ML19294A807
| ML19294A807 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 03/16/1979 |
| From: | Stallings C VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Parr O Office of Nuclear Reactor Regulation |
| References | |
| 150, NUDOCS 7903220217 | |
| Download: ML19294A807 (19) | |
Text
f VIRGINI A CL EC T RIC A N D PO W E R COM P AN Y, RIC HMON O, VIRGINI A 23261 March 16, 1979 Serial No. 150 FR/EJL Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation Docket No. 50-339 Attn:
Mr. O. D. Parr, Chief Light Water Reactors Branch No. 3 Division of Project Management U. S. Nuclear Regulatory Commission Washington, D. C.
20355
Dear Mr. Denton:
NORTH ANNA POWER STATION - UNIT 2 MODIFIED STARTUP PHYSICS TESTING PROGRAM - SUPPLEMENTAL INFORMATION In a letter (Serial No. 064) from myself to you dated February 5, 1979, Vepco identified several modifications that had been made to the initial Startup Physics Testing Program for North Anna Unit 2.
Subsequent to this, several telephone conversations have been held between members of the NRC and Vepco staf fs.
Based on these conversations, several changes and additions to the information contained in the attachments to our February 5,1979 letter were developed.
This information has been revised and is enclosed as Attachments 1 through 4 of this letter (these are page for page replacements).
Additionally, the NRC staff had several specific questions re-garding the Unit 2 startup physics testing program.
Their questions, together with our responses, are enclosed as Attachment 5.
Should you have any further questions or comments regarding this material, please contact us.
Very truly yours,
-l f. %b d(hc y')
C. M. Stallings, Vice President Power Supply and Production Operations Attachments cc:
Mr. James P. O'P.eilly Office of Inspection and Enforcenent, Region II 7 903 22 0,R/ 7
ATEACHMENT 1 UNIT 2 STARTLP PHYSICS TESTS A.
Ilo t 7ero Pouer Tests 1.
Reactivity computer checkout.
2.
Isothernal temperature coefficient at ARO.ind D-bank in (also D,C banks in if MTC for D-bank in is > 0 pcm/ F).
3.
Boron endpoints at AR0; D-bank in ; D,C-banks in; D, C, B-banks in; D, C, B, A-banks in; shutdown bank B in with all other rods out; and shutdown bank A in with all other rods out.
4.
Reactivity worths of all control and shutdown rod banks.
5.
Boron vorth over the range of control banks A through D moving during rod insertion and withdrawal.
6.
Power distribution neasurements for ARO and a-bank in.
B.
Power Ascension Tests 1.
30% power flux map.
2.
50% power flux map.
3.
Pseudo dropped rod test (RCCA D-10) and associated power distribution measurements at 50% power.
4.
Incore/Excore detector calibration flux maps at 75% power.
5.
APDMS flux maps at or below 95% power.
6.
Flux maps at 90% and 100% power (equilibrium conditions).
ATTACllMENT 2 PHYSICS TESTS TilAT llAVE BEEN DELETED FOR UNIT 2 A.
Ilo t Zero Power Tests 1.
Isothermal temperature coefficient at D,C-banks in: D,C,B-banks in; and D,C,B,A-banks in.
2.
Boron endpoint for the N-1 rods-in configuration.
3.
Reactivity Worth of N-1 rods.
4.
Pseudo-rod ejection and associated power distribution measurements.
B.
Power Ascension 1.
Pseudo-rod ejection and associated power distribution measurement at 30% power.
2.
Pseudo-dropped rod test (RCCA H-6) and associated power distribution measurement.
3.
Power coefficients.
4.
Integral power defect.
5.
Doppler-only power coefficients.
e ATTACIPiNT 3 SU*tAltY CF INIT 1 P'AStlRFD VA!.UFS, DrSICN V bins [riisTUN TO'IFAN( F, AND ACCID!NT ANAt.YSIS CRTIFRij IT1R PHYSTCS TFSTS TH AT HAVE REFN LET FTFD IT'R t3IT 2 thre 1M i t I M.fr,n V.atue ik~ f r.n Acc1A at An.ilysis Test fo w ription Cond i t ism Parameter Measure Value (not., Best-ci t imate)
Ta l e r.w e t'rit.rlon 1.
Iwther:ul Tem.perature Banks D.C in mT
-7.86 pcm/*F
-8.9 p :m/"F 13 pcm/4F
- -2.107 ser/"F Cosifici(nt Bai.ks D.C.B in g
-13.48 pcs/ F
-14.1 pen / F 33 pcm/"F 1 -2.1 % ner/"F Banks D.C.B.A. in g
-14.07 pcm/0F
-13.8 pcm/JF
+1 pcmi'F 1-2.135 pee /ef 2.
Boron F.ndpoint N-1 rods inserted C3 601 ppe 580 ppm t o pi'm
-xC :24COC!w 3
wl.cre s= 11.0S per. G -
3.
RoJ Worth N-1 rods I -1 8015 7893 pcm
+ 739 p: n.
(IN-1)/1.0y.57 0 r.a N
4.
pacuJo.-j ectcJ 11Z P, tank C at F
6.85 10.8 NA l i. u q
I -6" GI pcm 461 pcm 146 pem d 3-4 K 1. V.@ rt.
Control Rad 120 steps, h.ank D B
at 0 a.teps RCCA B-8 at 228 hteps.
30% power. ILank D Fq 2.1 2.1 NA 7.07 at 19'. i.t e p s, RCCA I _g 3 pcm 7 peu
! ! pi n.
(1 ;-M) X 1.tM g
tt-8 at 228 e.teps.
~10) t e u 1
5.
P ae w :o-d r..pp e d Csat o! lb.d 50'. pow r ha 1.62 I.70 NA a**
a RCCA H-6 I -6**
1 Pcm 145 pcm
+21 per
(!g.1,)x
,0; g g ll pn 6.
Power Coefficient 30% power (30/LQ)
-15.24 pcs/% power
- 14. 02 pc m/*. powe r
+4.5 7 pem/2 powr NA 50% power (3p/'Q?""'
-12.74 pcm/% power
- 13. 75 pcm/t powe r
+ 3.82 pcr /7 p..c r NA 75% power (3a/Sq)P #
-13.57 pcm/*. power
-13.39 pcm/% power I4.07 pem/t gewr A
90% power (3p/SQ)p,
-10.7.3 pcm/Z power
-13. 31 pcm/% powr
}3.21pcm/%powr NA 7.
Pow r De f ec t 0-100% power Reactivity Worth 1273 pcm 1299 pcm
+191 pc.s NA 8.
Doppler-only 30% power (Sp/3Q)["hyd -13.62 pcm/t power
-11. 35 pcm/% power
+4.09 pcm/t piw r Inferred value pit.s or Power Coefficient 50% power (30/3Q)afe5 red eini.s 3M unc.. int ;
pp er
-10.77 pcm/Z power
-10. 75 pcm/% power 13.23 per/Z powr must o er!.iy allow-75% power (3p/3Q Interred -11.08 pcm/% power
- 9.96 pcm/t power 13.32 pcm/* power ance ranee of FSAR Doppler Fis;ure 15.1,5.
- 0 power (3p/3Q) hp g - 7.59 pcm/% power
-9. 38 pcm/t power
+2.2:i pcm/Z power Fote: All inferrcJ f
J vc. lues f ell wit *.in ra%e of TSA3 Tip.ra 15.1-5, a..'.m en iL (allewin pace.
(Firu!. A., I)
- Accident an.41ysin valua referenced to hot full power.
- 1 _g = integrated reactivity worth of all control rods except the most reactiva rod (N-1).
3 I -8 = integrated reactivity worth of rod cluster control assembly (RCCA) S-8.
B T -6 = integrated reactivity worth of RCCA H-6 H
- Violation of design tolerance was evaluated to be insignificant due to las value of reactivity worth.
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N1F 14-1 ATTACRMENT 4 FSAR REVISION 14.0 INITIAL TESTS AND OPERATION This section presents material describing the scope of tests and operations performed over the time period when construction was sufficiently complete to operate and test individual components and systens through the acceptance-run at full power.
This tice period is divided into two categories.
a) Preoperational Testing - tests performed prior to the initial core loading and, b)
Initial Startup Testing - tests and operations from the initial core loading through the acceptance tests.
The preoperational and startup programs, as outlined in Tables 14.1-1 and 14.1-2 comply with the intent of Regulatory Guide 1.68,"Preoperational and Initial Startup Test Prograns for Water-Cooled Power Reactors," dated November 1973, in most cases, and utilizing the same wording as much as possible in order to more clearly address the NRC guide requirements.
The startup physics testing program for Unit 2 is described in the letters from Mr. C. M. Stallings (Vepco) to Mr. H. R. Denton (USNRC), dated February 5, 1979 (Serial No. 064) and March 16,1979 (Serial No. 150).
1TTACIDIENT 5 NRC QUESTIONS AND VEPCO'S RESPONSES REGARDING THE NORTH ANNA POWER STATION - UNIT 2 MODIFIED STARTUP PHYSICS TESTING PROGRAM
Question 1:
With resrect to Iten B. 3 on Attachrent I and Item B. 2 on, what is the reason for performing the pseudo dropped rod test with RCCA D s instead of RCCA H-6?
Response
This tes: was performed twice for Unit 1, one time using RCCA D-10 and the other time using RCCA H-6.
The evaluation of the results associated with these tests indicated that of the twc rods, RCCA D-10 resulted in the nore limiting radial power distribution and consequently had the minimum nargin to departure from nucleate boiling.
This was the basis for choosing RCCA D-10 for tne Unit 2 test.
Question 2:
Describe any known differences between the fuel and core of North Anna Unit I and the fuel and core of North Anna Unit 2.
Response
Three differences have been identified between the Unit 1 and Unit 2 fuel and core.
They are:
1) the location of the secondary sources within the core, 2) the part length control rods have been recoved, and 3) the fuel rods have been pre-pressurized to a different pressure.
The core locations of the secondary sources for Unit 1 and Unit 2 are shown in Figure A.S.2.a.
It is not anticipated that this change will lead to a measurable difference in the physics characteristics between the Unit 1 and Unit 2 cores.
The core location of the part length control rods for Unit 1 is shown in Figure A.5.2.b.
This change :111 not lead to a measurcable dif-ference in the physics characteristics between the Unit 1 and Unit 2 cores because the use of the part length control rods is not permitted during Unit 1 core operation.
It is planned that these rods will be removed from Unit 1 fo112 wing the end of Cycle 1 operation.
Unit 2 fuel has a pre-pressurization value that is approximately 50 psi lower than that used for Unit 1 fuel.
This difference will have no perceptible e:fect on the physics characteristics of the core.
In addition, an evaluation has shown that there will be no adverse impact on fuel or core performance.
FIGURE A.S.2.a SECONDARY SOURCE LOCATIONS i
R P
II L
K I
H C
F E
D C
II A
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11.
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locations for Unit 1 I
=
i locations for Unit 2
=
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FIGURE A.5.2.b P/sRT LENGTH CONTROL ROD LOCATIONS I;
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Question 3:
Describe any differences between the physics test methods that vere used for Unit 1 and the physics test methods that will be used for Unit 2.
Response
For Unit 1, the reactivity worth of shutdown bank B was determined with control banks A through D fully inserted into the core, and used the dilution /boration technique.
The worth of shutdown bank A was determined with control banks A through D and shutdown bank B fully inserted into the core.
Shutdown bank A underwent an exchange with the most reactive rod (RCCA B-8) followed by a dilution of the reactor coolant system in order to fully insert shutdown bank A.
For Unit 2, the reactivity worths of shutdown banks A and B will be determined individually with all other control rod banks out of the core.
The worth of shutdown bank A will be determined using the conventional dilution /boration technique.
A boron endpoint determination will be made for this control rod configuration. The worth of shutdown bank B will be determined by using rod exchange with one of the other control rod banks, and if necessary, dilution /boration of the reactor coolant system in order to reach the desired state point, i.e.,
shutdown bank B fully inserted with all other rods out.
A boron endpoint determination will be made for this control rod configuration.
Question 4:
For each of the startup physics tests that were performed for Unit 1 but are not going to be performed for Unit 2, give the technical basis for not performing those tests.
Response
The tests that are not going to be performed for Unit 2 are listed in Attachment 2.
For each of the tests listed, the test description that appears in Regulatory Guide 1.68 (November, 1973) is given together with the technical basis for not performing those tests.
A.1 Isotherral temperature coefficient at D, C-banks in ;
D, C, 3-banks in: and D, C, B, A-banks in Regulatory Guide Test Description - Moderator temperature re-activity coefficient measurement and defect measurement over the temperature range in which the reactor may be taken critical. -
The Regulatory Guide does not require the measurement of the mod-erator temperature coefficient for any specific set of control rod configu-rations.
However, the station Technical Specifications will require that a non-positive value for the moderator temperature coefficient be maintained during normal operation.
Based on the results of our design calculations and the Unit 1 moderator temperature coefficient test results, it is expected that performance of the moderator tcmperature coefficient tests with all-rods-out and with control bank D-in will be adequate to demonstrate a non-positive moderator temperature coefficient value and also provide enough data to estab-lish control rod withdrawal limits, should they be necessary.
The temperature coefficient measurements that were performed on Unit 1 with the control rods of D, C-1,.iks in ; D, C, B-banks in; and D, C, B, A-banks in were merely additional design check-points.
These are now considered to be extraneous tests and have been eliminated from the Unit 2 testing program.
A.2 noron endpoint for the N-1 rods-in con figurat ion Regulatory Guide Test Description - Determination of boron con-centration at initial criticality and reactivity allocation.
The Regulatory Guide does not specifically describe this test.
Additionally, our response to Question 3 alludes to the fact that the core will not be in the N-1 rods configuration during the physics testing pro-gram.
Boron endpoint determinations will be made following each control and shutdown rod bank reactivity measurement. We believe that the perfor-mance of these measurements adequately meets the intent of this section of the Regulatory Guide.
A.3 Reactivity worth of N-1 rods Test Description - Control rod reactivity worth determinations including verification of rod. nsertion limits to assure adequate shutdown margin.
As desribed in our response to Question 3, the reactivity worth of the control and shutdown rod banks will be teasured as part of the physics testing program.
The successful completion of these measurements will serve to verify the design model used to predict the reactivity worth of the rod banks and thus neet the intent of this section of the Regulatory Guide. Addi-tionally, che results of the tests performed on Unit 1 demonstrated that a large margin existed with respect to the shutdown margin limit.
A.4 Pseudo-rod ejection and associated power distrib'ition measurements (HZP)
Test Description - Pseudo rod ejection test to verify reactivity worth used in safety analysis.
As described in A.3 above, the successful completion of the rod bank reactivity worth measurements will verify the design model used to calculate rod worths, thus meeting the intent of this section of the Regulatory Guide.
Additionally, as indicated on Attachment 3, Item 4, the results of the test that was performed on Unit 1 demonstrated a large margin between the measured rod worth and the value used in the safety analysis.
B.1 Pseudo-rod ejection and associated power distribu~ 'on measurement at 30% power Test Description - Pseudo rod ejection test to verify safety analysis G* 107,, with full power rod configuration).
As described in A.3 above, the successful completion of the rod bank reactivity worth measurements will verify the design model used to calculate the rod worths, thus meeting the intent of this section of the Regulatory Guide.
Additionally, as indicated on Attachment 3, Item 4, the results of the test that was performed on Unit 1 demonstrated a large margin between the measured rod worth and the value used in the safety analysis.
.T. 2 Pseudo dropped rod test (RCCA H-6) and associated power distribution measurement R;gulatory Guide Test Description - Evaluation of flux asymmetry with single rod assembly (mily inserted and partially inserted be-low the control bank (50%) and evaluation of its ef fects on de-parture from nucleate boiling.
As described in our response to Ouestion 1, this test was performed tuice for Unit 1 - one time using RCCA D-10 and the other time ur.ing RCCA II-6.
For Unit 2, this test will be performed using the limiting rod, RCCA D-10.
Based on an evaluation of the Unit I test results, it has been determined that the successful completion of this test will be sufficient to meet the intent of this section of the Regulatory Guide, since no additional required infor-mation would be obtained as a result of repeating the test using RCCA H-6.
Additionally, as indicated on Attachment 3, Item 5, the results of the test that was performed on Unit I utilizing RCCA H-6 were acceptable.
B.3 Power Coefficient Tests B.4 Integral Power Defect B.5 Doppler-only power coefficients Regulatory Guide Test Description - Pouer reactivity coefficient evaluation (25%, 50%, 75%, 100%).
The NRC staff has deleted r.he requirement that power coefficient measurements be performed as part of the physics testing program for reload cores. Additionally, the Regulatory Guide does not specifically contain test descriptions for the integral power defect and the Doppler - only power coefficients.
As indicated on Lttac'..nent 3, Items 6, 7, and 8, and Figure A.3.1, the results of the tests tha: aere performed for Unit 1 were acceptable and verified the design model.
Question 5:
It is suggested that for the boron endpoint measurements and the rod bank react ivity worth measurements that, where appropriate, review cri-teria be established that compare the Unit 2 test results with the Unit 1 test results.
For each of these tests, list the specific review criteria that will be used. Also, indicate the action that will be taken if the re-view criteria are not met.
Response
The tests and the specific test review criteria that will be used are listed on Table A.S.I.
As described in our response to Question 3, the reactivity worth and boron endpoint measurements associated with shutdown banks A and B that will be performed for Unit 2, are not direct duplicates of the tests that were performed during the Unit 1 testing program. There-fore, a comparison to Unit I results would be inappropriate.
As stated in the FSAR and as required by the Vepco Nuclear Power Station Quality Assurance
>bnual, these test results will be reviewed and evaluated by the Station Nuclear Safety and Operating Committee.
Should the results of any of these tests fail to meet the review criteria, the Committee may decide to perform additional testing. This additional testing may be a repeat of the original test or may be the perfornance of a test that had been deleted from the Unit 2 physics testing program.
TABLE A.S.1 UNIT 2 BO?.ON ENDPOI:!T AND ROD WORTH REACTIVITY TESTS AND REVIEW CRITERIA Test Description Review Criteria Boron Endpoint
-ARO 1322 ppm 2$4 ppm
-D bank in 1193
$4
-D, C banks in 1075 t 54
-D, C, B banks in 884 i 24
-D, C, B, A banks in 781 24 Control Rod Worth
-D bank 1463 pcm i 110 pcm
-C bank 1303 98
-B bank 2036 t l53
-A bank 1309 98