ML17037B671

Letter Regarding Information Concerning a Request Made During a 10/28/1976 Telephone Conversation Relating to the Plant Unique Analysis Report for Torus Support System and Attached Piping

ML17037B671
Person / Time
Site:	Nine Mile Point
Issue date:	11/03/1976
From:	Schneider R Niagara Mohawk Power Corp
To:	Lear G Office of Nuclear Reactor Regulation
References
Download: ML17037B671 (20)

Text

U.S. NUCLEAR REGULATORV ISSION DOCKET NUMBE R NRC FORM 195 50-220

{2-7BI FILE NUMBER NRC DISTRIBUTION FoR PART 50 DOCKET MATERIAL FROM:NIAGARA MOHAWK POWER CORP. DATE OF DOCUMENT TOI G. LEAR SYRACUSE, N.Y. 11-3-76 R.R. SCHNEIDER DATE RECEIVED 11-9-76 QNOTORIZED PROP INPUT FORM NUMBER OF COPIES RECEIVED QLETTER El OR IG INAL SUNCLASSIFIED QCOPV DESCRIPTION ENCLOSURE LTR. RE. TELEPHONE CONVERSATION ON 10-28-76... DDITIONAL INFORMATION CONCERNING THE PLANT UNIQ TRANS THE FOLLOWING...... ALYSIS REPORT FOR TORUS SUPPORT SYSTEM ...W/

TTACHED PIPING.......

1 SIGNED CY. RECEIVED) 9 PAGES)

DONOX REMOVZ PLANT NAME: NINE MILE PT. f/ 1 C~>O33g,g~G SAFETY FOR ACTION/INFORMATION

%SSX -"IED AD ASSI+NgD BRANCH CHIEF: LEAR AD'RO PROJECT MANAGER:

LIC ~ ASST.: PARRISH IN TE R N AL D I ST Rl BUTION F SYSTEMS SAFETY SITE NRC PDR HEINEMAN ENV RO NAI I & E SCHROEDER BENAROYA EN OELD GOSSICK & STAFF ENGINEERING IPPOLXTO MXPC MACCARRY K RKW 0 CASE KNIGIIT HANAUER SIHWEXL OPERATIN REACTO PAWLXCKI PRO ECT MANA EMEN REACTOR SAFE'IIY OPERA N BOYD ROSS EISENII P COLLINS NOVAK SHAD HOUSTON ROSZTOCZY BAER PETERSON CIIECK BUTLER MELTZ RII IES HEI.TEMES AT&I SKOVHOLT SAT.TZMAN WILLIN RUTI3ERG EXTERNAL DISTRIBUTION 'NTIIOLNUMBER LPDR:~E NAT IAB: Bf(OOKIIA ~FN TIC RL'G, VIE ULRX~KHoM OBNL

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NIAGARA MOHAWK POWER CORPORATION NIAGARA I MOHAWK 300 ERIE 80UI.EVARD WEST SYRACUSE, N.Y. IS202 November 3, l976

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Director of Nuclear Reactor Regulation Attn: Mr. George Lear, Chief Operating Reactors Branch ¹3 p %g)g S"RC U. S. Nuclear Regulatory Commission Washington, D. C. 20555

.RQ~BZg~ 10 Re: Nine Mile Point Unit Docket No. 50-220 l ItI<~1 S,cIb Dec4I C4g ly DPR-63 r~

Dear Mr. Lear:

Attached is information concerning a request made by members of your staff during an October 28, l976 telephone conversation. This information concerns the Plant Unique Analysis Report for Torus Support System and Attached Piping for Nine Mile Point Nuclear Power Station.

Very truly yours, NIAGARA MOHAWK POWER CORPORATION SCHNEIDER Vice President Electric Production MGM/sz Attachment

k I ll,g 4.

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Question 1

a. Vhy did the upward displacement of'he torus decrease when the .normalizing factor used increased from 0.375 to 1.0 (Figure 3-9, Mark I'ontainment Evaluation Short Term Program Final Report, Addendum 3)?

b. What is thd correlation between anchor bolt strain and up-ward di splacement?

"R~es anse

a. The original'lant unique analysis did not include damping in the 1-D model. Two percent 'critical damping as structure damping is now being used. Also, a slight 'error in the elastic modulus of the bolt was corrected.These changes resulted in lower displacements.

b. Due to the modeling of'he nonlinear anchor bolt element (1) the element stress-strain relationship approximates the load-'deflection'of the actual anchor as of the "concrete. Figure 13( )shows it is pulled.'out the equivalent stress-strain diagram. It may be seen, that the equivalent material is much "softer" than the carbon steel anchor bolt. To obtain the anchor bolt strain, we used the following relati onshi p a

C E

where strain F/A maximum upward force anchor bolt cross-section area "actual" modulus of anchor bolt material = 27.9(10)~ psi (1) Plant Unique Analysis Report for Torus Support System and Attached Piping for Nine Mile Point Nuclear Power Station

4 Question 2 Document the effects of parameter changes and increased submergence on the pipe stresses and the ability of the piping to withstand the Loss of Coolant Accident.

R~es nse Differ'ential support motion during a Loss of Coolant Accident will induce pipe stresses. Tables 11 and 12(1) show'that these stresses (calculated on an elastic basis) are well within the code allowable values. Studies done for increased submergence and parameter .

changes show decreased upward displacement of the torus and, hence, decreased differential support motion (see Question la). Therefore, t'e pipe stresses due to increased submergence and parameter changes will be reduced. Xt is concluded that pipe stresses are acceptable for all cases..

(1) Same as Question I.

1 Question 3

a. Explain why the upward displacement and column forces de-creased when the downcomer submergence was increased;

b. Explain why strength ratios were reduced in some cases and provide method for calculating revised strength ratios.

Also, give revised tables of strength ratios. t

~Res sse

a. This is basically due to the change in arrival time of the vent header loads. A large downward load in the vent header columns now occurs when the mass in the 1<<D model is moving upward. Hence, t'e vent header column load now counteracts the motion of the mass. An analysis was performed using the same arrival time as used in Plant Unique Analysis Report for Torus Support System and Attached

~ Piping for Nine Mile Point Nuclear Power Station for in-creased downcomer submergence (3'-3") . The response is approximately the same as that for 3'-0" submergence.

b. As seen in Table 9( ), the strength ratios for the ring girder and the inner column were at their limits for the conditions analyzed in the Short Term Program report. The ring girder strength capaci ty was increased by using the material certification to obtain a greater yield stress.

This was increased from 32 ksi to 40.8 ksi. The strength capacities were based on 2 times yield stress.

Column capacities were increased by taking advantage of the Short, Term Program criteria. The ASME Code, Section III, was used for the original evaluation in Table 9( ). There-fore, it columns.

was possible to reduce the strength ratios of the The methods used for finding the effects of parameter changes and submergence changes on the plant unique analysis are essentially the same as those discussed with General Electric on September 24, 1976. The downward load phase and the upward load phase of the Loss of Coolant Accident transient were treated separately.

(1) Same as Question l.

C I j

R~es nse (Conti need)

b. Continued For the base case analysis, downward load phase, new values

=for loads in the torus support columns were, computed as follows:

New M

New Down (PD Dyn.

+ (PD L

+ Ph t ) +

Column Old V M

Load Down p + p Seismic h Abater Sei'smi c where:

New M Revised value for the load factor Md down Down as a result of the increased submergence and/or revised plant geometry factors.

Old- Value of'ddown used in plantunique M

Down analysis report ..

p The load in,,the torus support column due Dyn to the pool swell dynamic loading as reported in the plant unique analysis report.

Load in column due to weight of water D.L. plus steel as reported in the plant unique analysis report.

p h Water Zncrease in water dead weight due to higher water level (per column).

P ..

Seismic

= Load in column due to horizontal and vertical seismic as reported in plant unique analysis report.

t R~'es onse (Conninnedi

b. Continued p I'ncrease in column seismic load h, Vater due to horizontal and vertical Seismic 'ccelerations acting on 6 water mass.

Having established'new torus support column loads in 'this manner, a ratio was computed as follows:

New Col umn Load Old p

Column Load The factor "R" was then used to compute new "strength ratios" (SR) for components in the torus support structure load path, such as:

a) Torus Support Column b) Connection of torus support column to torus shell c) Connection at base of torus support column.

d) Tor'us shell adjacent to column connection e) Rei nforci ng ring at torus mi tered joint.

The original evaluation for the base case was given in Table 9 (l)

The revised results are presented in Tables A, B, and C (attached) and show the-revised evaluations. All strength ratios are within the allowable limits. For the upward load phase, the l-D model was rerun. Because of the generally lower response, the resulting forces and stresses were less than those reported(l). There-fore, the strength ratios are within the allowable limits.

(l) Same as Question l.

t t

TABLE A SUHMARY OF ANALYSIS RESULTS BASE CASE LOAD hP =~1)~si HAXIHUH DOWN LOADS For 3'-3" Submer ence Component Load/Stress Strength txJ Evaluation CU O Ratio M 0 IM CU c( O Ch 'r 5- Calculated Capacity Act. Allow.

Ring Gi'rder Stress, psi, Hembrane + Bending X. 34,800 81,600 .43 .50

'hear X 9,170 40,800 ..23 .50, Torus Shell Stress, psi Hembrane + Bending 21,700 64,000 .33 .50 Shear 15,600 40,800 .,38 .50 Column-Torus Weld Joint Inner Column Web Weld (kips) 508.2 678.0 .75 1.0 Flange Weld (in.-kips) (X 125.7 2,213.0 .05 1.0 65.5 700.0 .10 ,1.0 Outer Column Web Weld (kips) 595.1 678.0 .87 1.0 Flange Weld (in.-kips) IX 201 ' 2,213.0 .09 1.0

.158.7 700.0 1.0 Column =Buckling Inner Column Equation 19 X N/A N/A .40 0;5 Equation 20 N/A N/A N/A N/A N/A Outer Column '/A Equation 19 N/A .38 0.5 Equation 20 i'/A N/A N/A N/A Column Base Joint Inner Column Down Load (kips) 510.2 1602.0 .31 .50 Up Load (kips) 107.0* .461.45 .23 .50 Outer Column Down Load (kips) X 597. 2 1602.0 .37 .50 Up Load (kips) X 95,6* 4,61. 45 .21 .50

• Conservatively computed by mul.ti'plying values in original Plant Unique Analys'is Table 9 by

4 I

C'

TABLE B

SUMMARY

OF ANALYSIS RESULTS BASE CASE LOAD aP =~lysi MAXIMUM DOWN LOAI)S For 4'-0" Submer ence Component Load/Stress Strength w ii) Ratio Evaluation g O0

.V)

Calculated Capacity Act. "Al 1 ow.

Ring Girder Stress, psi Membrane + Bending 39,300 81,600 .48 .50 Shear 10,300 40,800 .25 .50 Torus Shell Stress, psi Membrane + Bending 24,500 64,000 .38 .50

.Shear 17,600 40,800 .43 .50 Column-Torus Weld Joint Inner Column Web We'd (kips) 573.4 678.0 .85 1.0 Flange Weld (in.-kips) 138.4 2,213.0 .05 1.0 73.9 700.0 .11 1.0 Outer Column tleb Weld (kips) 671.6 678.0 .99 1.0 Flange Weld (in.-kips) 227.0 2,213.0 .10 1.0 179.1 700.0 .26 1.0 Column Buckling Inner Column Equation 19 X N/A N/A .47 0.5 Equati'on 20 N/A N/A N/A N/A N/A'.5 Outer Column Equation 19 X N/A N/A ,44 Equation 20 N/A N/A N/A '/A . N/A Column Base Joint Inner. Column Down Load (kips) 573.4 1602.0 .36 .50 Up Load (ki'ps) 123.6* .461.45 .27 .50

.Outer Column'own Load (kips) ,671. 6 1602.0 ~ 42 .50 110.3* 461.45 .24 .50 Up t.oad (kips)

• Conservatively computed by multiplying values in original Plant Unique Analysis Table 9 by

TABLE C SUtlMARY OF ANALYSIS RESULTS BASE CASF. LOAD hP =~1 )si MAXIMUM DOWN LOADS For 4!-6" Submer ence Component I Load/Stress Strength UJ Qj ti Eva1 ua on 0 O S

CJ Ratio C/l cC 0

O I l/l 'rS-Ca 1 cul a ted Capacity Act. Allow.

Ring Girder Stress, psi Meoibrane + Bending X 34,800 81,600 .43 '.50

'hear X 9,170 40',uaO .23 .50 Torus'Shell Stress, psi 2'J,700 64,000 .33 .50 Membrane + Bending X .

X 15,600 40,800 . 38,. .50 Shear Column-Torus Weld Joint Inner Column Web He'd (kips) 678;0 .75 1.0 Flange Weld (in.-kips) ',213,0

.05 1.0

~

. 700.0 10 1.0 Outer Column '87 Web Meld (kips) 1.0 Flange Weld (in.-kips) z,NR:8 1.0 158.7 700. 0 1.0 Column Buckling Inner Column Equation 19 X N/A N/A .40 0.5 Equation 20 N/A N/A N/A N/A N/A Outer Column

'quation 19 N/A ~

~

N/A .38 0.5 Equation 20 /A N/A N/A N/A N/A Column Base Joint Inner Column Down Load (kips) X 508.2 1602.0 ,31, .50 Up Load (kips) X 124.7* .461.45 .50 Outer Column Down Load (kips) X 595.1 1602.0 .37 .50 Up Load (kips) X ill.3+ 461.45;24 .50

• Conservatively computed by multiplying values in original Plant Unique Analysis Table 9 by

0 ~ '