Text

Submits Addl Info Re Meteorological Data in Response to NRC .Stability Persistence Summary Tables Encl
	ML20052H208
Person / Time
Site:	Seabrook
Issue date:	05/14/1982
From:	Devincentis J; PUBLIC SERVICE CO. OF NEW HAMPSHIRE, YANKEE ATOMIC ELECTRIC CO.
To:	Miraglia F; Office of Nuclear Reactor Regulation
References
	SBN-275, NUDOCS 8205200066
	Download: ML20052H208 (7)
	v • d • e

l SEABROO STATION lPUBLIC SERVICE Engineering Office:

Companyof New Hampshem 1671 Worcester Road Framingham, AAossachusetts 01701 (617) - 872 - 8100 May 14, 1982 SB'i-275 T.F. B 7.1.2 United States Nuclear Regulatory Commission Washington, D. C. 20555 Attention:

Mr. Frank J. Miraglia, Chief Licensing Branch #3 Division of Licensing

References:

(a) Construction Permits CPPR-135 and CPPR-136, Docket Nos. 50-443 and 50-444 (b) USNRC Letter, dated February 12, 1982, " Request for Additional Information," F. J. Miraglia to W. C. Tallman (c) PSNH Letter, dated March 12, 1982, " Response to 451 Series RAIs; (Accident Evaluation Branch; Meteorology Section)

Su bj ec t :

Submittal of RAI 451.14 (a); (Accident Evaluation Branch; Meteorology Section)

Dear Sir:

We have enclosed a response to the subject RAI which ycu forwarded in Reference (b).

It was indicated in Reference (c) that RAI 451.14 (a) would be submitted by May 17, 1982.

Very truly yours, YANKEE ATOMIC ELECTRIC COMPANY U

J. DeVincentis Project Manager Enclosure l

9205200066 820514

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PDR ADOCK 05000443

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451.14 A comparison of three years of on-site meteorological data (11/71 -

~{2.3) 10/72, 4/79 - 3/80 and 6/80 - 5/81 indicates significant (FSAR) variaaility in the frequency of atmospheric stability conditions, particularly for unstable (Pasquill types "A", "B" and "C") and slightly stable (Pasquill type "E") conditions. For example, for the period November 1971 - October 1972, unstable conditions were observed about 10% of the time, while slightly stable conditions were observed about 32% of the time. However, for the period April 1979 - March 1980, unstable conditions were observed about 21% of the time, while slightly stable conditions were observed only about 24% of the time. For the latest period of record (June 1980 - May 1981), unstable conditions were observed almost 27% of the time, with about 12% classified as extremely unstable (Pasquill type "A"), while slightly stable conditions were observed only about 17% of the time.

a.

Provide a discussion of the year-to year variability of unstable and slightly stable conditions at the Seabrook site, and discuss the reasonableness of the large fraction (in excess of 20%) of unstable conditions observed at Seabrook since April 1979, considering the atmospheric mechanisms for generating tharmal instability, the classification scheme used, the location of the meteorological tower and the surf ace characteristics around the tower, and the location of the site. Also indicate why the increased frequency of unstable conditions appears to occur at the expense of the fregnuncy of slightly stable conditions while the frequencies of other stability classes remain relatively ccastant from year-to year.

b.

Provide information on the persistence of each stability class in a form similar to Table 2B-5 in Appendix B of the FSAR for the periods April 1979 - March 1980 and June 1980 -

May 1981.

RESPONSE

a.

Seabrook RAI Table 451.02-3 indicates that the occurrence of unstable conditions recorded by the lower delta-temperature instrumentation increased from a frequency of 21.1% during 4/79 - 3/80 to a frequency of 26.9% during 6/80 - 5/81. This increase in recorded unstable conditions may be due in part to an intermittent problem with the instrumentation observed during periods of heavy precipitation. Beginning in mid-1980, the lower delta-temperature measurements began to occasionally indicate unstable conditions during rainy periods. By the beginning of 1981, persistent unstable conditions were being recorded during heavy precipitation periods, regardless of the time of day. This intermittent problem did not occur during regularly scheduled calibration and preventative maintenance visits to the site.

In an attempt to isolate the problem, the entire lower level delta-temperature system was replaced with spare parts in June 1981. The problem still persisted, however, and in a further attempt to isolate the problem, new cables were run between the tower and instrument shed in February 1982. At the time of this writing (April 1982), it appears the problem may have been resolved with the replacement of the cables.

2-An attempt was made to edit out the most unreasonable j

occurrences of unstable conditions by defining such periods as bad data..These periods of unreasonable occurrences of unstable _ conditions included the persistence of extremely unstable conditions throughout rainy nights, conditions which typically indicate the presence of slightly stable L

conditions. This editing may explain why there was a 4

a decrease of recorded occurrence of slightly stable conditions fros the 4/79 - 3/80 period to the 6/80 - 5/81 period. In spite of the editing of the obviously unrealistic, unstable conditions during heavy precipitation periods a slight bias towards unstable conditions may-still exist in the 6/80 -

5/81 lower delta-temperature data base.

Diff'erences in measured atmospheric stability conditions between-the 11/71 - 10/72 data base and the'later periods may have been partially due to changes in ground cover

~ The 11/71 - 10/72 data characteristics of the plant site.

base was collected before site construction began, and as i;

such, the plant site was covered with vegetation..A grass i

surface still remains under the tower, but many surrounding acres once containing fields and disturbed areas interspersed with hardwood and evergreeri forest have been replaced with barren dirt parking lots and construction areas. The vegetation present on the plant site during collection of the earlier data base would have produced less surface heating and a more stable atmosphere than the more recent dirt parking lots and construction areas.- Direct comparison of atmospheric stability conditions measured during the earlier period with the later periods is difficult due also to a difference ~ in instrumentation, measurement heights and data processing procedures.

b.

Stability persistence summaries for the periods April 1979 -

i March 1980 and June 1930 - May 1981 are provided in Tables 451.14-1 and 451.14-2, respectively.

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TABLE 451.14-1 (Sheet 1 of 2)

STABILITY PERSISTENCE

SUMMARY

i APRIL 1979-MARCH 1980 a.43-150 Foot Delta-Temperature STABILITY PERSISTENCE

SUMMARY

- NUMBER OF OBSERVATIONS AC PERCENT PROBABILITY STABILITY FERSISTENCE (H7JRS)

STABILITY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 0T.24 TOTAL A

111 51 31 12 13 3 7 2 3 2 1 0 0 0 0 0 0 0 0 0 0 0.0 0 0 236 47 69 S2 87 92 94 97 97 99 100 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9

297 100 47 22 8 2 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 476 62 83 93 98 100 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C

319 55 10 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 388 82 96 99 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 D

333 180 136 70 36 34 32 13 14 15 8 16 9 8 3 5 5 3 2 2 2 1 3 0 5(a) 937 36 55 69 77 81 84 88 89 91 92 93 95 96 96 97 97 98 98 99 99 99 99 99 99 100 a

E 322 133 73. 46 32 20 17 13 19 9 9 0 8 3 2 0 2 1 0 0 0 0 0 0 0 709 45 64 74 81 85 88 91 93 95 96 98 93 99 99 100 100 100 100 0 0 0 0 0 0 0 F

210 76 24 11 13 1 2 3 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 3:1 62 84 91 94 98 99 99 100 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

61 33 12 '12 6 11 9 4 3 3 4 2 0 0 0 0 0 0 0 0 0 0 0 0 0 160 38 59 66 74 78 84 90 93 94 96 99 100 0 0 0 0 0 0 0 0 0 0 0 0 0 TOTAL!653 628 333 177 108 71 67 35 40 29 22 18 17 !!

5 5 7 6 2 2 2 1 3 0 5 3247 (a)Of these 5 occurences of D stability which persisted over 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months s:

o one lasted 28 hours3.240741e-4 days 0.00778 hours 4.62963e-5 weeks 1.0654e-5 months o one lasted 32 hours3.703704e-4 days 0.00889 hours 5.291005e-5 weeks 1.2176e-5 months o one lasted 33 hours3.819444e-4 days 0.00917 hours 5.456349e-5 weeks 1.25565e-5 months o one lasted 40 hours4.62963e-4 days 0.0111 hours 6.613757e-5 weeks 1.522e-5 months o one lasted 44 hours5.092593e-4 days 0.0122 hours 7.275132e-5 weeks 1.6742e-5 months

.-i TABLE 451.14-1 (Sheet 2 of 2) b.

43-2C9 Foot Delta-Temperature STABILITY PERSISTENCE St9. lARY - NUMBER OF OBSEBATIONS AND PEPCENT PROBABILITY STABillTY PER51 STEN;E (HOURS)

STABILITY-1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 GT.24 TOTAL A

59 22 2 5 2 2 1 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 97 61 84 86 91 93 95 96 98 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 2

181 42 15 4 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 203 69 ?0 98 100 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C

233 90 34 19 4 0

.0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 380 61 85 94 99 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

265 165 123 75 44 38 25 17 17 8 13 14 5 67 5 3 2 5 2 3 1 0 1 12(a) 556 31 50 65 73 79 83 86 88 90 91 92 ?4 95 95 ?6 97 97 97 98 93 98 92 98 99 100 E

276 157 68 58 50 35 15 18 19 18 9 3 5 9 5 1 1

1 0 1 2 1 0 0 0 752

' 37 58 67 74 81 S6 88 90 93 ?5 96 97 97 98 99 99 99 99 '99 100 100 100 0 0 0 F

185 83 38 18 10 6 4 0 1 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 350 53 73 89 94 97 99 100 100 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 G

44 19 15 9 7 11 10 3 4 0 7 3 0 0 0 0 0 0 0 0 0 0-0 0 0 132 33 48 59 66 71 80 87 89 92 92 98 100 0 0 0 0 0 0 0 0 0 0 0 0 0 TOTAL 1203 533 2?5188118 92 55 40 43 26 29 20 10 15 12 6 4 3 5 3 5 2 0 1 12 2770 (a)0f these 12 occurences of D stability which persisted over 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months s:

o two. lasted 25 hours2.893519e-4 days 0.00694 hours 4.133598e-5 weeks 9.5125e-6 months o two lasted 32 hours3.703704e-4 days 0.00889 hours 5.291005e-5 weeks 1.2176e-5 months o two lasted 26 hours3.009259e-4 days 0.00722 hours 4.298942e-5 weeks 9.893e-6 months o one lasted 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months o one lasted 27 hours3.125e-4 days 0.0075 hours 4.464286e-5 weeks 1.02735e-5 months o two lasted 44 hours5.092593e-4 days 0.0122 hours 7.275132e-5 weeks 1.6742e-5 months o one lasted 28 hours3.240741e-4 days 0.00778 hours 4.62963e-5 weeks 1.0654e-5 months o one lasted 46 hours5.324074e-4 days 0.0128 hours 7.60582e-5 weeks 1.7503e-5 months

TABLE 451.14-2 (Sheet 1 of 2)

STABILITY PERSISTENCE

SUMMARY

JUNE 1980-MAY 1981 a.43-150 Foot Delta-Temperature STABILITY FiRSISTENCE SUmARY - NURBER LT OBSERVAT]rftS AND PERCENT PROBABILITY STABILITY PEFIISTENCE Ut)URS)

, STABILITY I 23 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 GT.24 TOTAL A

99 49 36 23 26 16 19 14 6 5 52 0 0 0 0 0 0 0 0 0 0 0 0' O 300 33 49 61 69 78 83 89 94 96 98 99 100 0 0 0.0 0 0 0 0 0 0 0 0 0 B -311 105 32 16 5 1 3 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 474 66 88 95' 98 99 99 100 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 C

251 56 19 6 3 1 1 0 0 0 0 0 0 0 0 0 0 0 0- 0 0 0 0 0 0 337

-74 91 97 99 99 100 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 D

324 154 79 51 46 27 21 17 15 14 17 9 10 14 7 6 6 2 1 8 2 0 ~ 2 1 8 841 39 57 66 72 78 61 83 85 87 89 91 92 93 95 96 96 97 97 98 98 99 99 99 99 100 E

313 120 63.41.32 24 10 3 4 4 5 0 1 e 0 1 0 0 0 0 0 0 0 0 0 621

50. 70 80' 86 92 95 97 98 98 99 100 100 100 100 100 100 0 0 0 0 0 0 0 0 0 F

210 75 31 17 5 2 2 1 0 0 0 0 0 0 0 0 0 0 0 0 O O O O O 343 61 83 92 97 99 99 100 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

69 27 14 14 10 12 6 3 8 2 2 0 1 0 0 0 0 0 0 0 0 0 0 0 0

.168 41 57 65 74 80 87 90 92 97 98 99 99 100 0 0 0 0 0 0 0 0 0 0 0 0 TOTAll577 586 274 168 127 83 62 39 33 25 29 11 12 14 7 7 6 2 1 8 2 0 2 1 8 3084 (a)0f these 8 occurences of D stability which persisted over 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months s:

o one lasted 25 hours2.893519e-4 days 0.00694 hours 4.133598e-5 weeks 9.5125e-6 months o one lasted 35 hours4.050926e-4 days 0.00972 hours 5.787037e-5 weeks 1.33175e-5 months o one. lasted 27 hours3.125e-4 days 0.0075 hours 4.464286e-5 weeks 1.02735e-5 months o one lasted 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months o one lasted 28 hours3.240741e-4 days 0.00778 hours 4.62963e-5 weeks 1.0654e-5 months o one lasted 41 hours4.74537e-4 days 0.0114 hours 6.779101e-5 weeks 1.56005e-5 months o one lasted 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months o one lasted 50 hours5.787037e-4 days 0.0139 hours 8.267196e-5 weeks 1.9025e-5 months

i TABLE 451.14-2 l-(Sheet 2 of 2) b.43-209 Foot Delta-Temperature STABILITY FERSISTENCE SLNMARY - Nur$ER OF OBSERVATIONS AND PERCENT PROBABILITY STABILITY FIRSISTENCE OtJtRS)

STABILITY 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 GT.24 TOTAL

-A 70 33 14 9 11 5 5 7 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 156 45 66 75 81 88 91 94 99 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 9

195 67 26 11 2 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 302 65 87 95 99 100 100 0 0 0 0 0 0 0 0 0 0 0- 0 0 0 0 0 0 0 0 C

231 78 23 4 3 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 389

?2 92 98 99 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 D

259 140 101 57 35 22 21 23 21 12 12 10 12 6 8 10 4 6 4 4 1

1 3 1 15(*} 788 33 51 63 71 75 78 81 84 86 88 89 90 92 93 94 95 96 96 97 97 97 98 98 98 100 E

302 142 79 55 39 24 18 8 12 10 5 1 8 5 0 1 0 0 0 0 1 0 0 0 0 710 43 63 74 81 87 90 93 94 96 97 98 98 99 100 100 100 100 100 100 100 100 0 0 0 0 F

205 82 42 23 11 3 5 1 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 374 55 77 83 94 97 98 99 9? 99 100 100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

49 21 25 10 9' 11 5 2 10 5 1 1

1 0 0 0 0 0 0 0 0 0 0 0 0 150 33 47 63 70 76 83 87 88 95 98 99 99 100 0 0 0 0 0 0 0 0 0 0 0 0 TOTAL 1361 563 310 169 !!0 66 54 41 45 28 19 12 21 11 8 11 4 6 4 4 2 1 3 1 15 2869 (8)0f these 15 occurences of D stability which persisted over 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months s:

o three lasted 25 hours2.893519e-4 days 0.00694 hours 4.133598e-5 weeks 9.5125e-6 months o one lasted 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months o three lasted 27 hours3.125e-4 days 0.0075 hours 4.464286e-5 weeks 1.02735e-5 months o one lasted 42 hours4.861111e-4 days 0.0117 hours 6.944444e-5 weeks 1.5981e-5 months o one lasted 28 hours3.240741e-4 days 0.00778 hours 4.62963e-5 weeks 1.0654e-5 months o one lasted 45 hours5.208333e-4 days 0.0125 hours 7.440476e-5 weeks 1.71225e-5 months o one lasted 29 hours3.356481e-4 days 0.00806 hours 4.794974e-5 weeks 1.10345e-5 months o one lasted 46 hours5.324074e-4 days 0.0128 hours 7.60582e-5 weeks 1.7503e-5 months o one lasted 31 hours3.587963e-4 days 0.00861 hours 5.125661e-5 weeks 1.17955e-5 months o one lasted 50 hours5.787037e-4 days 0.0139 hours 8.267196e-5 weeks 1.9025e-5 months o one lasted 33 hours3.819444e-4 days 0.00917 hours 5.456349e-5 weeks 1.25565e-5 months

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ML20052H208

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