ML23151A486

PR-050 - 53FR41607 - Flow Control Conditions for the Standby Liquid Control System in Boiling Water Reactors

ML23151A486
Person / Time
Issue date:	10/24/1988
From:	Stello V NRC/EDO
To:
References
PR-050, 53FR41607
Download: ML23151A486 (1)

Text

{{#Wiki_filter:DOCUMENT DATE: TITLE: CASE

REFERENCE:

KEYWORD: ADAMS Template: SECY-067 10/24/1988 PR-050 - 53FR41607 - FLOW CONTROL CONDITIONS FOR THE STANDBY LIQUID CONTROL SYSTEM IN BOILING WATER REACTORS PR-050 53FR41607 RULEMAKING COMMENTS Document Sensitivity: Non-sensitive - SUNSI Review Complete

STATUS OF RULEMAKING PROPOSED RULE: PR-050 RULE NAME: FLOW CONTROL CONDITIONS FOR THE STANDBY LIQUID CON TROL SYSTEM IN BOILING WATER REACTORS PROPOSED RULE FED REG CITE: 53FR41607 PROPOSED RULE PUBLICATION DATE: 10/24/88 ORIGINAL DATE FOR COMMENTS: 12/23/88 NUMBER OF COMMENTS: EXTENSION DATE: I I 1 FINAL RULE FED. REG. CITE: 54FR13361 FINAL RULE PUBLICATION DATE: 04/03/89 NOTES ON EDO SIGNED PROPOSED AND FINAL RULES. TATUS OF RULE FILE LOCATED ON Pl. TO FIND THE STAFF CONTACT OR VIEW THE RULEMAKING HISTORY PRESS PAGE DOWN KEY HISTORY OF THE RULE PART AFFECTED: PR-050 RULE TITLE: PROPOSED RULE SECY PAPER: FINAL RULE SECY PAPER: FLOW CONTROL CONDITIONS FOR THE STANDBY LIQUID CON TROL SYSTEM IN BOILING WATER REACTORS PROPOSED RULE SRM DATE: FINAL RULE SRM DATE: I I I I DATE PROPOSED RULE SIGNED BY SECRETARY: 10/12/88 DATE FINAL RULE SIGNED BY SECRETARY: 03/21/89 STAFF CONTACTS ON THE RULE CONTACTl: WILLIAM R. PEARSON CONTACT2: MAIL STOP: NLS-129 PHONE: 492-3764 MAIL STOP: PHONE:

DOCKET NO. PR-050 (53FR41607) In the Matter of FLOW CONTROL CONDITIONS FOR THE STANDBY LIQUID CON TROL SYSTEM IN BOILING WATER REACTORS DATE DOCKETED DATE OF DOCUMENT TITLE OR DESCRIPTION OF DOCUMENT

10/12/88 12/27/88 04/26/89 10/12/88 12/20/88 03/21/89 FEDERAL REGISTER NOTICE - PROPOSED RULE COMMENT OF DETROIT EDISON (B. RALPH SYLVIA, VICE PRESIDENT) ( FEDERAL REGISTER NOTICE - FINAL RULE

1)

c- ~~~~6ltou~~cf PR W [53 (R 9 / b 07 J NUCLEAR REGULATORY COMMISSIO 10 CFR Part 50 RIN: 3150-AC72 (7590-01] Doer-APR 2 61989 ~& SECY~CH Flow Control Conditions for the Standby Liquid Control System in Boiling Water Reactors AGENCY: Nuclear Regulatory ColTlllission. ACTION: Final rule.

SUMMARY

The NRC is amending its regulations to set forth conditions and considerations for determining reactivity control capacity for boiling water reactQJ' standby liquid control systems. The changes are necessary to -c-"ifr.ify the existing regulation. EFFECTIVE DATE: (Insert a date 30 days following publication in the Federal Register.} FOR FURTHER INFORMATION CONTACT: ~illiam R. Pearson, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Cofflllission, Washington, DC 20555, telephone (301} 492-~764

• SUPPLEMENTARY INFORMATION:

On Monday, *October 24, published in the Federal Register (53 FR 41607) a proposed rule, nt!_tled "Flow Control Conditions for the Standby Liquid Control System in Boiling ,/" Water Reactors," that proposed amendments to 10 CFR 50.62. Interested parties were invited to submit written colTlllents within a 60-day co1J111ent period, which ended on December 23, 1988. One coll'lllent was received, which agreed with the proposed clarification. n b Ji, p.. '*" ~it_ r-u y~3-~~ o" )3 t l ~_s S~ f K) 1

I.I. S. .~r.'.l 'TQ, t*.-7v* O'. , r,.. PtH I.. '<J Cop1, P. Add'! Copi.

• ial Oi r'bu!:u:i

)vJJ I 3 f lJ tz. (] Of ftl{d Ill'-

rl No change to the proposed rule was suggested in the public COftlllent received by the NRC. The Connission believes that the proposed rule adequately clarifies reactivity control conditions for boiling water reactor standby liquid control systems (SLCS), thus, a final rule is being issued adopting the proposed rule without aodification. Environmental Impact: Categorical Exclusion The NRC has determined that this rule is the type of action described as a categorical exclusion in 10 CFR 51.22(c)(2). Thus, neither an environmental impact statement nor an envirorvnental assessment has been prepared. Paperwork Reduction Act Statement This rule does not contain a new or amended 1nforaation collection requirement subject to the Paperwork.Reduction Act of 1980 (44 U.S.C. 3501 et seq.). Existing re~uirements were approved by the Office of Management and Budget under control number 3150-0011. Regulatory Analysis Because this rule is of a clarifying nature and does not substan-tially change existing regulatory requirements, the.regulatory analysis prepared for the final rule entitled "Reduction of Risk froa Anticipated Transient$ Without Scram (ATWS) Events for Light-Water-Cooled Nuclear Power Plants," published June 26, 1984 (49 FR 26036) is still valid for 2

G for this rule. The analysis is available for inspection in the Public Document Room, 2120 L Street NW., Washington, DC, Lower Level. Single copies of the analysis aay be obtained from William R. Pearson, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 2~555, telephone (301)492-3764. Regulatory Flexibility Act Certification In accordance with the Regulatory Flexibility Act of 1980 (5 U.S.C. 605(b)), the Commission certifies that this rule will not have a signifi-cant economic impact on a substantial number of small entities and that therefore a regulatory flexibility analysis is not needed. This rule-making action affects only licensees that own and operate nuclear utili-zation facilities licensed under Sections 103 and 104 of the At011ic Energy Act of 1954, as amended. These licensees do not fall within the definition of small businesses set forth in Section 3 of the Small Business Act {15 U.S.C. 632) or within the Sllall Business Size Standards set forth in the regulations issued for the Small Business Administration at 13 CFR Part 121. Backfit Analysis The NRC has determined that the backfit rule, 10 CFR 50.109, does not apply to this rule, and therefore, that a backfit analysis is not required, because these amendments do not involve any provisions which impose backfits as defined in 10 CFR 50.109(a)(l). 3

C List of Subjects in 10 CFR Part 50 Antitrust, Classified infomation, Fire protection, Incorporation by reference, Intergovernmental relations, Nuclear power plants and reac-tors, Penalty, Radiation protection, Reactor siting criteria, Reporting and recordkeeping requirements. For the reasons set out in the preamble and under the authority of the Atomic Energy Act of 1954, as a11ended, the Energy Reorganization Act of 1974, as amended, and 5 U.S.C. 552 and 553, the NRC is adopting the following amendment to 10 CFR Part 50. PART 50 - DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION FACILITIES

1.

The authority citation for Part SO continues to read as follows: AUTHORITY: Secs. 102, 103, 104, 105, 161, 182, 183, 186, 189, 68 Stat. 936, 937, 938, 948, 953, 954, 955, 956, as amended, sec. 234, 83 Stat. 1244, as amended (42 U.S.C. 2132, 2133, 2134, 2135, 2201, 2232, 2233, 2236, 2239, 2282); secs. 201, as amended, 202, 206, ~ Stat. 1242, as amended, 1244, 1246 (42 U.S.C. 5841, 5842, 5846). Section 50.7 also issued under Pub. L. 95-601, sec. 10, 92 Stat *. 2951 {42 U.S.C. 5851). Section 50.10 also issued under secs. 101, 185, 68 Stat. 936, 955, as amended (42 U.S.C. 2131, 2235); sec. 102, Pub. L. 91-190, 83 Stat. 853 (42 U.S.C. 4332). Sections 50.13 and 50.54(dd) also issued under sec. 108, 68 Stat. 939, as amended (42 U.S.C. 2138). Sections 50.23, 50.35, 50.55, and 50.56 also issued under sec. 185, 68 Stat. 955 (42 U.S.C. 2235). Sections 50.33a, 50.SSa and Appendix Q also 4

issued under sec. 102, Pub. L. 91-190, 83 Stat. 853 (42 U.S.C. 4332). Sections 50.34 and 50.54 also issued under sec. 204, 88 Stat. 1245 (42 U.S.C. 5844). Sections 50.58, 50.91 and 50.92 also issued under Pub. L. 97-415, 96 Stat. 2073 (42 U.S.C. 2239). Section 50.78 also issued under sec. 122, 68 Stat. 939 (42 U.S.C. 2152). Sections 50.80-50-81 also issued under sec. 184, 68 Stat. 954, as amended (42 U.S.C. 2234). Section 50.103 also issued under sec. 108, 68 Stat. 939, as amended (42 U.S.C. 2138). Appendix F also issued under -se-c. 187, 68 Stat 955 (42 U.S.C. 2237). For the purposes of sec. 223, 68 Stat. 958, as amended (42 U.S.C. 2273), §§50.46(1) and (b), and 50.44(c) are issued under sec. 161b, 68 Stat. 948, as amended (42 U.S.C. 220l(b)); §§50.7(a), 50.10 (a)-(c), 50.34(1) and (e), 50.44(a)-(c), 50.46(1) and (b), 50.47(b), 50.48(1), (c), {d), and (e), 50.49(a), 50.54(a),(1), (1)(1), (1)-{n), (p), (q), (t), (v), and (y), 50.55(f), 50.551(1), {c)-(e), {g), and {h), 50.59(c), 50.60(1), 50.62(c), 50.64(b), and 50.80(a) and (b) are issued under sec. 1611, 68 Stat. 949, as amended (42 U.S.C. 2201 (1)); and §§50.49(d), (h), and (j), 50.54(w),(z),{bb),{cc), and (dd), 50.55(e), 50.59(b), 50.61(b), 50.62{b), 50.70(1), 50.71(a)-(c) and (e), 50.72(1), 50.73(a) and (b), 50.74, 50.78~ and 50.90 are issued under sec. 1610 1 68 Stat. 950, 1s amended (42 U.S.C. 2201(0)). I

2.

In§ 50.62, paragraph (c)(4) is revised to read as follows: § 50.62 Requirements for reduction of risk from anticipated transients without scram (ATWS) events for light-water-cooled nuclear power plants.

I (c) * * * (4) Each boiling water reactor must have a standby liquid control system (SLCS) with the capability of injecting into the reactor pressure vessel a borated water solution at such a flow rate, level of boron con-centration and boron-10 isotope enrichment, and accounting for reactor pressure vessel volume, that the resulting reactivity control is at least equivalent to that resulting from injection of 86 gallons per minute of 13 weight percent sodiUII pentaborate decahydrate solution at the natural boron-10 isotope abundance into a 251-inch inside diameter reactor pres-sure vessel for a given core design. The SLCS and its injection location must be designed to perform its function in a reliable manner. The SLCS initiation must be automatic and must be designed to perform its function in a reliable manner for plants granted a construction permit after July 26, 1984, and for plants granted a construction pennit prior to July 26, 1984, that have already been designed and built to include this feature. 6

Detroit Edison

e. Ralph Sylvia Senior Vice President 6400 North D1x1e Highway Newport. Michigan 48166 (313) 586-4150 oOCKET NUMBER

~ROPOSEO RU_L_E '. ~ ~ I: ' tl *** '88 OEC 27 P 3 :53 OF* !L. OOCKt. -,h"

. 1r f

~Kl ~errber 20, 1988 NJ:C-88-0300 The Secretary of the Corrnnission U.S. Nuclear Regulat ory Commission Washington. D. C. 20555 Attention: Docketing and Service Branch References :

1)

Fermi 2 NIC Docket No. 50-341 NIC License No. NPF-43

Subject:

Detroit :a:lison ' s Response to the Proposed Rul e Regarding Fl ow Control Conditions for the St arrlby Liquid Control System in Boiling Water Reoctors - 10 CFR Part 50 The Nuclear Regul at ory Corrnnission (NOC) has proposed to arrerrl its regulations concerning the fl ow condit ions for the St arrlby Liquid Control System (SLCS) in a Boiling Wat er Reoctor. The pr oposed rule would set for th cond itions and considerations for determining the recetivity cont rol capacity of a BWR Starrlby Liquid Control System. The Detroit :a:l ison Nuclear Engineer ing Depar tnent has ~eviewed the proposed rule changes for 10CFRS0.62, par agrcph (c) (4), on the "ra::luction of risk from anticipated t r ansients without scr am (A'IWS) events" arrl has no specific comrrentR. The pr oposed rule change was issued to clar i fy the existing r egulation. Detr oit :a:l ison is in agreement with the proposed cl ar ification. If you have any questions, please cont act Mr. Arnold J aufrnann at (313) 586-4213. cc: A. B. Davis R. C. Knop W. G. Rogers J. F. Stang Sincerely, 4£~5,b

• '*r (j)

,t1..,' _,.,<;;Ji!..V C-0 Ml5~, DOCKETING l. SERVICE SECHOR OfrlCE OF THE ~(CRH ARY Of THE C0.'-A/*t, l SS !ON Docum*;il Statistics Po~tmark Dato / J...../ ;J...:).)W CopiP.s P.ecei vr,J / Add' f Copi *s R,*;;*rodJcod ) _ 5J)t! ial Distribution ft[,{)~ ~ ~ _5_{)._..,_ _____ _

copy to Secy- ::=:::---, Original sent to tl'le Office of the redera\\ Reg\\a1Br for publication / rt 1. NUCLEAR REGULATORY COMMISSION 10 CFR Part 50 Flow Control Conditions for the Standby Liquid in Boiling Water Reactors AGENCY: Nuclear Regulatory Commission. ACTION: Proposed rule. [7590-01]

SUMMARY

The NRC is proposing to amend its regulations concerning the flow control conditions for the standby liquid control system in a boil-ing water reactor. The proposed rule would set forth conditions and considerations for determining the reactivity control capacity of a BWR standby liquid control system. The proposed changes are necessary to clarify the existing regulation. DATE: Comment period expires ( DEC 2 3 1988 ). Comments received after this date will be considered if it is practical to do so, but assurance of consideration cannot be given except as to those com-ments received on or before this date. ADDRESSES: Mail written comments to the Secretary: U.S. Nuclear Regulatory Commission, Washington, DC 20555; ATTN: Docketing and Service Branch. Deliver comments to 11555 Rockville Pike, Rockville, MD between 7:30 a.m. and 4:15 p.m. weekdays. Copies of comments received may be examined at the NRC Public Document Room (PDR) at 2120 L Street NW., Washington, DC, lower level. 1

[7590-01] FOR FURTHER INFORMATION CONTACT: William R. Pearson, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555, Telephone: (301)492-3764. SUPPLEMENTARY INFORMATION: On June 26, 1984, the Commission published in the Federal Register (49 FR 26036) a final rule entitled 11 Reduction of Risk from Anticipated Transients Without Scram (ATWS) Events for Light-Water-Cooled Nuclear Power Plants, 11 which revised the regulations in 10 CFR Part 50. The final rule required, at§ 50.62(c)(4), that boil-ing water reactors have a standby liquid control system (SLCS) with a minimum flow rate and boron content equivalent in [reactivity] control capacity to 86 gallons per minute (gpm) of 13 weight percent of sodium pentaborate solution. The rule did not specify the size of the reactor pressure vessel (RPV) into which this solution should be injected. Questions have been raised, especially from licensees with a smaller RPV, concerning the interpretation of the phrase, 11equivalent in control capacity. 11 On January 28~ 1985, a generic letter that provided clarifi-cation of this phrase was issued to appropriate licensees (PDR accession number 8501290633). This letter pr6vided the basis for the flow rate and weight percent of sodium pentaborate decahydrate and described how equiva-lency could be achieved* for a smaller RPV. The staff considers the con-tents of this letter, which were derived from the underlying materials considered when the rule was developed, to be technically correct. The letter is applicable to BWRs with (1) volume of water in the suppression pool per megawatt of core power ratios, (2) reactivity control systems, and (3) core designs similar to currently licensed BWR/1-6 designs. The language used in the existing rule is unclear and subject to differing 2

[7590-01] interpretations. The staff proposes to clarify the language to more precisely reflect the underlying technical bases. The standby liquid control system (SLCS) is designed to meet the requirements of general design criterion (GDC) number 26 of Appendix A to Part 50. GDC 26 states, 11Two independent reactivity control systems of different design principles shall be provided. One of the systems shall use control rods, preferably including a positive means for inserting the rods, and shall be capable of reliably controlling reactivity changes to assure that under conditions of normal operation, including anticipated operational occurrences, and with appropriate margins for malfunctions such as stuck rods, specified acceptable fuel design limits are not exceeded. The second reactivity control system shall be capable of reli-ably controlling the rate of reactivity changes resulting from planned, normal power changes (including xenon burnout) to assure acceptable fuel design limits are not exceeded. One of the systems shall be capable of holding the reactor core subcritical under cold conditions. 11 In the case of a boiling water reactor, the second reactivity control system is the SLCS. In addition, the SLCS is used to reduce risk from ATWS. The SLCS consists of a tank containing the sodium pentaborate decahydrate solution, two pumps, control instrumentation, appropriate piping, and means for testing the system without injecting the borate solution into the RPV. Sodium pentaborate decahydrate (NA2B100i6 *10H20) solution is prepared from a mixture of borax and boric acid dissolved in water. The solution nominally is a 13 weight percent solution of sodium pentaborate decahydrate in which the boron-10 isotope is at natural abundance (about 19.78%). A description o'f the SLCS and its functions is 3

[7590-01] given in the General Electric Co. document NED0-24222 (80 NEDD 21, Class I, ~ebruary 1981), entitled "Assessment of BWR Mitigation of ATWS, Volume I (NUREG-0406, Alternate No. 3), 11 sections 3.2, 6.1.3, and 7.2.10. The important parameters for reactivity control are the concentra-tion of the boron-10 isotope (which has a large thermal neutron capture cross-section) in the RPV cooling water and the time required to achieve this concentration. These parameters are in turn dependent upon the RPV volume (and therefore RPV inside diameter), boron injection flow rate, boron solution concentration, and boron-10 isotopic enrichment level. The standard that is specified in§ 50.62(c)(4), (86 gpm of 13 weight percent sodium pentaborate solution) assumes a boron-10 isotopic enrich-ment at the naturally occurring level and was intended to represent the reactivity control achieved for a BWR core design in a RPV with an inside diameter of 251 inches. Safety analyses show however, that equivalent reactivity contr.ol is achieved for a given core design in a different size RPV when the same boron-10 isotope concentration is provided within that RPV.

• Hence for a given core design, any combination of injection rate, boron solution concentration level, boron-10 isotopic enrichment level, and RPV volume that results in the same boron-10 concentration level within that RPV will provide reactivity control equivalent to the standard.

For example, 16.5 gpm of 26 weight percent sodium pentaborate solution enriched to twice the natural level of boron-10 content injected into a 218 inch inside diameter RPV provides reactivity control equivalent to the standard. 4

[7590-01] If sodium pentaborate decahydrate solution enriched in the boron-10 isotope is used, procedures should be established to assure proper dis-posal of the non-enriched solution and ensure that the boron-10 isotope concentration in the new solution is sufficient to shut down the reactor. Environmental Impact: Categorical Exclusion The NRC has determined that this proposed rule is the type of action described as a categorical exclusion in 10 CFR 51.22(c)(2). Thus, neither an environmental impact statement nor an environmental assessment has been prepared. Paperwork Reduction Act Statement This proposed rule does not contain a new or amended information collection requirement subject to the Paperwork Reduction' Act of 1980 (44 U.S.C. 3501 et seq.). Existing requirements were approved by the Office of Management and Budget under control number 3150-0011. Regulatory Analysis Since this proposed rule is of a clarifying nature and does not substantially change existing regulatory requirements, the regulatory analysis prepared for the final rule entitled 11Reduction of Risk from Anticipated Transients Without Scram (ATWS) Events for Light-Water-Cooled Nuclear Power Plants, 11 published June 26, 1984 (49 FR 26036) is still valid and will be used for this rule. The analysis is available for 5

[7590-01] inspection in the Public Document Room, 2120 L Street NW., Washington, DC, Lower Level. Single Copies of the analysis may be obtained from William R. Pearson, Office of Nuclear Regulatory Research, U.S. Nuclear Regulatory Commission, Washington, DC 20555, telephone (301)492-3764. Regulatory Flexibility Act Certification In accordance with the Regulatory Flexibility Act of 1980 (5 U.S.C. 605(b)), the Commission certifies that this rule, if promulgated, will not have a significant economic impact on a substantial number of small entities and that therefore a regulatory flexibility analysis need not be prepared. This rulemaking action would affect only licensees that own and operate nuclear utilization facilities licensed under Sections 103 and 104 of the Atomic Energy Act of 1954, as amended. These licensees do not fall within the definition of small businesses set forth in Section 3 of the Small Business Act (15 U.S.C. 632) or within the Small Business Size Standards set forth in the regulations issued for the Small Business Administration at 13 CFR Part 121. Backfit Analysis The NRC has determined that the backfit rule, 10 CFR 50.109, does not apply to this proposed rule, and therefore, that a backfit analysis is not required, because these amendments do not ~nvolve any provisions which would impose backfits as defined in 10 CFR 50.109(a)(l). 6

[7590-01] List of Subjects in 10 CFR Part 50 Antitrust, Classified information, Fire protection, Incorporation by reference, Intergovernmental relations, Nuclear power plants and reactors, Penalty, Radiation protection, Reactor siting criteria, Reporting and recordkeeping requirements. For the reasons set out in the preamble and under the authority of the Atomtc Energy Act of 1954, as amended, the Energy Reorganization Act of 1974, as amended, and 5 U.S.C. 552 and 553, the NRC is proposing to adopt the following amendment to 10 CFR Part 50. PART 50 - DOMESTIC LICENSING OF PRODUCTION AND UTILIZATION FACILITIES

1.

The authority citation for Part 50 continues to read as follows: AUTHORITY: Secs. 102, 103, 104, 105, 161, 182, 183, 186, 189, 68 Stat. 936, 937, 938, 948, 953, 954, 955, 956, as amended, sec. 234, 83 Stat. 1244, as amended (42 U.S.C. 2132, 2133, 2134, 2135, 2201, 2232, 2233, 2236, 2239, 2282); secs. 201, as amended, 202, 206, 88 Stat. 1242, as amended, 12~, 1246 (42 U.S.C. 5841, 5842, 5846). Section 50.7 also issued under Pub. L. 95-601, sec. 10, 92 Stat. 2951 (42 U.S.C. 5851). Section 50.10 also issued under secs. 101, 185, 68 Stat. 936, 955, as amended (42 U.S.C. 2131, 2235); sec. 102, Pub. L. 91-190, 83 Stat. 853 (42 U.S.C. 4332). Sections 50.23, 50.35, 50.55, and 50.56, also issued under sec. 185, 68 Stat. 955 (42 U.S.C. 2235). Sec-tions 50.33a, 50.55a, and Appendix Q also issued under sec. 102, Pub. L. 91-190, 83 Stat. 853 (42 U.S.C. 4332). Sections 50.34 and 50.54 also 7

[7590-01] issued under sec. 204, 88 Stat. 1245 (42 U.S.C. 5844). Sections 50.58, 50.91, and 50.92 also issued under Pub. L. 97-415, 96 Stat. 2073 (42 U.S.C. 2239). Section 50.78 also issued under sec. 122, 68 Stat. 939 (42 U.S.C. 2152). Sections 50.80-50.81 also issued under sec. 184, 68 Stat. ~54, as amended (42 U.S.C. 2234). Section 50.103 also issued under sec. 108, 68 Stat. 939, as amended (42 U.S.C. 2138). Appendix Falso issued under sec. 187, 68 _Stat. 955 (42 U.S.C. 2237). For the purposes of sec. 223, 68 Stat. 958 as amended (42 U.S.C. 2273); §§ 50.l0(a), (b), and (c), 50.44, 50.46, 50.48, 50.54 and 50.80(a) are issued under sec. 161b, 68 Stat. 948, as amended (42 U.S.C. 2201(b)); §§ 50.l0(b) and (c) and 50.54 are issued under sec. 16li, 68 Stat. 949, as amended (42 U.S.C. 2201(i)); and§§ 50.9, 50.55(e), 50.59(b), 50.70, 50.71, 50.72, 50.73, and 50.78 are issued under sec. 1610, 68 Stat. 950, as amended (42 U.S.C. 2201(0)).

2.

In§ 50.62, paragraph (c)(4) is revised to read as follows: § 50.62 Requirements for reduction of risk from anticipated transients without scram (ATWS) events for light-water-cooled nuclear power plants. (c) * * * (4) Each boiling water reactor must have a standby liquid control system (SLCS) with the capability of injecting into the reactor pressure vessel a borated water solution at such a flow rate, level of boron con-centration and boron-10 isotope enrichment, and accounting for reactor pressure vessel volume, that the resulting reactivity control is at least equivalent to that resulting from injection of 86 gallons per minute of 8

[7590-01] 13 weight percent sodium pentaborate decahydrate solution at the natural boron-10 isotope abundance into a 251 inch inside diameter reactor pres-sure vessel for a given core design. The SLCS and its injection location must be designed to perform its function in a reliable manner. The. SLCS initiation must be automatic and must be designed to perform its function in a reliable manner for plants granted a construction permit after July 26, 1984, and for plants granted a. construction permit prior to July 26, 1984, that have already been designed and built to include this feature. Dated at Rockville, Maryland, this~~day of CJ~ 1988. 9}}