ML022660245

Response to Request for Additional Information: Safety Injection Tank Verification Frequency

ML022660245
Person / Time
Site:	Calvert Cliffs
Issue date:	09/18/2002
From:	Katz P Constellation Energy Group
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TAC MB3974, TAC MB3975
Download: ML022660245 (15)

Text

Peter E. Katz Vice President Calvert Cliffs Nuclear Power Plant Constellation Generation Group, LLC 1650 Calvert Cliffs Parkway Lusby, Maryland 20657 410 495-4455 410 495-3500 Fax Constellation Energy Group September 18, 2002 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:

REFERENCE:

Document Control Desk Calvert Cliffs Nuclear Power Plant Unit Nos. 1 & 2; Docket Nos. 50-317 & 50-318 Response to Request for Additional Information:

Safety Injection Tank Verification Frequency (TAC Nos. MB3974 and MB3975)

(a)

Letter from C. H. Cruse (CCNPP) to Document Control Desk (NRC),

dated January 31, 2002, License Amendment Request: Safety Injection Tank Verification Frequency In the Reference (a), Calvert Cliffs Nuclear Power Plant requested a change to the method for complying with the sampling surveillance in the Technical Specifications for the Safety Injection Tanks (SITs). In a phone call held on August 21, 2002, the Nuclear Regulatory Commission Staff requested that we respond to several questions concerning that amendment request. The Attachment (1) contains the requested information.

In addition to the requested information, we have determined that the reliability of the SITs should be tracked under the Maintenance Rule. Appropriate goals will be set for the SITs based on the boron concentration from SIT samples.

The information provided by this letter does not change the conclusions of the No Significant Hazards Determination contained in the referenced letter.

0

/

Document Control Desk September 18, 2002 Page 2 Should you have questions regarding this matter, we will be pleased to discuss them with you.

Very truly yours, STATE OF MARYLAND COUNTY OF CALVERT

TO WIT:

I, Peter E. Katz, being duly sworn, state that I am Vice President - Calvert Cliffs Nuclear Power Plant, Inc. (CCNPP), and that I am duly authorized to execute and file this License Amendment Request on behalf of CCNPP. To the best of my knowledge and belief, the statements contained in this document are true and correct. To the extent that these statements are not based on my personal knowledge, they are based upon information provided by other CCNPP employees and/or consultants. Such information has been reviewed in accordance with company practice and I believe it o be reliable.

Subscribed and sworn before me, a Notary Public in and for the State of Maryland and County of this 1 day of A

• -/i,4,002. [I~ u'*

LJA WITNESS my Hand and Notarial Seal:

My Commission Expires:

PEK/PSF/bjd

Attachment:

Notary Public OR !01a1lO (1)

Response to Request for Additional Information:

Safety Injection Tank Verification Frequency cc:

J. Petro, Esquire J. E. Silberg, Esquire Director, Project Directorate I-1, NRC D. M. Skay, NRC H. J. Miller, NRC Resident Inspector, NRC R. I. McLean, DNR

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION:

SAFETY INJECTION TANK VERIFICATION FREQUENCY Calvert Cliffs Nuclear Power Plant, Inc.

September 18, 2002

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION:

SAFETY INJECTION TANK VERIFICATION FREQUENCY NRC Question 1 The frequency of a large break loss-of-coolant accident (LOCA) is assumed to be 2E-6/yr. It is stated that this frequency is derived from a log normal interpolation of the data provided in NUREG/CR-5750 for large break LOCAs. However, it is not clear how the 2E-6/yr frequency was derived. NUREG/CR-5750 recommends a mean value of 5E-6/yr for large break frequency in PWRs. Please clarify.

CCNPP Response The NUREG/CR-5750 large break LOCA frequency is based on LOCA break sizes between a 6" diameter pipe and double-ended rupture.

The Calvert Cliffs Nuclear Power Plant large LOCA frequency is based on a break size between 0.5 ft2 (9.57" diameter pipe) and double-ended rupture.

The NUREG/CR initiating event frequency for small break LOCAs is about 100 times larger than the large break LOCA. This data indicates that the likelihood of a break logarithmically decreases as the break size increases. The log of the pipe diameters for the NUREG verses the frequency of break data was least squares fit (all points were used). This fit was used to determine the equivalent initiating event frequency for the Calvert Cliffs Nuclear Power Plant large break LOCA range.

NRC Question 2 On page 4 it is stated:

"The SIT [safety injection tank] boron concentration sample data is evaluated using data after these

[check valve seat] replacements. This replacement reduced the amount of leakage into the SITs. The SIT concentration sample data is evaluated using data after these replacements... there is less than a 0.2% chance that the boron concentration will fall below 2300 ppm on a single SIT given monthly surveillance."

The staff needs more detailed information about the data and the approach used to calculate the likelihood of low (below 2300 PPM) boron concentration given current and proposed surveillance requirements.

This additional information should include all data points used, a brief description of the "median ranking method," as well as the major steps and important intermediate results needed to understand what and how was done.

CCNPP Response The likelihood of a boron concentration below 2300 PPM was determined using the median rank method. For example:

Rank Data Median Rank (j)

(PPM)

(j-0.3)/(n+0.4) 1 2394 0.20%

2 2453 0.48%

3 2459 0.77%

4 2465 1.05%

352 2695 99.80%

The risk analysis contained 352 data points (i.e., n=352). There were no samples that fell below 2300 PPM (i.e., j=l). Therefore, the rank associated with the first point would be 0.2%. This is conservative, as the lowest PPM in the data was 2394 PPM.

I

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION:

SAFETY INJECTION TANK VERIFICATION FREQUENCY The next step in the risk evaluation is determining what the concentrations would be with a six-month interval. The base assumption is that the number of gallons of Reactor Coolant System (RCS) fluid that leaks into the SITs is proportional to the surveillance interval. For example, if 20 gallons of RCS fluid enters the SIT in a one-month interval, then 120 gallons would enter the SIT in a six-month interval.

On the surface, this conservative assumption would seem to mean that the change in boron concentration between surveillance tests would be proportionally larger. For example, a 10 PPM reduction in boron concentration in a one-month interval would represent a 60 PPM reduction for a six-month interval. But with the RCS boron concentration dropping due to normal operation, the change is actually larger. For example, a 10 PPM change in SIT concentration in the first month following an outage would take many more gallons of RCS fluid to accomplish than a 10 PPM change in SIT concentration in the sixth month after the outage. Considering this effect, the delta change in PPM is considered to be 7.6 times larger during the six-month interval (e.g., a 10 PPM becomes a 76 PPM change).

Excerpts for median ranking for the estimated six-month interval testing are:

Median Rank Rank Order Data Percentile (j)

(PPM)

(j-0.3)/(n+0.4) 1 1901 0.20%

2 2005 0.49%

3 2107 0.78%

8 2302 2.24%

344 3807 99.80%

As some of the data was used to calculate the delta interval for the last data point (i.e., four SITs per Unit). This ranking has only 344 data points (i.e., 344=352-8). This conservative approach yields a 2% likelihood that the boron concentration will fall below 2300 PPM. Complete ranking data and results are given in Table 1.

NRC Question 3 On page 2 it is stated:

"To justify this proposed change, the SIT levels, volume additions, leakage in, leakage out, and sample concentrations (for the RCS and SITs) were evaluated for both units for a six month period from July 1, 1999 to December 31, 1999. A review has shown this period to be representative of SIT behavior since 1997."

(a) Please explain how the review has shown that the data for those six months are representative for the entire period since the valve seats have been replaced. Were data from this six-month period only used in the risk assessment?

(b) Were there any instances, since valve seat replacement, where the boron concentration was found by sampling to be close or below 2300 PPM?

2

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION:

SAFETY INJECTION TANK VERIFICATION FREQUENCY (c) Were there any instances, since valve seat replacement, where the in-leakage flow rate was such that if it had been allowed to continue for six months without proper boron addition would cause the SIT boron concentration to fall below 2300 PPM?

Please explain and provide data to support your statements, as needed.

(d) The table provided in page 2 includes data for a six-month period and lists boron concentration at the beginning and the end of such period. This information does not show whether there would be instances of low boron concentration at the end of the six-month period if the information from the monthly sampling had not been available. Low boron concentration at the end of the six-month period could occur since leakage out of the tank can mask leakage into the tank and proper addition of boron would not have occurred without the monthly sampling. Please explain and provide data to support your conclusion.

CCNPP Response 3(a) Sample data for the entire period since the valve seats were replaced was reviewed. No unusual data perturbations were noted. The trend noted in the chosen six month period was consistent with trends for the entire period since the valve seats were replaced.

3(b) There are no instances, since valve seat replacement, when the boron concentration was found to be near or below 2300 PPM.

3(c) On March 2, 1999, the level in the No. 21A SIT had increased 10 inches and the tank was sampled in accordance with existing procedures.

That sample was found to have a boron concentration of 2394 PPM. The tank was then borated to 2465 PPM. At no other time since valve seat replacement has the level in the tanks changed enough that samples were required to be taken.

Boron concentration has not been adjusted in the tanks at any other time.

3(d) The data in the Table on page 2 shows the boron concentration in each tank after a six month period. No changes in boron concentration were made by the operators during that six month period.

If information from the monthly samples had not been available, the results at the end of the six month period would have been the same.

Makeup to the SITs is done to control level in the tanks, not as a means of controlling boron concentration.

Water is added to the SITs from the refueling water storage tank, whose boron concentration is controlled by Technical Specifications. Also, prior to any water addition to the SITs, the boron concentration of the water being added is determined. This ensures that water being added for level control is always adequately borated. With the exception of the instance noted in answer 3(c), it has not been necessary to adjust the boron concentration in any SIT since valve seat replacement.

Although actual experience indicates that with a six-month surveillance interval none of the samples would fall below 2300 PPM, the conservative calculation used in the risk analysis indicates that 2%

of the 352 samples would fall below 2300 PPM. It is important to stress the conservative nature of the risk calculation. No credit is taken for the operators' ability to monitor SIT level changes and take appropriate action. The most likely cause of boron concentration changes in the SIT is due to RCS in-leakage.

As the SIT levels are monitored by operations, the actual likelihood of the SIT concentration falling below 2300 PPM is far lower than the number used in the risk assessment.

3

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION:

SAFETY INJECTION TANK VERIFICATION FREQUENCY TABLE I Boron Concentration Median Rank Results Rank Order 1

2 3

4 5

6 7

8 9

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 Actual Data 1 test per month Boron in (in ppm) 2394 2453 2459 2465 2467 2468 2470 2477 2480 2487 2489 2492 2492 2494 2494 2497 2499 2499 2500 2510 2511 2511 2511 2512 2513 2519 2520 2521 2521 2521 2521 2522 2522 2525 2526 2529 2531 2532 2535 2536 Median Rank Percentile 0.20%

0.48%

0.77%

1.05%

1.33%

1.62%

1.90%

2.19%

2.47%

2.75%

3.04%

3.32%

3.60%

3.89%

4.17%

4.46%

4.74%

5.02%

5.31%

5.59%

5.87%

6.16%

6.44%

6.73%

7.01%

7.29%

7.58%

7.86%

8.14%

8.43%

8.71%

9.00%

9.28%

9.56%

9.85%

10.13%

10.41%

10.70%

10.98%

11.27%

Rank Order 1

2 3

4 5

6 7

8 9

10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 4

Projected Data (NOT Actual) 2 tests per year Boron in (in ppm) 1901 2005 2107 2136 2175 2263 2275 2302 2334 2361 2367 2377 2383 2384 2394 2394 2394 2397 2398 2398 2400 2403 2403 2404 2407 2408 2411 2413 2413 2422 2426 2426 2427 2428 2428 2430 2436 2439 2441 2443 Median Rank Percentile 0.20%

0.49%

0.78%

1.07%

1.36%

1.66%

1.95%

2.24%

2.53%

2.82%

3.11%

3.40%

3.69%

3.98%

4.27%

4.56%

4.85%

5.14%

5.43%

5.72%

6.01%

6.30%

6.59%

6.88%

7.17%

7.46%

7.75%

8.04%

8.33%

8.62%

8.91%

9.20%

9.49%

9.79%

10.08%

10.37%

10.66%

10.95%

11.24%

11.53%

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION:

SAFETY INJECTION TANK VERIFICATION FREQUENCY TABLE I Boron Concentration Median Rank Results Rank Order 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 Actual Data I test per month Boron in (in ppm) 2536 2537 2539 2542 2542 2544 2544 2547 2547 2549 2556 2561 2562 2564 2565 2567 2569 2573 2575 2576 2576 2576 2583 2584 2585 2585 2585 2585 2587 2588 2593 2593 2595 2597 2597 2597 2598 2599 2600 2600 Median Rank Percentile 11.55%

11.83%

12.12%

12.40%

12.68%

12.97%

13.25%

13.54%

13.82%

14.10%

14.39%

14.67%

14.95%

15.24%

15.52%

15.81%

16.09%

16.37%

16.66%

16.94%

17.22%

17.51%

17.79%

18.08%

18.36%

18.64%

18.93%

19.21%

19.49%

19.78%

20.06%

20.35%

20.63%

20.91%

21.20%

21.48%

21.77%

22.05%

22.33%

22.62%

Rank Order 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 5

Projected Data (NOT Actual) 2 tests per year Boron in (in ppm) 2445 2448 2453 2454 2461 2464 2465 2467 2471 2473 2474 2477 2481 2483 2485 2486 2488 2489 2494 2495 2496 2496 2497 2497 2503 2504 2505 2506 2515 2515 2522 2526 2527 2527 2529 2531 2532 2532 2532 2532 Median Rank Percentile 11.82%

12.11%

12.40%

12.69%

12.98%

13.27%

13.56%

13.85%

14.14%

14.43%

14.72%

15.01%

15.30%

15.59%

15.88%

16.17%

16.46%

16.75%

17.04%

17.33%

17.62%

17.92%

18.21%

18.50%

18.79%

19.08%

19.37%

19.66%

19.95%

20.24%

20.53%

20.82%

21.11%

21.40%

21.69%

21.98%

22.27%

22.56%

22.85%

23.14%

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION:

SAFETY INJECTION TANK VERIFICATION FREQUENCY TABLE 1 Boron Concentration Median Rank Results Rank Order 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 Actual Data I test per month Boron in (in ppm) 2601 2602 2602 2602 2603 2603 2604 2604 2604 2604 2604 2604 2605 2605 2605 2605 2606 2606 2608 2608 2609 2610 2610 2611 2611 2611 2611 2613 2613 2613 2613 2614 2615 2615 2615 2615 2616 2616 2616 2616 Median Rank Percentile 22.90%

23.18%

23.47%

23.75%

24.04%

24.32%

24.60%

24.89%

25.17%

25.45%

25.74%

26.02%

26.31%

26.59%

26.87%

27.16%

27.44%

27.72%

28.01%

28.29%

28.58%

28.86%

29.14%

29.43%

29.71%

29.99%

30.28%

30.56%

30.85%

31.13%

31.41%

31.70%

31.98%

32.26%

32.55%

32.83%

33.12%

33.40%

33.68%

33.97%

Rank Order 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 6

Projected Data (NOT Actual) 2 tests per year Boron in (in ppm) 2534 2536 2537 2538 2538 2540 2540 2545 2548 2548 2548 2551 2556 2556 2558 2559 2559 2560 2560 2562 2563 2563 2563 2563 2568 2570 2570 2571 2572 2572 2573 2573 2575 2576 2576 2576 2580 2580 2581 2583 Median Rank Percentile 23.43%

23.72%

24.01%

24.30%

24.59%

24.88%

25.17%

25.46%

25.75%

26.05%

26.34%

26.63%

26.92%

27.21%

27.50%

27.79%

28.08%

28.37%

28.66%

28.95%

29.24%

29.53%

29.82%

30.11%

30.40%

30.69%

30.98%

31.27%

31.56%

31.85%

32.14%

32.43%

32.72%

33.01%

33.30%

33.59%

33.89%

34.18%

34.47%

34.76%

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION:

SAFETY INJECTION TANK VERIFICATION FREQUENCY TABLE 1 Boron Concentration Median Rank Results Rank Order 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 Actual Data I test per month Boron in (in ppm) 2617 2617 2618 2618 2618 2619 2619 2619 2620 2620 2620 2621 2621 2621 2622 2622 2622 2622 2623 2623 2623 2624 2624 2625 2626 2626 2627 2627 2628 2628 2628 2628 2628 2628 2628 2628 2629 2629 2629 2630 Median Rank Percentile 34.25%

34.53%

34.82%

35.10%

35.39%

35.67%

35.95%

36.24%

36.52%

36.80%

37.09%

37.37%

37.66%

37.94%

38.22%

38.51%

38.79%

39.07%

39.36%

39.64%

39.93%

40.21%

40.49%

40.78%

41.06%

41.35%

41.63%

41.91%

42.20%

42.48%

42.76%

43.05%

43.33%

43.62%

43.90%

44.18%

44.47%

44.75%

45.03%

45.32%

Rank Order 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 7

Projected Data (NOT Actual) 2 tests per year Boron in (in ppm) 2583 2584 2584 2584 2585 2585 2587 2587 2588 2591 2594 2594 2594 2594 2595 2595 2596 2597 2597 2598 2598 2599 2599 2600 2600 2601 2602 2602 2602 2603 2603 2604 2605 2605 2607 2608 2609 2609 2610 2612 Median Rank Percentile 35.05%

35.34%

35.63%

35.92%

36.21%

36.50%

36.79%

37.08%

37.37%

37.66%

37.95%

38.24%

38.53%

38.82%

39.11%

39.40%

39.69%

39.98%

40.27%

40.56%

40.85%

41.14%

41.43%

41.72%

42.02%

42.31%

42.60%

42.89%

43.18%

43.47%

43.76%

44.05%

44.34%

44.63%

44.92%

45.21%

45.50%

45.79%

46.08%

46.37%

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION:

SAFETY INJECTION TANK VERIFICATION FREQUENCY TABLE I Boron Concentration Median Rank Results Rank Order 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 Actual Data I test per month Boron in (in ppm) 2631 2631 2631 2631 2631 2632 2632 2632 2633 2633 2633 2633 2634 2634 2634 2634 2634 2634 2634 2634 2634 2634 2634 2635 2635 2635 2635 2635 2635 2636 2636 2636 2636 2636 2637 2637 2637 2637 2637 2638 Median Rank Percentile 45.60%

45.89%

46.17%

46.45%

46.74%

47.02%

47.30%

47.59%

47.87%

48.16%

48.44%

48.72%

49.01%

49.29%

49.57%

49.86%

50.14%

50.43%

50.71%

50.99%

51.28%

51.56%

51.84%

52.13%

52.41%

52.70%

52.98%

53.26%

53.55%

53.83%

54.11%

54.40%

54.68%

54.97%

55.25%

55.53%

55.82%

56.10%

56.38%

56.67%

Rank Order 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 8

Projected Data (NOT Actual) 2 tests per year Boron in (in ppm) 2612 2612 2613 2613 2613 2614 2614 2614 2615 2617 2618 2619 2620 2620 2620 2621 2621 2621 2624 2624 2624 2625 2625 2625 2625 2626 2627 2627 2627 2627 2628 2628 2628 2629 2629 2629 2630 2631 2631 2632 Median Rank Percentile 46.66%

46.95%

47.24%

47.53%

47.82%

48.11%

48.40%

48.69%

48.98%

49.27%

49.56%

49.85%

50.15%

50.44%

50.73%

51.02%

51.31%

51.60%

51.89%

52.18%

52.47%

52.76%

53.05%

53.34%

53.63%

53.92%

54.21%

54.50%

54.79%

55.08%

55.37%

55.66%

55.95%

56.24%

56.53%

56.82%

57.11%

57.40%

57.69%

57.98%

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION:

SAFETY INJECTION TANK VERIFICATION FREQUENCY TABLE 1 Boron Concentration Median Rank Results Rank Order 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 Actual Data 1 test per month Boron in (in ppm) 2638 2638 2638 2638 2638 2638 2639 2639 2639 2639 2639 2640 2640 2640 2640 2640 2640 2640 2640 2640 2641 2641 2641 2641 2642 2642 2642 2642 2642 2643 2643 2643 2643 2643 2644 2644 2644 2644 2644 2644 Median Rank Percentile 56.95%

57.24%

57.52%

57.80%

58.09%

58.37%

58.65%

58.94%

59.22%

59.51%

59.79%

60.07%

60.36%

60.64%

60.93%

61.21%

61.49%

61.78%

62.06%

62.34%

62.63%

62.91%

63.20%

63.48%

63.76%

64.05%

64.33%

64.61%

64.90%

65.18%

65.47%

65.75%

66.03%

66.32%

66.60%

66.88%

67.17%

67.45%

67.74%

68.02%

Rank Order 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 9

Projected Data (NOT Actual) 2 tests per year Boron in (in ppm) 2633 2634 2634 2634 2634 2634 2635 2636 2637 2638 2639 2640 2643 2643 2644 2644 2644 2644 2645 2645 2645 2645 2646 2646 2647 2647 2647 2648 2648 2648 2649 2649 2650 2652 2652 2652 2652 2653 2653 2654 Median Rank Percentile 58.28%

58.57%

58.86%

59.15%

59.44%

59.73%

60.02%

60.31%

60.60%

60.89%

61.18%

61.47%

61.76%

62.05%

62.34%

62.63%

62.92%

63.21%

63.50%

63.79%

64.08%

64.37%

64.66%

64.95%

65.24%

65.53%

65.82%

66.11%

66.41%

66.70%

66.99%

67.28%

67.57%

67.86%

68.15%

68.44%

68.73%

69.02%

69.31%

69.60%

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION:

SAFETY INJECTION TANK VERIFICATION FREQUENCY TABLE I Boron Concentration Median Rank Results Rank Order 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 Actual Data I test per month Boron in (in ppm) 2644 2645 2645 2645 2645 2645 2645 2645 2646 2646 2646 2646 2646 2647 2647 2647 2647 2647 2647 2647 2647 2648 2648 2648 2648 2648 2648 2649 2650 2650 2650 2650 2650 2651 2651 2651 2651 2651 2652 2652 Median Rank Percentile 68.30%

68.59%

68.87%

69.15%

69.44%

69.72%

70.01%

70.29%

70.57%

70.86%

71.14%

71.42%

71.71%

71.99%

72.28%

72.56%

72.84%

73.13%

73.41%

73.69%

73.98%

74.26%

74.55%

74.83%

75.11%

75.40%

75.68%

75.96%

76.25%

76.53%

76.82%

77.10%

77.38%

77.67%

77.95%

78.23%

78.52%

78.80%

79.09%

79.37%

Rank Order 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 10 Projected Data (NOT Actual) 2 tests per year Boron in (in ppm) 2655 2656 2659 2661 2661 2662 2664 2667 2667 2667 2668 2669 2672 2672 2673 2673 2673 2673 2674 2675 2675 2676 2678 2679 2680 2680 2681 2681 2681 2681 2683 2683 2684 2685 2688 2688 2689 2689 2690 2691 Median Rank Percentile 69.89%

70.18%

70.47%

70.76%

71.05%

71.34%

71.63%

71.92%

72.21%

72.50%

72.79%

73.08%

73.37%

73.66%

73.95%

74.25%

74.54%

74.83%

75.12%

75.41%

75.70%

75.99%

76.28%

76.57%

76.86%

77.15%

77.44%

77.73%

78.02%

78.31%

78.60%

78.89%

79.18%

79.47%

79.76%

80.05%

80.34%

80.63%

80.92%

81.21%

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION:

SAFETY INJECTION TANK VERIFICATION FREQUENCY TABLE I Boron Concentration Median Rank Results Rank Order 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 Actual Data I test per month Boron in (in ppm) 2652 2652 2652 2652 2652 2652 2652 2652 2652 2652 2652 2652 2652 2653 2653 2653 2653 2653 2653 2653 2654 2654 2654 2654 2654 2654 2654 2654 2654 2654 2654 2655 2655 2655 2655 2655 2655 2656 2656 2656 Median Rank Percentile 79.65%

79.94%

80.22%

80.51%

80.79%

81.07%

81.36%

81.64%

81.92%

82.21%

82.49%

82.78%

83.06%

83.34%

83.63%

83.91%

84.19%

84.48%

84.76%

85.05%

85.33%

85.61%

85.90%

86.18%

86.46%

86.75%

87.03%

87.32%

87.60%

87.88%

88.17%

88.45%

88.73%

89.02%

89.30%

89.59%

89.87%

90.15%

90.44%

90.72%

Rank Order 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 11 Projected Data (NOT Actual) 2 tests per year Boron in (in ppm) 2691 2692 2692 2692 2692 2693 2697 2698 2699 2700 2702 2703 2706 2706 2707 2709 2714 2715 2716 2718 2718 2719 2719 2721 2726 2727 2731 2736 2738 2742 2742 2743 2744 2751 2752 2756 2756 2760 2765 2769 Median Rank Percentile 81.50%

81.79%

82.08%

82.38%

82.67%

82.96%

83.25%

83.54%

83.83%

84.12%

84.41%

84.70%

84.99%

85.28%

85.57%

85.86%

86.15%

86.44%

86.73%

87.02%

87.31%

87.60%

87.89%

88.18%

88.47%

88.76%

89.05%

89.34%

89.63%

89.92%

90.21%

90.51%

90.80%

91.09%

91.38%

91.67%

91.96%

92.25%

92.54%

92.83%

ATTACHMENT (1)

RESPONSE TO REQUEST FOR ADDITIONAL INFORMATION:

SAFETY INJECTION TANK VERIFICATION FREQUENCY TABLE I Boron Concentration Median Rank Results Rank Order 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 Actual Data I test per month Boron in (in ppm) 2656 2657 2657 2657 2657 2658 2658 2658 2658 2658 2659 2659 2659 2660 2660 2660 2660 2660 2661 2662 2662 2662 2662 2663 2663 2665 2667 2667 2692 2692 2692 2695 Median Rank Percentile 91.00%

91.29%

91.57%

91.86%

92.14%

92.42%

92.71%

92.99%

93.27%

93.56%

93.84%

94.13%

94.41%

94.69%

94.98%

95.26%

95.54%

95.83%

96.11%

96.40%

96.68%

96.96%

97.25%

97.53%

97.81%

98.10%

98.38%

98.67%

98.95%

99.23%

99.52%

99.80%

Projected Data (NOT Actual) 2 tests per year Boron in (in ppm) 2776 2780 2782 2785 2801 2804 2809 2810 2813 2866 2869 2874 2897 2927 2934 2969 3010 3117 3229 3253 3421 3441 3486 3807 12 Rank Order 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 Median Rank Percentile 93.12%

93.41%

93.70%

93.99%

94.28%

94.57%

94.86%

95.15%

95.44%

95.73%

96.02%

96.31%

96.60%

96.89%

97.18%

97.47%

97.76%

98.05%

98.34%

98.64%

98.93%

99.22%

99.51%

99.80%