The internals establish the coolant flow path, absorb loads, and align the incore instrumentation assemblies. The core components hold the fuel pellets

-in a critical geometry and in a mechanically stable array so that vibration is minimized and cooling is ensured. Nuclear fission by the fuel provides the energy to sustain the power cycle.

l RVI-1 I 7/86 ,

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2.0 GENERAL SYSTEM DESCRIPTION l

The reactor vessel and its internals are composed of five major assemblies. They are the reactor vessel, the vessel head, the lower internals assembly, the upper internals assembly, and the instrumentation support assembly. (See Figure RVl-2.1.)

The core is composed of physically identical subassemblies called fuel assemblies.

The 193 fuel assemblies that make up the core are supported by the reactor vessel internals. The fuel assemblies are positioned vertically in a precise orientation and are securely held between the upper and lower internals. Positioning is accom-plished with various alignment pins and hold-down springs that will be discussed in detail later in this text.

Neutron absorbing material is used to control the reactivity of the core. This is done by placing neutron absorbing rods into the fuel assemblies from the top and by using soluble baron in the primary coolant. The neutron absming rods, called control rods, can be moved in and out of the core while the reas is in operation.

The control rods are grouped into clusters of 24 rods, called rod cluster control assemblies (RCCAs), which are fastened at the top to a common spider assembly. A drive rod attaches to each of 57 spider assemblies and extends all the way through the upper internals and through a penetration in the vessel head to the control rod drive mechanism (CRDM) housing on top of the reactor vessel. As the control rods are driven into and out of the core, the upper internals support and guide the drive rods and all other RCCAs.

FIGURE RVI-2.1 SIMPLIFIED REACTOR l' t ControI P.M Cluster Fuel Assembly Control Rod gg orive Mechanism Controf Rod J orsve Tube i Reactor

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.i - Closure

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instrumentalsOn luDet '

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Instrumentation in the core measures coolant exit temperature and neutron flux.

This instrumentation consists of fixed thermocouple and two types of neutron detectors (fixed and movable).

-The instrumentation is enclosed inside tubes called flux thimbles, which enter the

' core through penetrations in the bottom of the reactor vessel, j

I RVI-3 7/86

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3.0 DETAILED SYSTEM / COMPONENT DESCRIPTION 3.1 Reactor Vessel and Supports The reactor vessel is a pressure vessel with an integral bottom head, vessel sup-ports for mounting the vessel, a removable upper head called the closure head, and nozzles. The pressure vessel is a vertically mounted, cylindrical vessel with the hemisphericallower head welded to its bottom and the removable, hemispherical upper head bolted to its top. The closure head is removable to allow entry into the vessel for servicing and replacing the internal components.

The vessel is approximately 507 in, high with a 173 in. inside diameter. It is constructed primarily of welded manganese-molybdenum steel plate and forging. The internal surfaces, which are in contact with the primary coolant, are clad with stainless steel or nickel-chromium-iron (NI-Cr-Fe) alloy at least 1/8 in. thick.

Figure RVI-3.1 shows the various thicknesses of material used in the construction of the vessel. The closure head flange and the reactor vessel flange provide the structural rigidity necessary for bolting the head to the vessel.

There are eight coolant nozzles on the reactor vessel; four inlet and four outlet nozzles with inside diameters of 27.5 and 29 in. respectively. The inside diameter of the inlet nozzles diverges from 27.5 in, to 35.2 in. to lower the velocity of the fluid impinging on the reactor internals. The lower fluid velocity decreases both the pressure drop through the reactor and the hydraulic loads on the inter-nals. The nozzles are fabricated from manganese-molybdenum forgings with weld-deposited cladding and are welded to the pressure vessel with their centerlines on a common horizontal plane, as shown in Figure RVI-3.2.

The vessel flange is a ring forging 25 in wide that contains 54 threaded holes for the 7 in. studs that hold the vessel head in place. The studs are threaded into the vessel flange at the bottom. The head is lowered into place over the studs and held by nuts screwed onto the studs over washers. On the outside sur-face of the flange, a seal flange provides a temporary seal between the reactor vessel and the refueling canal liner. The inside surface of the flange has a ledge from which the reactor vessel internals are hung.

Two self-energizing 0-ring gaskets made of polished, silver-plated Ni-Cr-Fe alloy (inconel 718) are installed between the mating surfaces of the closure head flange and the reactor vessel flange. The gaskets prevent leakage of the primary coolant between the vessel and thu closure head. The O-rings energize themselves by per-mitting primary coolant pressure to act on their insides through slots. which causes them to expand. Two grooves are machined into the vessel flange to receive the 0-ring gaskets. The flange 0-rings are each held in place by 16 circumferential clips bolted to the closure head flange, as shown in Figure RVI-3.3.

Two head gasket monitoring connections are furnished with the reactor vessel closure head to detect seal leakage. One detects leakage between the inner and outer 0-ring, while the other detects leakage outside the outer O-ring. Piping and various valves are used to direct any leakage to the reactor coolant drain tank. Excessive leakage will be indicated by a high temperature alarm from a surface-mounted.

resistance temperature detector (TE-401) located on the bottom of a leakoff line.

The alarm occurs at 200*F. A telltale connection indicates very small leaks, which RVI-4 7/86

FIGURE RVI-3.1 .

1 REACTOR VESSEL j

- Control Rod Drwe j Mechanism Adapters I (78 Reqd ) Vent Line i

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O j Stud. Nut and Washer (54 Reqd )

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27 5" 29 0..

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Support l' 10 75"-M 507" k

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7 -- 5 38" instrutnentation Nozzle j $ (58 Reqd i Q .

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RVI-5 7/86 .

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I FIGURE RVI-3.2

. REACTOR VESSEL SUPPORT inies f inlet Ouites

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,5 FIGURE RVI-3.3 REACTOR VESSEL SEAL

_ r Top Head Flange L

Head Flange ,:

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.'X' Section Thru O Ring Chp Assembly AC v 147 i 'i e Ciadding Aeactor Coolant pb __ _' . -

SectlOn A A Drain Tank No V85588 Flange @> View of Chp Recess and O-Ring Seal g

Leakoff Connections - } I' l hp w i s o. . w Recess g I ,

Section Thru Reactor h

Top Head Flange J RVI-6 7/86

might not activate a high temperature alarm. A pneumatically controlled globe valve (RC-V-147) is provided to isolate the system from the reactor coolant drain ta nk. This globe valve fails open if 125 V DC power or control air is lost.

The reactor vessel is supported by steel pads on four of the coolant nozzles.

The pads rest on steel base plates atop a support structure that is attached to the concrete foundation wall, as shown in Figure RVI-3.2. The vessel support pads are 3.5 in. high by 10.25 in. wide.

Thermal expansion and contraction of the vessel are accommodated by sliding sur-faces between the support pads and base plates. Side stops on these plates keep the vessel centered and resist lateral loads, including al; pipe loads. The sup-port shoes and support structure are air cooled by the reactor cavity cooling sys-tem (RCCS). i The exterior of the reactor vessel is insulated by canned, stainless steel, reflec-tive sheets. The insulation is 3 in. thick and contoured to enclose the top, sides. I and bottom of the vessel. All of the insulation is removable, but access to the )

insulation around the sides of the vessel is limited by the surrounding concrete shield.

Both the upper and lower reactor vessel heads contain penetrations which are used ,

for instrumentation or control devices. The penetrations are welded to a head l to prevent coolant leakage (see Figure RVI-3.1). The lower reactor vessel head j has penetrations for 58 incore nuclear instrumentation thimbles. The nozzles for j these penetrations are welded to the vessel and extend 12 in, into it. These noz-  !

zies are joined to the lower internals assembly with a slip fit. Conduits are welded to the nozzles below the reactor vessel and extend to the seal table.

The top of the closure head contains 79 penetrations. All but one consist of 4 in outside diameter (OD) Inconel tubes that are welded to the interior of the closure head. A threaded,316-stainless-steel adapter is welded to the upper end of each tube. CRDM housings are attached to 57 of these adapters. The housings 1 are threaded onto the adaptors and seal welded.

Each of the penetrations used for CROMs employs a thermal sleeve, which is basi-cally a 2.27 in., 304-stainless-steel tube located within the penetration and supported from the top of the adapter. The sleeve is installed to minimize thermal stresses imposeo on the penetration weld on the closure head. As an RCCA is moved, water will be displaced in the CRDM housing. Since coolant temperature differences 1 will exist between the upper head region and the CRDM housing, the sleeve will i prevent the rapid temperature changes from occuring at the penetration weld. I There is an inverted-cone-shaped guide attached to the end of the thermal sleeve.

The thermal sleeve guide directs the RCCA drive shaft assemblies into the thermal sleeve as the closure head is lowered over the internals during assembly.

The remaining 4 in. penetrations were origin 3lly designed to be used for incore thermocouple access points (five) and part-terigth control rod CRDMs. Due to de-sign changes, nei*er are utilized at Seabrook and the penetrations are capped and seal welded. One vt the capped penetrations, however,is used by the reactor vessel level instrumentation system (RVLIS). A 1 in. pipe is connected to the cap, and spool pieces allow for removal when the closure head is removed from the vessel.

RVI-7 7/86 L

The only penetration m the closure head that has not yet been discussed is a 1 in. OD penetration used as a vent path for the vessel. An inconel tube passes through the penetration and is welded to the interior of the head. Again. the tubing is installed with spool pieces to facilitate removal of the closure head.

Three lifting lugs spaced evenly around the head are used to move it. The head also has a support ring, which accepts a head cooling shroud. This shroud directs flow to the CRDMs. When the closure head is being installed, three hr,ad guide studs are inserted into the vessel flange to guide the closure head onto the ves-sel. Fine alignment of the closure head is accomplished by means of four short alignment keys, which are attached to the internals to mate with the keyways in the vessel flange and closure head flange. Once the head is in place, the guide studs are removed. Next, 54 studs are installed with their nuts and washers.

The studs are sequentially elongated by three tensioners working simultaneously.

The nuts are then tightened over the studs to mcintain the tension on the studs after the tensioner has been removed.

3.2 Reactor Internals The reactor internals, in conjunction with the fuel assemblies, are designed to direct reactor coolant through the core to achieve acceptable flow distribution and to restrict bypass flow so that the heat transfer performance requirements are met for all modes of reactor operation. In addition, required cooling for the pressure vessel head will be provided so that the temperature differences ~ be-tween the vessel flange and head do not cause the flange to leak during reactor operation.

3.2.1 Lower Internals Assembly The lower internals assembly (lower core support structure) consists of the core barrel, core baffle and former plates, lower core plate and support column assembly, neutron shield pads (panels) with attached specimen holders, and the lower core support forging (see Figure RVI-3.4). i i

The core barrel supports and contains the fuel assemblies and directs coolant flow.

The core barrel is a cylindrical shell,172 in. in diameter and 400 in. long. It hangs from a ledge in the reactor vessel and is aligned by four flat-sided pins that are press-fit into the barrel at 90' intervals. Four reactor coolant outlet nozzles penetrate the shell in the upper region. The lower end of the core barrel is restrained f.om transverse movement by the radial support system.

The radial support system consists of six equally spaced key and keyway joints around the vessel inner wall (see Figure RVI-3.5). At each point, an inconel clevis block is welded to the vessel. An inconel insert block is bolted to each clevis block, forming the keyway. Six keys are welded to the lower end of the core barrel. These keys engage the keylocks when the core barrel is lowered into the vessel. This design accommodates radial and axial expansion of the core bar-rel, but transverse movement is restricted.

Thirty-two flow nozzles located on the barrel flange direct a portion of the coolant upward to cool the head. The coolant then passes down flow holes in the control I

rod guide tubes and into the main outlet flow stream.

RVI-8 7/86

FIGURE RVI-3.4 LOWER INTERNALS--ELEVATION j l

Head and Vessel Aligning Pin

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Flange /

Upper Core Barrel #

Upper Core Plate

! Guide Pin t O j Neutron Panel f oreC Barrel h

,= yBaffle irradiation '

Specimen Basket N

. Former 4

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Lower Core Plate

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Radial Support ,

5 Key N Support Ring

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' h r3 Support Column Upper Tie Plate 'O-rs-)M

~j Lower Core Butt Type Column / r a Support Plate A Instrumentation Lower Tie Plate Guide Column Of fset instrumentation Column Secondary Core Support l RVI-9 7/86

FIGURE RVI-3.5 KEYWAY JOINT (TYPICAL OF SIX) j Reactor  %,h __ _

Lower Core  !

Vessel- ,N ~

Support Wall Forging x -

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x K Key Key Way N ,

1 There are four neutron shield pati s._ They attenuate fast neutrons that would other-wise excessively irradiate and ambrittle the vessel walls. In addition, gamma radiation is attenuated to alleviate thermal stresses due to uneven gamma heating of the vessel.

The neutron shield pads are 147 in. high, 48 in. wide, and 2.8 in. thick. They are made of 304 stainless steel and are attached to the core barrel adjacent to the fuel assembly corners by means of spacer blocks. This arrangement allows cooling flow between the pads and the vessel.

The reactor vessel specimen holders attach to the outside of the neutron pads. Two of the specimen holders hold two specimen capsules each, and two hold only one specimen capsule each. Samples of material from the reactor vessel have been placed in the holders and will be used to evaluate the effects of radiation on the vessel. Evaluatior of these specimens will help to determine permissable heatup and cooldown rates for the vessel. One sample will be evaluated after the first refueling, and subsequent samples will be checked at 10, 20, and 30 years.

Two samples will be held in standby.

The lower core support forging (see Figures RVI-3.6 and 3.7) is welded to the bottom of the core barrel. The core support forging is 20 in. thick stainless steel and has 96 support columns. There are also 115 coolant flow holes, including a 17 in. hole directly above the secondary support structure. This hole, or manway, .

was provided to allow access for checking alignment during assembly.

RVI-10 l 7/86

FIGURE RVI-3.35 REACTOR CUTAWAY gf j k%I l If . U , !I r I .

ll f i

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Drive Shaft

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Closure Head Top Support l g .b.s ,. Assembly

M Plate , I Control Rod Internals ,l Guide Tube Support Ledge ;3 '. '

t - Rod Cluster Control Core Barrel s'f >

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Outlet Nozzle - r, ji g inlet Nozzle Upper Core Plate-

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